tag:theconversation.com,2011:/fr/topics/ancient-dna-40563/articles
Ancient DNA – The Conversation
2024-03-14T19:24:37Z
tag:theconversation.com,2011:article/223970
2024-03-14T19:24:37Z
2024-03-14T19:24:37Z
From malaria, to smallpox, to polio – here’s how we know life in ancient Egypt was ravaged by disease
<figure><img src="https://images.theconversation.com/files/581183/original/file-20240312-29-m4tny7.jpg?ixlib=rb-1.1.0&rect=55%2C30%2C3338%2C2234&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>The mention of ancient Egypt usually conjures images of colossal pyramids and precious, golden tombs. </p>
<p>But as with most civilisations, the invisible world of infectious disease underpinned life and death along the Nile. In fact, fear of disease was so pervasive it influenced social and religious customs. It even featured in the statues, monuments and graves of the Kingdom of the Pharaohs. </p>
<p>By studying ancient specimens and artefacts, scientists are uncovering how disease rocked this ancient culture. </p>
<h2>Tutankhamun’s malaria, and other examples</h2>
<p>The most direct evidence of epidemics in ancient Egypt comes from skeletal and DNA evidence obtained from the mummies themselves.</p>
<p>For instance, DNA recovered from the mummy of the boy pharaoh Tutankhamun (1332–1323 BC) led to the discovery he <a href="https://pubmed.ncbi.nlm.nih.gov/20159872/">suffered from malaria</a>, along with several other New Kingdom mummies (circa 1800 BC). </p>
<p>In other examples:</p>
<ul>
<li>skeletal and DNA <a href="https://pubmed.ncbi.nlm.nih.gov/11289521/">evidence found</a> in the city of Abydos suggests one in four people may have had tuberculosis </li>
<li>the mummy of Ramesses V (circa 1149–1145 BC) has scars indicating smallpox </li>
<li>the wives of Mentuhotep II (circa 2000 BC) were buried hastily in a “mass grave”, suggesting <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9186437/">a pandemic</a> had occurred</li>
<li>and the mummies of two pharaohs, Siptah (1197–1191 BC) and Khnum-Nekht (circa 1800 BC), were <a href="https://link.springer.com/article/10.1007/s10072-016-2720-9">found with</a> the deformed <a href="https://www.shorelineortho.com/specialties/foot_ankle_equinus.php">equinus</a> foot which is characteristic of the viral disease polio.</li>
</ul>
<h2>Signs of a disease-ravaged people</h2>
<p>Amenhotep III was the ninth pharaoh of the 18th dynasty, and ruled from about 1388–1351 BC.</p>
<p>There are several reasons experts think his reign was marked by a devastating disease outbreak. For instance, two separate carvings from this time depict a priest and a royal couple with the polio dropped-foot. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/577699/original/file-20240224-30-9gt04r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/577699/original/file-20240224-30-9gt04r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/577699/original/file-20240224-30-9gt04r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=844&fit=crop&dpr=1 600w, https://images.theconversation.com/files/577699/original/file-20240224-30-9gt04r.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=844&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/577699/original/file-20240224-30-9gt04r.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=844&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/577699/original/file-20240224-30-9gt04r.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1060&fit=crop&dpr=1 754w, https://images.theconversation.com/files/577699/original/file-20240224-30-9gt04r.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1060&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/577699/original/file-20240224-30-9gt04r.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1060&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This 18th dynasty panel depicts a polio sufferer.</span>
<span class="attribution"><a class="source" href="https://en.m.wikipedia.org/wiki/File:Polio_Egyptian_Stele.jpg">Wikimedia</a></span>
</figcaption>
</figure>
<p>Statues of the lion-headed goddess of disease and health, Sekhmet, also <a href="https://pubmed.ncbi.nlm.nih.gov/33227516/">increased significantly</a>, suggesting a reliance on divine protection.</p>
<p>Another sign of a potential major disease outbreak comes in the form of what may be an early case of quarantine, wherein Amenhotep III moved his palace to the more isolated site of Malqata. This is further supported by the burning of a workers’ cemetery near Thebes. </p>
<p>Grave goods also became less extravagant and tombs less complex during this period, which suggests more burials were needed in a shorter time frame. These burials can’t be explained by war since this was an unusually peaceful period.</p>
<h2>Did disease trigger early monotheism?</h2>
<p>Amenohotep’s son – “the heretic King” Akhenaten (who was also Tutankhamun’s father) – abandoned the old gods of Egypt. In one of the earliest cases of monotheism, Akhenaten made worship of the Sun the official state religion. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/577700/original/file-20240224-26-gurcmn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/577700/original/file-20240224-26-gurcmn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=755&fit=crop&dpr=1 600w, https://images.theconversation.com/files/577700/original/file-20240224-26-gurcmn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=755&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/577700/original/file-20240224-26-gurcmn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=755&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/577700/original/file-20240224-26-gurcmn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=949&fit=crop&dpr=1 754w, https://images.theconversation.com/files/577700/original/file-20240224-26-gurcmn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=949&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/577700/original/file-20240224-26-gurcmn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=949&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">This panel (circa 1372-1355 BC) shows Akhenaten, Nefertiti and their daughters adoring the Sun god Aten.</span>
<span class="attribution"><a class="source" href="https://en.m.wikipedia.org/wiki/File:La_salle_dAkhenaton_(1356-1340_av_J.C.)_(Mus%C3%A9e_du_Caire)_(2076972086).jpg">Wikimedia</a></span>
</figcaption>
</figure>
<p>Some <a href="https://www.thecollector.com/akhenaten-monotheism-plague-egypt/">researchers think</a> Akhenaten’s dramatic loss of faith may have been due to the devastating disease he witnessed during his childhood and into his reign, with several of his children and wives having died from disease. But we’ve yet to find clear evidence for the role of disease in shaping his theology.</p>
<p>There’s also no direct DNA evidence of an outbreak under his father, Amenhotep III. There are only descriptions of one <a href="https://www.nationalgeographic.co.uk/history-and-civilisation/2021/01/these-pharaohs-private-letters-expose-how-politics-worked-3300-years-ago">in letters</a> Amenhotep III and Akhenaten exchanged with the Babylonians. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/580627/original/file-20240308-16-mt400i.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/580627/original/file-20240308-16-mt400i.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/580627/original/file-20240308-16-mt400i.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=302&fit=crop&dpr=1 600w, https://images.theconversation.com/files/580627/original/file-20240308-16-mt400i.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=302&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/580627/original/file-20240308-16-mt400i.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=302&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/580627/original/file-20240308-16-mt400i.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=380&fit=crop&dpr=1 754w, https://images.theconversation.com/files/580627/original/file-20240308-16-mt400i.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=380&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/580627/original/file-20240308-16-mt400i.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=380&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">These clay tablets (circa 14th century BC), inscribed in Babylonian cuneiform, were sent to Amenhotep III or Akhenaten from the ruler Abdi-tirshi of Hazor (modern-day Israel).</span>
<span class="attribution"><span class="source">British Museum</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<p>To confirm an outbreak under Amenhotep III, we’d need to first recover pathogen DNA in human remains from this time, has been found in other Egyptian burial sites and for <a href="https://pubmed.ncbi.nlm.nih.gov/21993626/">other pandemics</a>.</p>
<p>Also, while many ancient epidemics are referred to as “plagues”, we can’t confirm whether any outbreaks in ancient Egypt were indeed caused by <em>Yersinia pestis</em>, the bacteria responsible for bubonic plague pandemics <a href="https://www.britannica.com/event/Black-Death">such as the Black Death</a> in Europe (1347-1351). </p>
<p>That said, researchers <a href="https://www.jstor.org/stable/3554655">have confirmed</a> the Nile rat, which was widespread during the time of the Pharaohs, would have been able to carry the <em>Yersinia</em> infection.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/579796/original/file-20240305-24-p439xf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/579796/original/file-20240305-24-p439xf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/579796/original/file-20240305-24-p439xf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=427&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579796/original/file-20240305-24-p439xf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=427&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579796/original/file-20240305-24-p439xf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=427&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579796/original/file-20240305-24-p439xf.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=537&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579796/original/file-20240305-24-p439xf.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=537&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579796/original/file-20240305-24-p439xf.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=537&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">This 1811 etching depicts the ancient Plague of Athens (circa 430 BC), which may have been caused by <em>Yersinia</em> or a disease with similar symptoms such as smallpox, typhus or measles.</span>
<span class="attribution"><a class="source" href="https://www.britishmuseum.org/collection/image/1047063001">The British Museum</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>How were outbreaks managed?</h2>
<p>Much like modern pandemics, factors such as population growth, sanitation, population density and mobilisation for war would have influenced the spread of disease in ancient Egypt. </p>
<p>In the case of war, it’s thought the Hittite army was <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9186437/">weakened by</a> disease spread when it was famously <a href="https://www.khanacademy.org/humanities/world-history/world-history-beginnings/ancient-egypt-hittites/a/the-hittites">defeated by</a> Egyptian Pharaoh Ramses the Great in the battle of Kadesh (1274 BC). </p>
<p>In some ways, Egyptian medicine was advanced for its time. While these outbreaks occurred long before the development of antibiotics or vaccines, there is some evidence of public health measures such as the burning of towns and quarantining people. This suggests a basic understanding of how disease spreads. </p>
<p>Diseases caused by microorganisms would have been viewed as supernatural, or as a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1121911/">corruption of the air</a>. This is similar to other explanations held in different parts of the world, before germ theory was popularised in the 19th century.</p>
<h2>New world, old problems</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/579797/original/file-20240305-28-cqzgoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/579797/original/file-20240305-28-cqzgoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/579797/original/file-20240305-28-cqzgoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=750&fit=crop&dpr=1 600w, https://images.theconversation.com/files/579797/original/file-20240305-28-cqzgoc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=750&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/579797/original/file-20240305-28-cqzgoc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=750&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/579797/original/file-20240305-28-cqzgoc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=943&fit=crop&dpr=1 754w, https://images.theconversation.com/files/579797/original/file-20240305-28-cqzgoc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=943&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/579797/original/file-20240305-28-cqzgoc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=943&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The funerary mask of Tutankhamun, who died as a teenager.</span>
<span class="attribution"><a class="source" href="https://en.m.wikipedia.org/wiki/File:CairoEgMuseumTaaMaskMostlyPhotographed.jpg">Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Many of the most widespread diseases that afflicted the ancient world are still with us.</p>
<p>Along with Tutankhamun, it’s thought <a href="https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(17)30261-X/abstract">up to 70%</a> of the Egyptian population was infected with malaria caused by the <em>Plasmodium falciparum</em> parasite – spread by swarms of mosquitoes occupying the stagnant pools of the Nile delta. </p>
<p>Today, malaria affects about 250 million people, mostly in developing nations. Tuberculosis kills more than a million people each year. And smallpox and polio have only recently been eradicated or controlled through vaccination programs.</p>
<p>More work is yet to be done to detect individual pathogens in Egyptian mummies. This knowledge could shed light on how, throughout history, people much like us have grappled with these unseen organisms.</p>
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<p>
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<strong>
Read more:
<a href="https://theconversation.com/did-everyone-in-bridgerton-have-syphilis-just-how-sexy-would-it-really-have-been-in-regency-era-london-180581">Did everyone in Bridgerton have syphilis? Just how sexy would it really have been in Regency era London?</a>
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</p>
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<img src="https://counter.theconversation.com/content/223970/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Jeffries does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Beyond the tombs and riches, life in ancient Egypt wasn’t so luxurious, after all.
Thomas Jeffries, Senior Lecturer in Microbiology, Western Sydney University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/216998
2024-02-20T19:57:06Z
2024-02-20T19:57:06Z
Ancient DNA reveals children with Down syndrome in past societies. What can their burials tell us about their lives?
<figure><img src="https://images.theconversation.com/files/575544/original/file-20240214-26-4oegvh.jpeg?ixlib=rb-1.1.0&rect=0%2C4%2C3264%2C1827&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Las_Eretas_aztarnategiko_etxearen_oinarriak.jpg">Suna no onna / Wikimedia</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>After analysing DNA from almost 10,000 people from ancient and pre-modern societies, our international team of researchers have discovered six cases of Down syndrome in past human populations.</p>
<p>Our results, published today in <a href="https://www.nature.com/articles/s41467-024-45438-1">Nature Communications</a>, show people with Down syndrome lived in ancient populations. Although these individuals were very young when they died, they were all buried with care, indicating they were appreciated as members of their communities.</p>
<h2>Down syndrome in humans</h2>
<p>The DNA in our cells (our genome) is separated into 23 chromosomes, much like a book is separated into chapters. Most people carry two “versions” of the first 22 chromosomes, one from each of their parents. In some cases, people can have a third, extra copy of chromosome 21 (this condition is called trisomy 21). </p>
<p>This extra copy of chromosome 21 changes how the body and brain develop. People with trisomy 21 will have some level of intellectual disability and some characteristic physical features (such as almond-shaped eyes or a shorter height). The physical features that can result from trisomy 21 are called <a href="https://www.downsyndrome.org.au/about-down-syndrome/what-is-down-syndrome/">Down syndrome</a>.</p>
<p>However, not every person with Down syndrome has the same physical features, and many of these features are not visible in the skeleton. This has made diagnosing Down syndrome from archaeological remains, which are often damaged and incomplete skeletons, very difficult. </p>
<p>However, we <em>can</em> detect trisomy 21 from even very small amounts of ancient DNA. This is because an additional chromosome 21 will lead to noticeably more DNA from chromosome 21 being present among the DNA that can be extracted from old bones and teeth.</p>
<h2>Discovered across different times and places</h2>
<p>After screening nearly 10,000 DNA samples, we identified six individuals with Down syndrome. </p>
<p>In our research, we screened nearly 10,000 DNA samples from across the world, dating as far back as when humans were hunter-gatherers. The six individuals we identified with Down syndrome were all from Europe, likely because this is where most of our ancient DNA samples were from. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/in-a-stone-age-cemetery-dna-reveals-a-treasured-founding-father-and-a-legacy-of-prosperity-for-his-sons-206940">In a Stone Age cemetery, DNA reveals a treasured 'founding father' and a legacy of prosperity for his sons</a>
</strong>
</em>
</p>
<hr>
<p>One individual was buried in the 17th or 18th century in a church graveyard in Helsinki, Finland, under what is now a popular tourist attraction, the <a href="https://www.myhelsinki.fi/en/see-and-do/sights/senate-square">Helsinki Senate Square</a>. </p>
<p>Another individual was discovered on the Greek island of <a href="https://www.aeginagreece.com/aegina/pages/history/index.html">Aegina</a>, the closest Mediterranean island to Athens. This individual lived approximately 3,300 years ago, and was buried next to a house, with a rare and intricate bead necklace. </p>
<p>A third individual was discovered at the Bronze Age Bulgarian tell site (a settlement on a man-made hill) of <a href="https://doi.org/10.1038/s41586-023-06334-8">Yunatsite</a>, dating to around 4,800 years ago. This infant was buried under the floor of the home in a so-called “urn burial”.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/559452/original/file-20231114-15-iv5hk5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of the remains of a small human skeleton." src="https://images.theconversation.com/files/559452/original/file-20231114-15-iv5hk5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/559452/original/file-20231114-15-iv5hk5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=411&fit=crop&dpr=1 600w, https://images.theconversation.com/files/559452/original/file-20231114-15-iv5hk5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=411&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/559452/original/file-20231114-15-iv5hk5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=411&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/559452/original/file-20231114-15-iv5hk5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=517&fit=crop&dpr=1 754w, https://images.theconversation.com/files/559452/original/file-20231114-15-iv5hk5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=517&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/559452/original/file-20231114-15-iv5hk5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=517&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The inhumation of the perinatal infant with Down syndrome from the Iron Age site of Las Eretas. This individual was buried within one of the houses in the settlement.</span>
<span class="attribution"><span class="source">Photographs from the Government of Navarre and J.L. Larrion.</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>The remaining three individuals were found in two Iron Age sites in Spain, <a href="https://doi.org/10.11588/propylaeum.1280">Alto de la Cruz and Las Eretas</a>, dating to approximately 2,500 years ago. According to the estimates of their age at death, these babies likely did not survive to birth. </p>
<p>However, they were buried with care within homes or within special buildings reserved for rituals. These burials were remarkable, as most people of the region during these times were cremated instead of buried.</p>
<p>We also compared the skeletons of the individuals with Down syndrome to identify common skeletal differences, such as irregular bone growth, or porosity of the skull bones. </p>
<p>“Learning from this work may help to identify future cases of Down syndrome from skeletons when ancient DNA can’t be recovered,” says our co-author Patxuka de-Miguel-Ibáñez of the University of Alicante, the lead osteologist for the Spanish sites in the study.</p>
<h2>An unexpected discovery</h2>
<p>At one of the same Iron Age Spanish sites, we also identified an infant that carried an extra copy of chromosome 18. This condition, called <a href="https://raisingchildren.net.au/guides/a-z-health-reference/trisomy-18">Edwards syndrome</a>, causes much more severe physical differences, which could be observed in the skeletal remains. This baby likely only survived to 40 weeks’ gestation, but was also given a special burial.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/563237/original/file-20231204-22-9dw6do.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="An illustration of a settlement." src="https://images.theconversation.com/files/563237/original/file-20231204-22-9dw6do.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/563237/original/file-20231204-22-9dw6do.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/563237/original/file-20231204-22-9dw6do.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/563237/original/file-20231204-22-9dw6do.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/563237/original/file-20231204-22-9dw6do.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=538&fit=crop&dpr=1 754w, https://images.theconversation.com/files/563237/original/file-20231204-22-9dw6do.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=538&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/563237/original/file-20231204-22-9dw6do.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=538&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A reconstruction of the Early Iron Age settlement of Las Eretas, Navarra.</span>
<span class="attribution"><span class="source">Iñaki Diéguez / Javier Armendáriz, Museo Las Eretas, Navarra</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<p>The fact that three cases of Down syndrome and the one case of Edwards syndrome were found in just two contemporaneous and nearby settlements was a surprise to us. </p>
<p>“We don’t know why this happened,” says our co-author Roberto Risch, an archaeologist from The Autonomous University of Barcelona. “But it appears as if these people were purposefully choosing these infants for special burials.”</p>
<h2>A view of our past</h2>
<p>Today, individuals with Down syndrome live full and happy lives as valued members of our communities. Notably, our research found no adult individuals with Down syndrome. However, this study shows the perinates and infants that were found were clearly buried with care. In the case where a newborn survived, they were cared for until death. </p>
<p>As we discover and analyse more of these sorts of cases, we will be able to investigate the questions of how our near and distant ancestors viewed rare and uncommon genetic syndromes and how they cared for one another in these cases.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-thought-the-first-hunter-gatherers-in-europe-went-missing-during-the-last-ice-age-now-ancient-dna-analysis-says-otherwise-200899">We thought the first hunter-gatherers in Europe went missing during the last ice age. Now, ancient DNA analysis says otherwise</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/216998/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
After sifting through DNA from almost 10,000 people from ancient and pre-modern societies, we have discovered six cases of Down syndrome in past human populations.
Adam "Ben" Rohrlach, Mathematics Lecturer and Ancient DNA Researcher, University of Adelaide
Kay Prüfer, Group leader, Department of Archaeogenetics, Max Planck Institute for Evolutionary Anthropology
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/219620
2024-01-18T16:38:26Z
2024-01-18T16:38:26Z
DNA from stone age chewing gum sheds light on diet and disease in Scandinavia’s ancient hunter-gatherers
<figure><img src="https://images.theconversation.com/files/570142/original/file-20240118-27-aehxwa.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C464%2C352&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A mold cast of one of the chewed pitch pieces.</span> <span class="attribution"><span class="source">Verner Alexandersen</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Some 9,700 years ago on an autumn day, a group of people were camping on the west coast of Scandinavia. They were hunter-gatherers that had been fishing, hunting and collecting resources in the area. </p>
<p>Some teenagers, both boys and girls, were chewing resin to produce glue, just after eating trout, deer and hazelnuts. Due to a severe gum infection (periodontitis), one of the teenagers had problems eating the chewy deer-meat, as well as preparing the resin by chewing it.</p>
<p>This snapshot of the Mesolithic period, just before Europeans started farming, comes from analysis of DNA left in the chewed resin that we have conducted, now <a href="https://www.nature.com/articles/s41598-023-48762-6">published in Scientific Reports</a>. </p>
<p>The location is now known as <a href="https://lup.lub.lu.se/search/publication/3c1fd58a-9495-4403-ab7d-d22104f2fafb">Huseby Klev</a>, situated north of Gothenburg (Göteborg), Sweden. <a href="https://www.cambridge.org/core/journals/antiquity/article/abs/wet-and-the-wild-followed-by-the-dry-and-the-tame-or-did-they-occur-at-the-same-time-diet-in-mesolithic-neolithic-southern-sweden/D91F7830FE704FD24DFAFB55E551039B">It was excavated</a> by archaeologists in the early 1990s, and yielded some 1,849 flint artefacts and 115 pieces of resin (mastic). The site has been radiocarbon dated to between 10,200 and 9,400 years ago, with one of the pieces of resin dated to 9,700 years ago.</p>
<p>Some of the resin has teeth imprints, indicating that children, actually teenagers, had been chewing them. Masticated lumps, often with imprints of teeth, fingerprints or both, are not uncommon to find in Mesolithic sites. </p>
<p>The pieces of resin we have analysed were made of <a href="https://www.nature.com/articles/s41467-019-13549-9">birch bark pitch</a>, which is known to have been used as an <a href="https://phys.org/news/2019-08-neanderthal-tool-making-simpler-previously-thought.html">adhesive substance in stone tool technology</a> from the Middle Palaeolithic onward. However, they were also chewed for recreational or medicinal purposes in traditional societies.</p>
<p>A variety of substances with similar properties, such as resins from coniferous trees, natural bitumen, and other plant gums, are known to have been used in analogous ways in many parts of the world.</p>
<h2>The power of DNA</h2>
<p>In some of the resin, half the <a href="https://www.nature.com/articles/s42003-019-0399-1">DNA extracted</a> was of human origin. This is a lot compared to what we often find in ancient bones and teeth. </p>
<p>It represents some of the oldest human genomes from Scandinavia. It has a particular ancestry profile common among Mesolithic hunter gatherers who once lived there. </p>
<p>Some of the resin contains male human DNA while others have female DNA. We think that teenagers of both sexes were preparing glue for use in tool making, such as attaching a stone axe to a wooden handle.</p>
<p>But what of the other half of the DNA that was of non-human origin? Most of this DNA is from organisms such as bacteria and fungi that have lived in the mastic since it was discarded 9,700 years ago. But some of it was from bacteria living in the human that chewed it, along with material the human had been chewing on before they put the birch bark pitch in their mouths.</p>
<p>Analysing all this DNA is a demanding task and treads new ground. We had to both adapt existing computing tools and also develop some new analytical strategies. As such, this work has become the starting point for developing a new workflow for this kind of analysis. </p>
<p>This includes mining the DNA using different strategies to characterise it, trying to piece together short DNA fragments into longer ones and using machine learning techniques to work out which DNA fragments belong to pathogens (harmful microorganisms). It also involves comparing the data to what we see in the mouths of modern people with <a href="https://www.ncbi.nlm.nih.gov/books/NBK551699/">tooth decay (caries)</a> and periodontitis.</p>
<h2>Higher organisms</h2>
<p>Naturally, we found the kind of bacteria that would be expected in an oral microbiome, the range of naturally occurring microorganisms found in the mouth. We also found traces of bacteria implicated in conditions such as tooth decay or caries (<em>Streptococcus mutans</em>), and systemic diseases such as Hib disease and endocarditis. There were also bacteria that can cause abscesses. </p>
<p>Although these pathogenic microorganisms were present at an elevated frequency, they were not clearly above the level expected for a healthy oral microbiome. There is thus no conclusive evidence that members of the group suffered from diseases these microorganisms are associated with. </p>
<p>What we did find, however, was an abundance of bacteria associated with serious gum disease – <a href="https://www.mayoclinic.org/diseases-conditions/periodontitis/symptoms-causes/syc-20354473">periodontitis</a>. When we applied a <a href="https://www.ibm.com/topics/machine-learning">machine learning</a> strategy (in this case, a technique called <a href="https://www.ibm.com/topics/random-forest">Random Forest modelling</a>) we reached the conclusion that the girl who chewed one of the pieces of resin had probably suffered from periodontitis – with more than a 75% probability.</p>
<p>We also found DNA from larger organisms than just bacteria. We found DNA for red deer, brown trout and hazelnuts. This DNA probably came from material the teenagers had been chewing before they put the birch pitch in their mouths. </p>
<p>However, we need to be a little bit cautious because exactly what we find is also dependent on the comparison data that we have. As genomes from eukaryotic organisms – the group that includes plants and animals – <a href="https://www.ncbi.nlm.nih.gov/books/NBK9846/">are larger and more complex</a> than those from microorganisms, it is more complicated to assemble a eukaryotic genome of high quality. </p>
<p>There are fewer eukaryotic genomes in the samples of resin, and they are of lower quality. This means that our brown trout, for example, may not actually be a brown trout, but we at least feel certain it is from the salmon family.</p>
<p>We also found a lot of fox DNA, but this is harder to interpret. Fox meat may have been a part of the diet, but these teenagers could also have chewed on tendons and fur from foxes for use in textiles. Alternatively, the fox DNA could even be from territorial marking and got into the resin after it was spat out.</p>
<p>However, what we have learned for sure represents a big step in understanding these fascinating records of human culture from the Stone Age. As we analyse more of these, even more surprises could emerge.</p><img src="https://counter.theconversation.com/content/219620/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anders Götherström receives funding from: the Swedish Research Council (2019-00849_VR), Riksbankens Jubileumsfond (P16-0553:1)</span></em></p><p class="fine-print"><em><span>Emrah Kırdök does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Genetic analysis reveals one of the teenagers probably had advanced gum disease.
Anders Götherström, Professor in Molecular Archaeology, Department of Archaeology and Classical Studies, Stockholm University
Emrah Kırdök, Assistant Professor, Department of Biotechnology, Mersin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/217868
2023-12-14T19:00:58Z
2023-12-14T19:00:58Z
Mutton, an Indigenous woolly dog, died in 1859 − new analysis confirms precolonial lineage of this extinct breed, once kept for their wool
<figure><img src="https://images.theconversation.com/files/562497/original/file-20231129-22-cxtdyy.jpg?ixlib=rb-1.1.0&rect=0%2C444%2C2995%2C2883&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Indigenous Coast Salish women wove woolly dogs' fur into blankets.</span> <span class="attribution"><span class="source">Artist's reconstruction by Karen Carr</span></span></figcaption></figure><p>Dogs have been in the Americas for more than 10,000 years. They were already domesticated when they <a href="https://doi.org/10.1126/science.aao4776">came from Eurasia with the first people</a> to reach North America. In the coastal parts of present-day Washington state and southwestern British Columbia, archaeologists have found dog remains dating back as far as <a href="https://doi.org/10.1016/j.jaa.2020.101209">about 5,000 years ago</a>.</p>
<p>Dogs performed many different roles in North American Indigenous communities, including transportation, that in other parts of the world were done by multiple other domestic animals. </p>
<p>Prior to the arrival of Europeans, the <a href="https://www.burkemuseum.org/collections-and-research/culture/contemporary-culture/coast-salish-art/coast-salish-people">Indigenous Coast Salish peoples</a> of the Pacific Northwest had traditionally maintained a breed of long-haired dog for the purpose of harvesting their hair, or wool, for textile fibers. Along with <a href="https://doi.org/10.1016/0305-4403(95)90012-8">alpacas and llamas</a>, these woolly dogs are one of only a few known animals intentionally bred for their fleece in all of the Americas.</p>
<p>But the practice of keeping woolly dogs and weaving textiles made from woolly dog yarn declined throughout the 19th century, and the dogs were considered extinct by the beginning of the 20th century. What had happened to them? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/562505/original/file-20231129-19-wyniuw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="dog paw on furry pelt with handwritten tag" src="https://images.theconversation.com/files/562505/original/file-20231129-19-wyniuw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562505/original/file-20231129-19-wyniuw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562505/original/file-20231129-19-wyniuw.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562505/original/file-20231129-19-wyniuw.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562505/original/file-20231129-19-wyniuw.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562505/original/file-20231129-19-wyniuw.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562505/original/file-20231129-19-wyniuw.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Mutton’s pelt has been preserved at the Smithsonian Institution for more than 160 years.</span>
<span class="attribution"><span class="source">Audrey Lin</span></span>
</figcaption>
</figure>
<p>Today, the only confirmed woolly dog specimen is “Mutton,” whose pelt has been housed <a href="http://n2t.net/ark:/65665/3299968b9-99b2-4db0-9aee-b8ee388fcb57">in the Smithsonian’s collection</a> since his death in 1859. In life, this “Indian dog” was the companion of <a href="https://en.wikipedia.org/wiki/George_Gibbs_(ethnologist)">George Gibbs</a>, a naturalist working on the Northwest Boundary Survey expedition to map out British Columbia and the American Pacific Northwest. In death, Mutton offered the opportunity to learn more about woolly dog ancestry, selection and management.</p>
<p>We are <a href="https://scholar.google.com/citations?user=th7mXK0AAAAJ&hl=en&oi=ao">an archaeologist</a>, an <a href="https://scholar.google.com/citations?user=5sYVrEsAAAAJ&hl=en&oi=ao">evolutionary molecular biologist</a> and a <a href="https://scholar.google.com/citations?user=G5OGkjUAAAAJ&hl=en&oi=ao">molecular anthropologist</a> who are part of a large research team. It’s important to note that although we collaborated with a number of Indigenous people on our study, the scientists, including the three of us, are not Indigenous. Alongside historical documents and interviews of Coast Salish elders, knowledge keepers, weavers and artists, our team utilized “<a href="https://doi.org/10.1111/faf.12516">Two-Eyed Seeing</a>” – viewing the world through the combined strengths of Indigenous knowledge and western science – to <a href="https://doi.org/10.1126/science.adi6549">bring Mutton’s story and legacy back to life</a>.</p>
<h2>A prestigious part of Indigenous culture</h2>
<p>Prior to the arrival of Europeans, there were <a href="https://archpress.lib.sfu.ca/index.php/archpress/catalog/download/52/23/1900?inline=1">several types of dogs</a> in the Pacific Northwest: larger “village” dogs and hunting dogs and smaller <a href="https://hakaimagazine.com/features/the-dogs-that-grew-wool-and-the-people-who-love-them/">woolly dogs</a>, kept separately to prevent interbreeding. Woolly dogs were a little larger than the modern <a href="https://www.akc.org/dog-breeds/american-eskimo-dog/">American Eskimo dog breed</a> and had curled tails, pricked ears and a pointed foxlike face. Instead of barking, they howled. </p>
<p>Traditionally, only high-status Coast Salish women were allowed to keep woolly dogs, and a woman’s individual wealth could be measured by how many she had. Blankets woven of dog hair, often mixed with hair from mountain goats and waterfowl or plant fibers, were important trade and gift items.</p>
<p>Historians and economists, looking back, first claimed the disappearance of the woolly dog breed was the result of simple capitalist forces: The availability of cheap manufactured blankets offered by businesses like the <a href="https://www.hbcheritage.ca/things/fashion-pop/hbc-point-blanket">Hudson’s Bay Company</a> meant the Coast Salish didn’t need to make their own blankets. Why go through the immense time and labor in keeping wool dogs and crafting blankets in the traditional way when you could just buy a machine-woven blanket? </p>
<p>But the Coast Salish don’t agree. <a href="https://vanmuralfest.ca/blog/debra-sparrow">Debra qwasen Sparrow</a>, a master weaver of the <a href="https://www.musqueam.bc.ca/">Musqueam Nation</a>, explained to us, “The blankets really tell a story of our history, our families, the way in which they identified in the communities, (they’re) all reflected in the blankets.”</p>
<p>And Coast Salish people say they would never have willingly parted with their beloved canine friends. The simple economic explanation ignores the massive role colonialism played in the demise of the woolly dogs. Repressive government policies <a href="https://www.washington.edu/uwired/outreach/cspn/Website/Classroom%20Materials/Pacific%20Northwest%20History/Lessons/Lesson%2012/12.html">tried to control and subdue</a> <a href="https://www.kitsapsun.com/story/news/2022/05/12/indian-boarding-schools-operated-washington-state-interior-department-deb-haaland/9749676002/">Indigenous cultural practices</a>.</p>
<p>“They were told they couldn’t do their cultural things. There was the police, the Indian agent and the priests,” <a href="https://www.stolonation.bc.ca">Stó:lō Nation</a> elder Xweliqwiya Rena Point Bolton told our research team. “The dogs were not allowed. (My grandmother) had to get rid of the dogs. And so the family never ever saw them.”</p>
<p>Eventually, there were no more Coast Salish woolly dogs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/565318/original/file-20231212-23-cut1vu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="pelt fur-side down on a paper-covered table" src="https://images.theconversation.com/files/565318/original/file-20231212-23-cut1vu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/565318/original/file-20231212-23-cut1vu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=468&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565318/original/file-20231212-23-cut1vu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=468&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565318/original/file-20231212-23-cut1vu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=468&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565318/original/file-20231212-23-cut1vu.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=588&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565318/original/file-20231212-23-cut1vu.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=588&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565318/original/file-20231212-23-cut1vu.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=588&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Researchers used a portable X-ray fluorescence analyzer as part of their investigation of Mutton’s remains.</span>
<span class="attribution"><span class="source">Audrey Lin</span></span>
</figcaption>
</figure>
<h2>Piecing together a picture of Mutton’s life</h2>
<p>We did have access to Mutton’s pelt, though, which had been archived for more than 160 years. No one knows exactly how Gibbs initially acquired Mutton, but it’s likely he got the dog while working with local communities in <a href="https://www.stolonation.bc.ca/">Stó:lō territory</a> in present-day British Columbia. Using modern techniques, we set out to answer questions about Mutton’s breed and ancestry.</p>
<p>First we used <a href="https://www.nature.com/scitable/knowledge/library/the-use-of-stable-isotopes-in-the-96648168/">stable isotope analysis</a>, a chemical analysis of once-living tissues, to understand more about Mutton’s environment when he was alive: what kinds of foods he ate and the state of his health.</p>
<p>Interviews of the <a href="https://doi.org/10.1126/science.adi6549">elders and knowledge keepers confirmed</a> that the woolly dog diet was very different from village dogs, including special foods that kept the dogs healthy and their coats shiny. For example, salmon, elk or certain local plants would be set aside for the woolly dogs. </p>
<p>The stable isotope values of Mutton’s fur suggested he’d been eating maize for some time, but less and less up to the point when he died. The <a href="https://www.trafford.com/en/bookstore/bookdetails/407988-Joseph-S-Harris-and-the-U-S-Northwest-Boundary-Survey-1857-1861">letters of one expedition member</a> imply they were running low on cornmeal and supplementing their imported supplies by trading with locals. Although <a href="https://siarchives.si.edu/sites/all/modules/sia/sia_mirador/mirador/mirador_player3?manifest=https://iiif.si.edu/manifests/siarchives/SIA-007209_B01_F02_MODSI1328.json">Gibbs noted in his journal</a> that Mutton was ill before he died, there was no isotopic evidence to support chronic illness; Mutton may have become sick quickly.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/565265/original/file-20231212-23-zikxpo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Scientist with blue gloves uses a tool to lift a bit of hair from the pelt" src="https://images.theconversation.com/files/565265/original/file-20231212-23-zikxpo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/565265/original/file-20231212-23-zikxpo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/565265/original/file-20231212-23-zikxpo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/565265/original/file-20231212-23-zikxpo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/565265/original/file-20231212-23-zikxpo.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/565265/original/file-20231212-23-zikxpo.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/565265/original/file-20231212-23-zikxpo.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1005&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Chris Stantis carefully removes a minimal sample from Mutton’s pelt for further analyses.</span>
<span class="attribution"><span class="source">Hsiao-Lei Liu</span></span>
</figcaption>
</figure>
<p>Next, we turned to genetic analysis for insight into the dog’s ancestry to understand long-term management of this breed. We sequenced Mutton’s DNA and compared it with a contemporaneous village dog that was killed by the explorers in an unknown village in the Pacific Northwest. We also compared Mutton’s DNA with a genetic panel of many other modern and ancient dogs.</p>
<p><a href="https://doi.org/10.1126/science.adi6549">We found that Mutton</a> is a rare example of an Indigenous North American dog with precolonial ancestry who lived well after the arrival of white settlers. Using a dataset of mitochondrial genomes from Mutton and more than 200 ancient and modern dogs, we made an elaborate family tree. Called a <a href="http://dunnlab.org/phylogenetic_biology/phylogenies-and-time.html">time-calibrated phylogenetic tree</a>, it creates a diagram of the evolution of Mutton’s maternal lineage.</p>
<p>Based on the tree, we estimate that Mutton’s most recent common ancestor diverged from one other ancient dog from British Columbia between 1,800 and 4,800 years ago, corresponding with the known archaeological record. In other words, Mutton’s woolly dog lineage has been isolated from other dogs for millennia.</p>
<p>We see evidence of inbreeding in Mutton’s genome that can result only from careful long-term selective breed management. We identified variants of genes associated with hair and skin, including KRT77 and KANK2, which are linked to <a href="https://doi.org/10.1136/jmedgenet-2014-102346">woolly hair in humans</a>. </p>
<p>However, Mutton lived during a very volatile <a href="https://www.nps.gov/places/the-fraser-river-gold-rush.htm">time period</a>. For example, in 1858 more than 33,000 miners flooded into present-day British Columbia in <a href="https://www.thecanadianencyclopedia.ca/en/article/fraser-river-gold-rush">search of gold</a>. This influx left its mark in Mutton’s DNA, and we found that about one eighth of his genome – representating about one great-grandparent’s worth of DNA – came from settler-introduced European dogs. </p>
<p>Finally, we worked closely with a <a href="https://www.karencarr.com/">scientific artist</a>, using archaeological dog bones and Mutton’s pelt, to reconstruct what these dogs looked like in life with scientific accuracy.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/562506/original/file-20231129-21-3c76dg.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="zig-zag patterened blanket with fringe on three sides" src="https://images.theconversation.com/files/562506/original/file-20231129-21-3c76dg.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/562506/original/file-20231129-21-3c76dg.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=433&fit=crop&dpr=1 600w, https://images.theconversation.com/files/562506/original/file-20231129-21-3c76dg.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=433&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/562506/original/file-20231129-21-3c76dg.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=433&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/562506/original/file-20231129-21-3c76dg.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=544&fit=crop&dpr=1 754w, https://images.theconversation.com/files/562506/original/file-20231129-21-3c76dg.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=544&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/562506/original/file-20231129-21-3c76dg.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=544&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A Coast Salish classic-style blanket, which has woolly dog hair in the warp fibers that were stretched across the loom. Accessioned 1838-1842.</span>
<span class="attribution"><span class="source">USNM E2124, Smithsonian National Museum of Natural History</span></span>
</figcaption>
</figure>
<h2>What this woolly dog confirms about the past</h2>
<p>With Mutton’s pelt, our team wove together these different ways of exploring the many lives of Mutton – his ancestry as an Indigenous dog, his life traveling with white settlers, and finally his time in the Smithsonian Institution.</p>
<p>Mutton is the latest dog we’re aware of with that much precolonial dog ancestry. European colonization was devastating to Indigenous people in North America. The fact that Mutton carries as much Indigenous dog DNA as he does is a testament to the care that Coast Salish people took to keep the woolly dog tradition alive.</p>
<p>Our Coast Salish weaving collaborators are very keen to learn more about how traditional blankets housed in museum collections are made – to inform efforts to revive complex techniques and better understand the unique materials used. With Mutton’s genetic sequencing, future researchers may be able to identify dog hair in heritage woven materials. Some Coast Salish would like to see the woolly dogs return to their families once again. There’s currently no way to bring back the original woolly dogs, such as by cloning Mutton, because his DNA is far too degraded after more than 160 years. But a new kind of woolly dog could be created in the future through <a href="https://www.britannica.com/science/selective-breeding">selective breeding</a> and care.</p>
<p>“But the thing that’s most important (is) that (the) wool dog created a gift to produce and to make something, to create something, to bring something alive,” Michael Pavel, elder of the <a href="https://skokomish.org/culture-and-history/">Twana/Skokomish Tribe</a>, told us. “Let’s do that. Let’s bring that back to life. … The wool dog is still very much a part of our life.”</p><img src="https://counter.theconversation.com/content/217868/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Dogs have lived with Indigenous Americans since before they came to the continent together 10,000 years ago. A new analysis reveals the lineage of one 1800s ‘woolly dog’ from the Pacific Northwest.
Audrey T. Lin, Research Associate in Anthropology, Smithsonian Institution
Chris Stantis, Postdoctoral Research Fellow in Geology and Geophysics, University of Utah
Logan Kistler, Curator of Archaeobotany and Archaeogenomics, National Museum of Natural History, Smithsonian Institution
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/211589
2023-08-18T12:39:32Z
2023-08-18T12:39:32Z
Identifying fire victims through DNA analysis can be challenging − a geneticist explains what forensics is learning from archaeology
<figure><img src="https://images.theconversation.com/files/543315/original/file-20230817-17-h1y2zw.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C1024%2C683&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Identifying victims after a disaster can offer closure to loved ones.</span> <span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/APTOPIXHawaiiFires/2b2bf672bfc14794b8fbc20138f36c62">AP Photo/Jae C. Hong</a></span></figcaption></figure><p>Fire devastates communities and families, and it makes <a href="https://doi.org/10.1111/j.1556-4029.2012.02083.x">identification of victims challenging</a>. In the aftermath of the wildfire that swept through Lahaina, Hawaii, <a href="https://www.staradvertiser.com/2023/08/14/hawaii-news/maui-families-provide-dna-to-help-id-remains-of-fire-victims/">officials are collecting DNA samples</a> from relatives of missing persons in the hope that this can aid in identifying those who died in the fire. </p>
<p>But how well does DNA hold up under such extreme conditions, and what is the best way to recover DNA from fire victims? </p>
<p>I am an <a href="https://scholar.google.com/citations?user=xqKVKIwAAAAJ&hl=en">anthropological geneticist</a> who studies degraded DNA in archaeological and forensic contexts. <a href="https://stone.lab.asu.edu">My research group</a> applies ancient DNA and forensic analysis methods to optimize DNA recovery from burned bones. Retrieving DNA from severely burned remains in order to identify victims is a particular challenge.</p>
<h2>Forensic DNA analysis</h2>
<p>In a typical forensic investigation, <a href="https://www.forensicsciencesimplified.org/dna/how.html">DNA is extracted</a> from a sample – whether some blood, pieces of tissue or bone – collected from the scene of the disaster or crime. This process chemically separates the DNA from other components of cells within the sample, such as proteins, and purifies it. </p>
<p>This DNA is used as a template for <a href="https://www.genome.gov/about-genomics/fact-sheets/Polymerase-Chain-Reaction-Fact-Sheet">polymerase chain reaction, or PCR, analysis</a>, a method that is essentially the Xerox copier of molecular biology. Even if there are only a few cells present in the sample, PCR can amplify those DNA molecules into thousands or millions of copies. This creates a sufficient amount of DNA for subsequent tests.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/7onjVBsQwQ8?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">DNA analysis can help identify victims by comparing genetic similarities between people.</span></figcaption>
</figure>
<p>In forensics, the specific DNA targeted in PCR is usually a set of highly repetitive markers called <a href="https://strbase-archive.nist.gov/intro.htm">microsatellites, or short tandem repeats</a>. Law enforcement agencies around the world use specific sets of these markers for identification purposes. In the U.S., forensic analysts target 20 of these DNA repeats. Each person has two unique alleles, or genetic variants, at each of these markers, and these alleles are uploaded to the FBI’s <a href="https://www.fbi.gov/how-we-can-help-you/dna-fingerprint-act-of-2005-expungement-policy/codis-and-ndis-fact-sheet">Combined DNA Index System database</a> to identify matches. </p>
<p>DNA taken from the <a href="https://namus.nij.ojp.gov/services/dna#faq-what-is-a-family-reference-sample">relatives of missing people</a> will likely be analyzed for short tandem repeat markers and their allele profiles uploaded to the Relatives of Missing Persons index within the database. The expectation is that victims and their biological relatives share a percentage of alleles for these markers. For example, parents and children share 50% of their alleles, since a child inherits half of their DNA from each parent.</p>
<h2>Challenge of degraded DNA</h2>
<p>In forensic contexts, the time between death and DNA sampling is usually short enough that the DNA is often still in fairly good shape, both in terms of quantity and quality. However, DNA is often not found in ideal conditions after a disaster. </p>
<p>Time and the elements <a href="https://doi.org/10.1080/20961790.2018.1515594">take their toll</a>. After death, the process of decomposition releases enzymes that can cleave or damage DNA, and additional damage occurs over time depending on the environment in which the body is found. DNA also degrades faster in warm, wet, acidic environments and slower in colder, drier environments that are more pH neutral or slightly basic. </p>
<p>In addition, DNA preservation may vary considerably among the tissues, bones and teeth recovered. For example, researchers found that DNA identification of victims of the <a href="https://doi.org/10.1111/j.1556-4029.2009.01045.x">World Trade Center attacks</a> in 2001 was most successful when using bones of the feet and legs, compared with bones from the head and torso.</p>
<p>DNA damage can take different forms. Nicks and breaks in the DNA make it difficult to analyze. Chemical modification of the DNA can result in changes to the original sequence or make it unreadable. This includes changes to the building blocks of DNA <a href="https://www.genome.gov/genetics-glossary/Nucleotide">called nucleotides</a> that make up an identifiable sequence. For example, exposure to water can cause a chemical reaction <a href="https://doi.org/10.1101/cshperspect.a012567">called deamination</a> that changes the nucleotide cytosine such that it appears to be the nucleotide thymine upon analysis. Exposures to other chemicals or UV light can <a href="https://chem.libretexts.org/Ancillary_Materials/Exemplars_and_Case_Studies/Exemplars/Biology/Cross-Linking_in_DNA">cause cross-linking</a>, which essentially ties the DNA into knots. As a result, the PCR enzymes used to copy or read the DNA sequence can’t move linearly along the DNA strand. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/543323/original/file-20230817-33902-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Rows of burnt houses and cars in the aftermath of the Lahaina fires." src="https://images.theconversation.com/files/543323/original/file-20230817-33902-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543323/original/file-20230817-33902-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543323/original/file-20230817-33902-1dr1ti.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543323/original/file-20230817-33902-1dr1ti.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543323/original/file-20230817-33902-1dr1ti.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543323/original/file-20230817-33902-1dr1ti.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543323/original/file-20230817-33902-1dr1ti.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Exposure to intense and extended fires can make victim identification through DNA analysis difficult.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/HawaiiFires/185896ea7dfd43b99850521649cf5be6">AP Photo/Jae C. Hong</a></span>
</figcaption>
</figure>
<h2>Applying methods from archaeology</h2>
<p>Researchers encounter similar issues in handling degraded genetic material when analyzing the DNA of ancient remains that are thousands of years old. To address these challenges, forensic geneticists and ancient DNA researchers like me employ a number of tricks to <a href="https://doi.org/10.1038/s43586-020-00011-0">optimize DNA retrieval</a>.</p>
<p>First, we tend to target dense bone or teeth for sampling, since they are more impervious to the environment. We also use DNA extraction methods that enhance the recovery of short fragments of DNA. </p>
<p>Second, we use PCR to amplify even shorter genetic markers, including mini-short tandem repeats, or sections of the <a href="https://www.genome.gov/genetics-glossary/Mitochondrial-DNA">mitochondrial genome</a>. Mitochondria are structures within each cell that produce energy, and each one has its own DNA. Mitochondrial DNA is passed down from mother to child and can be found in hundreds of copies within each mitochondrion, which make it easier to recover and analyze. However, mitochondrial DNA <a href="https://doi.org/10.1146/annurev.genom.4.070802.110352">may not provide sufficient information</a> for identification, since people who are maternally related, even very distantly, will share the same sequence.</p>
<p>Researchers are also testing newer methods of DNA analysis common in the ancient DNA field for forensic purposes. For example, <a href="https://doi.org/10.1038/s43586-020-00011-0">special enzymes</a> can remove chemically modified nucleotides, such as deaminated cytosines, to prevent misreading of the DNA sequence. Researchers can also use DNA baits to “fish” for specific sequences. This method of <a href="https://doi.org/10.1038/nmeth.1419">targeted enrichment</a> can recover very small fragments that can be used to piece together the full genetic sequence.</p>
<h2>DNA analysis of burned remains</h2>
<p>For <a href="https://doi.org/10.1002/9781119682691.ch12">fire victims</a>, particularly those caught in intense, extended fires, the DNA may be highly fragmented, making analysis difficult. High temperatures cause bonds between molecules, including nucleotides, to break. This results in fragmentation and ultimately destruction of the DNA.</p>
<p>Because hard tissue – bones and teeth – are often all that remains after a fire, forensic researchers have studied how bone characteristics such as color and composition <a href="https://doi.org/10.1016/j.fsigen.2010.08.008">change with temperature</a>. My research team used this information to classify the level of burning that human bone samples have been subjected to.</p>
<p>In investigating DNA preservation in those samples, we found that there is a <a href="https://doi.org/10.1016/j.fsigen.2020.102272">significant point of DNA degradation</a> when bones reached temperatures between 662 degrees Fahrenheit (350 degrees Celsius) and 1,022 F (550 C). For comparison, <a href="https://www.cremationassociation.org/page/CremationProcess">commercial cremation</a> is 1,400 to 1,600 F (760 to 871 C) for 30 to 120 minutes, and <a href="https://doi.org/10.1016/j.csite.2017.08.001">vehicle fires</a> typically reach 1,652 degrees F (900 C) but can last a shorter period of time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/543318/original/file-20230817-25-qy54jc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="People walking down street past the rubble of wildfire damage in Lahaina" src="https://images.theconversation.com/files/543318/original/file-20230817-25-qy54jc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/543318/original/file-20230817-25-qy54jc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/543318/original/file-20230817-25-qy54jc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/543318/original/file-20230817-25-qy54jc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/543318/original/file-20230817-25-qy54jc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/543318/original/file-20230817-25-qy54jc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/543318/original/file-20230817-25-qy54jc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Survivors of the Lahaina wildfires, which began on Aug. 8, 2023, walk through the aftermath.</span>
<span class="attribution"><a class="source" href="https://newsroom.ap.org/detail/HawaiiFiresPowerLines/6643e5e332e44e8e8fedbb01c15ece9c">AP Photo/Rick Bowmer</a></span>
</figcaption>
</figure>
<p>Our team also found that the likelihood of generating high-quality short tandem repeat data or mitochondrial DNA sequence data, whether using forensic or ancient DNA methods, decreases significantly at temperatures <a href="https://doi.org/10.1016/j.fsigen.2021.102610">greater than 1,022 F</a> (550 C). </p>
<p>In sum, as temperature and exposure time increase, the amount of remaining DNA decreases. This leads to only partial DNA profiles, which can limit analysts’ ability to match a victim to a relative with high statistical certainty or prevent results altogether.</p>
<p>DNA evidence is not the only method used for identification. Investigators <a href="https://doi.org/10.1016/j.forsciint.2008.09.019">combine DNA with other evidence</a> – such as dental, skeletal and contextual information – to identify a victim conclusively. Together, this information hopefully will help bring closure for families and friends.</p><img src="https://counter.theconversation.com/content/211589/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anne Stone receives funding from the National Institute of Justice. </span></em></p>
Maui officials have asked relatives to provide DNA samples to help identify victims of the Lahaina wildfires. Time and exposure to the elements, however, can make DNA retrieval from remains difficult.
Anne Stone, Professor of Human Evolution and Social Change, Arizona State University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/208909
2023-08-03T18:01:18Z
2023-08-03T18:01:18Z
Cats first finagled their way into human hearts and homes thousands of years ago – here’s how
<figure><img src="https://images.theconversation.com/files/541015/original/file-20230803-19-fmuwe.jpg?ixlib=rb-1.1.0&rect=10%2C0%2C6647%2C4626&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Who run the world? Cats!</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/black-cat-stretches-on-rug-in-bedroom-royalty-free-image/1402118614">Grace Cary/Moment via Getty Images</a></span></figcaption></figure><p>A few years ago, I had the opportunity to go on safari in southern Africa. One of the greatest thrills was going out at night looking for predators on the prowl: lions, leopards, hyenas.</p>
<p>As we drove through the darkness, though, our spotlight occasionally lit up a smaller hunter – a slender, tawny feline, faintly spotted or striped. The glare would catch the small cat for a moment before it darted back into the shadows.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/540798/original/file-20230802-25-fqa49r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="long-legged, striped cat peeks out of scrubby greens" src="https://images.theconversation.com/files/540798/original/file-20230802-25-fqa49r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/540798/original/file-20230802-25-fqa49r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=900&fit=crop&dpr=1 600w, https://images.theconversation.com/files/540798/original/file-20230802-25-fqa49r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=900&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/540798/original/file-20230802-25-fqa49r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=900&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/540798/original/file-20230802-25-fqa49r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1131&fit=crop&dpr=1 754w, https://images.theconversation.com/files/540798/original/file-20230802-25-fqa49r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1131&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/540798/original/file-20230802-25-fqa49r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1131&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">An African wildcat doesn’t look so different from a domestic cat.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/african-wildcat-falbkatze-felis-lybica-african-wild-royalty-free-image/494894455">pum_eva/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<p>Based on its size and appearance, I initially presumed it was someone’s pet inexplicably out in the bush. But further scrutiny revealed distinctive features: legs slightly longer than those of most domestic cats, and a striking black-tipped tail. Still, if you saw one from your kitchen window, your first thought would be “Look at that beautiful cat in the backyard,” not “How’d that African wildcat get to New Jersey?”</p>
<p><a href="https://scholar.google.com/citations?user=G4Np3c0AAAAJ&hl=en&oi=ao">As an evolutionary biologist</a>, I’ve spent my career <a href="https://www.jonathanlosos.com/research">studying how species adapt to their environment</a>. My research has been reptile-focused, investigating the workings of <a href="https://www.britannica.com/science/natural-selection">natural selection</a> on lizards.</p>
<p>Yet, I’ve always loved and been fascinated by felines, ever since we adopted a shelter cat when I was 5 years old. And the more I’ve thought about those African wildcats, the more I’ve marveled at their evolutionary success. The species’ claim to fame is simple: The <a href="https://doi.org/10.1126/science.1139518">African wildcat is the ancestor</a> of our beloved household pets. And despite changing very little, their descendants have become among the world’s two most popular companion animals. (Numbers are fuzzy, but the global population of <a href="https://media.nature.com/original/magazine-assets/d41586-018-01018-0/d41586-018-01018-0.pdf">cats</a> and <a href="https://www.wellbeingintlstudiesrepository.org/wbn/vol2/iss5/1/">dogs</a> approaches a billion for each.)</p>
<p>Clearly, the few evolutionary changes the domestic cat has made have been the right ones to wangle their way into people’s hearts and homes. How did they do it? I explored this question in my book “<a href="https://www.penguinrandomhouse.com/books/610619/the-cats-meow-by-jonathan-b-losos/">The Cat’s Meow: How Cats Evolved from the Savanna to Your Sofa</a>.”</p>
<h2>Why the African wildcat?</h2>
<p>Big cats – like lions, tigers and pumas – are the attention-grabbing celebrities of the feline world. But of the <a href="https://en.wikipedia.org/wiki/List_of_felids">41 species of wild felines</a>, the vast majority are about the size of a housecat. Few people have heard of the black-footed cat or the Borneo bay cat, much less the kodkod, oncilla or marbled cat. Clearly, the little-cat side of the feline family needs a better PR agent.</p>
<p>In theory, any of these species could have been the progenitor of the domestic cat, but <a href="https://doi.org/10.1126/science.1139518">recent DNA studies demonstrate unequivocally</a> that today’s housecats arose from the African wildcat – specifically, the North African subspecies, <em>Felis silvestris lybica</em>.</p>
<p>Given the profusion of little pusses, why was the North African wildcat the one to give rise to our household companions?</p>
<p>In short, it was the right species in the right place at the right time. <a href="https://www.britannica.com/place/Mesopotamia-historical-region-Asia">Civilization began</a> in the <a href="https://www.britannica.com/place/Fertile-Crescent">Fertile Crescent</a> about 10,000 years ago, when people first settled into villages and started growing food.</p>
<p>This area – spanning parts of modern-day Egypt, Turkey, Syria, Iran and more – is <a href="https://en.wikipedia.org/wiki/List_of_felids">home to numerous small cats</a>, including the caracal, serval, jungle cat and sand cat. But of these, the African wildcat is the one that to this day enters villages and <a href="https://www.saveacat.org/african-wildcats.html">can be found around humans</a>. </p>
<p>African wildcats are among the friendliest of feline species; raised gently, they <a href="https://www.hachettebookgroup.com/titles/john-bradshaw/cat-sense/9780465064960/">can make affectionate companions</a>. In contrast, despite the most tender attention, their close relative the European wildcat <a href="https://www.hachettebookgroup.com/titles/john-bradshaw/cat-sense/9780465064960/">grows up to be hellaciously mean</a>.</p>
<p>Given these tendencies, it’s easy to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5790555/">envision what likely happened</a>. People settled down and started raising crops, storing the excess for lean times. These granaries led to rodent population explosions. Some African wildcats – those with the least fear of humans – took advantage of this bounty and started hanging around. People saw the benefit of their presence and treated the cats kindly, perhaps giving them shelter or food. The boldest cats entered huts and perhaps allowed themselves to be petted – kittens are adorable! – and, voilà, the domestic cat was born.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/541018/original/file-20230803-15-fpyrml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Mummy of a cat wrapped in material with an X-ray image of the skeleton inside" src="https://images.theconversation.com/files/541018/original/file-20230803-15-fpyrml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/541018/original/file-20230803-15-fpyrml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=1030&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541018/original/file-20230803-15-fpyrml.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=1030&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541018/original/file-20230803-15-fpyrml.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=1030&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541018/original/file-20230803-15-fpyrml.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1294&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541018/original/file-20230803-15-fpyrml.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1294&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541018/original/file-20230803-15-fpyrml.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1294&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Egyptian mummified cat.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/mummified-cat-from-egypt-dated-2493-bc-news-photo/590674867">Universal History Archive/Universal Images Group via Getty Images</a></span>
</figcaption>
</figure>
<p>Where exactly domestication occurred – if it was a single place and not simultaneously throughout the entire region – is unclear. But <a href="https://mymodernmet.com/cats-in-ancient-egyptian-art/">tomb paintings and sculptures</a> show that by 3,500 years ago, domestic cats lived in Egypt. <a href="https://doi.org/10.1038/s41437-022-00568-4">Genetic analysis</a> – including <a href="https://doi.org/10.1038/s41559-017-0139">DNA from Egyptian cat mummies</a> – and archaeological data chart the feline diaspora. They moved northward through Europe (and ultimately to North America), south deeper into Africa and eastward to Asia. Ancient DNA even demonstrates that <a href="https://doi.org/10.1038/s41559-017-0139">Vikings played a role in spreading felines</a> far and wide.</p>
<h2>What cat traits did domestication emphasize?</h2>
<p>Domestic cats possess many colors, patterns and hair textures not seen in wildcats. Some <a href="https://cfa.org/">cat breeds</a> have distinctive physical features, like <a href="https://www.tica.org/breeds/browse-all-breeds?view=article&id=857:munchkin-breed&catid=79">munchkins’ short legs</a>, <a href="https://cfa.org/siamese/">Siameses’ elongated faces</a> or <a href="https://cfa.org/persian/">Persians’ lack of muzzle</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/541021/original/file-20230803-19-s56je1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="closeup of a fluffy gray cat's face with a flat smooshed face" src="https://images.theconversation.com/files/541021/original/file-20230803-19-s56je1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541021/original/file-20230803-19-s56je1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=474&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541021/original/file-20230803-19-s56je1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=474&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541021/original/file-20230803-19-s56je1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=474&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541021/original/file-20230803-19-s56je1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=595&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541021/original/file-20230803-19-s56je1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=595&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541021/original/file-20230803-19-s56je1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=595&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A fluffy, flat-faced Persian cat has changed a lot in looks from its wildcat ancestor.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/flossie-a-persian-cat-is-groomed-during-the-shropshire-cat-news-photo/1463247867">Shirlaine Forrest via Getty Images</a></span>
</figcaption>
</figure>
<p>Yet many domestics appear basically indistinguishable from wildcats. In fact, only <a href="https://doi.org/10.1073/pnas.1410083111">13 genes have been changed by natural selection</a> during the domestication process. By contrast, <a href="https://doi.org/10.1038/nature11837">almost three times as many genes changed</a> during the descent of dogs from wolves.</p>
<p>There are only two ways to indisputably identify a wildcat. You can measure the size of its brain – <a href="https://doi.org/10.1007/978-3-642-70877-0_13">housecats</a>, <a href="https://doi.org/10.3998/jar.0521004.0068.201">like other domestic animals</a>, have evolved reductions in the parts of the brain associated with aggression, fear and overall reactivity. Or you can measure the length of its intestines – <a href="https://doi.org/10.1111/j.1439-0469.2009.00537.x">longer in domestic cats</a> to digest vegetable-based food provided by or scavenged from humans.</p>
<p>The most significant evolutionary changes during cat domestication involve their behavior. The common view that domestic cats are aloof loners couldn’t be further from the truth. When lots of domestic cats live together – in places where humans provide copious amounts of food – <a href="https://www.researchgate.net/publication/266757891_Group-living_in_the_Domestic_Cat_Its_Sociobiology_and_Epidemiology">they form social groups very similar to lion prides</a>. Composed of related females, these cats are very friendly – grooming, playing with and lying on top of each other, nursing each other’s kittens, even serving as midwives during birth.</p>
<p>To signal friendly intentions, <a href="https://gwern.net/doc/cat/psychology/2000-bradshaw.pdf">an approaching cat raises its tail straight up</a>, a trait shared with lions and no other feline species. As anyone who has lived with a cat knows, they use this “I want to be friends” message toward people as well, indicating that they include us in their social circle.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/541024/original/file-20230803-29-bnot80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="orange cat stretches toward tabletop where woman grates cheese" src="https://images.theconversation.com/files/541024/original/file-20230803-29-bnot80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541024/original/file-20230803-29-bnot80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541024/original/file-20230803-29-bnot80.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541024/original/file-20230803-29-bnot80.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541024/original/file-20230803-29-bnot80.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541024/original/file-20230803-29-bnot80.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541024/original/file-20230803-29-bnot80.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cats use plenty of tools and tricks to get you to hand over what they want.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/ginger-cat-begs-food-in-the-kitchen-while-cooking-royalty-free-image/1219723659">Nail Galiev/iStock via Getty Images Plus</a></span>
</figcaption>
</figure>
<h2>Evolution of a master manipulator</h2>
<p>Household cats are quite vocal to their human companions, using <a href="https://gwern.net/doc/cat/psychology/2003-nicastro.pdf">different meows to communicate different messages</a>. Unlike the tail-up display, however, this is not an example of their treating us as part of their clan. Quite the contrary, <a href="https://gwern.net/doc/cat/psychology/2000-bradshaw.pdf">cats rarely meow to one another</a>.</p>
<p>The sound of these meows has <a href="https://doi.org/10.1037/0735-7036.118.3.287">evolved during domestication</a> to more effectively communicate with us. Listeners rate the wildcat’s call as more urgent and demanding (“Mee‑O‑O‑O‑O‑O‑W!”) compared with the domestic cat’s more pleasing (“MEE‑ow”). Scientists suggest that these shorter, higher-pitched sounds are <a href="https://doi.org/10.1037/0735-7036.118.3.287">more pleasing to our auditory system</a>, perhaps because young humans have high-pitched voices, and domestic cats have evolved accordingly to curry human favor.</p>
<p>Cats similarly <a href="https://doi.org/10.1016/j.cub.2009.05.033">manipulate people with their purrs</a>. When they want something – picture a cat rubbing against your legs in the kitchen while you open a can of wet food – they purr extra loudly. And this purr is not the agreeable thrumming of a content cat, but an insistent chainsaw br-rr-oom demanding attention.</p>
<p>Scientists digitally compared the spectral qualities of the <a href="https://www.sciencedirect.com/science/article/pii/S0960982209011683#app2">two types of purrs</a> and discovered that the major difference is that the insistent purr includes a component very similar to the sound of a human baby crying. People, of course, are <a href="https://doi.org/10.1111/j.1651-2227.2011.02554.x">innately attuned to this sound</a>, and cats have evolved to take advantage of this sensitivity to get our attention.</p>
<p>Of course, that won’t surprise anyone who’s lived with a cat. <a href="https://www.hachettebookgroup.com/titles/john-bradshaw/the-trainable-cat/9780465093717/">Although cats are very trainable</a> – they’re very food motivated – cats usually train us more than we train them. As the old saw goes, “Dogs have owners, cats have staff.”</p><img src="https://counter.theconversation.com/content/208909/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jonathan Losos recently published a book, "The Cat's Meow," on the topic of this essay.</span></em></p>
Natural selection changed just 13 genes to separate your Felix and Fluffy from their African wildcat ancestor.
Jonathan Losos, William H. Danforth Distinguished University Professor, Arts & Sciences at Washington University in St. Louis
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/210056
2023-07-19T20:00:03Z
2023-07-19T20:00:03Z
Ancient DNA reveals the earliest evidence of the last massive human migration to Western Europe
<p>Nomadic animal-herders from the Eurasian steppe mingled with Copper Age farmers in southeastern Europe centuries earlier than previously thought. </p>
<p>In a new study <a href="https://www.nature.com/articles/s41586-023-06334-8">published in Nature</a>, we used ancient DNA to gain new insights into the spread of culture, technologies and ancestry at a crucial juncture in European history.</p>
<h2>How ancient DNA can help us understand change</h2>
<p>Humanity’s archaeological record reveals massive changes in cultural practices and <a href="https://theconversation.com/how-a-handful-of-prehistoric-geniuses-launched-humanitys-technological-revolution-171511">technologies</a>. </p>
<p>However, it is not always clear how these changes moved between different groups of people. It can happen either by a spread of ideas (such as through trade), or through the migration of people.</p>
<p>In Europe, there have been <a href="https://theconversation.com/european-invasion-dna-reveals-the-origins-of-modern-europeans-38096">two major migrations</a> in the past 10,000 years. </p>
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Read more:
<a href="https://theconversation.com/european-invasion-dna-reveals-the-origins-of-modern-europeans-38096">European invasion: DNA reveals the origins of modern Europeans</a>
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<p>First, there was an expansion of early farming groups from Anatolia around 9,000 years ago. This was associated with the introduction of farming practices and animal husbandry, a more sedentary lifestyle (permanent housing) and the wide use of pottery and new types of polished stone tools.</p>
<p>Second was the expansion of steppe herders from the <a href="https://www.oneearth.org/ecoregions/pontic-steppe/">Eurasian Pontic Steppes</a> around 5,000 years ago. This is associated with the spread of pastoralism and dairying technologies, a different type of ancestry and possibly some of the Indo-European languages.</p>
<p>In our <a href="https://www.nature.com/articles/s41586-023-06334-8">new research</a>, we studied the interaction between farming and pastoralist groups from the steppe from a new angle by analysing the genomes of 135 individuals from southeastern Europe and the northwestern Black Sea region, who lived between 4,000 and 7,000 years ago. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/538000/original/file-20230718-21-739xyt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map showing the Black Sea and surrounding areas." src="https://images.theconversation.com/files/538000/original/file-20230718-21-739xyt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/538000/original/file-20230718-21-739xyt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=380&fit=crop&dpr=1 600w, https://images.theconversation.com/files/538000/original/file-20230718-21-739xyt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=380&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/538000/original/file-20230718-21-739xyt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=380&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/538000/original/file-20230718-21-739xyt.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=477&fit=crop&dpr=1 754w, https://images.theconversation.com/files/538000/original/file-20230718-21-739xyt.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=477&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/538000/original/file-20230718-21-739xyt.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=477&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The area around Odesa was a ‘melting pot’ of cultures and ancestries.</span>
<span class="attribution"><span class="source">Modified from Penske et al. (2023)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We uncovered previously unknown and significant genetic changes in the people living in these regions. We also found the presence of steppe ancestry in the contact zone in the northwestern Black Sea region around 5,500 years ago, some 500 years earlier than previously assumed. </p>
<h2>The Copper Age in southeastern Europe</h2>
<p>Southeastern Europe played an important role in the spread of farming across Europe after early farmers from Anatolia arrived around 9,000-8,000 years ago. Approximately 1,000 years later, easy access to copper, gold and salt led to the development of <a href="https://doi.org/10.1177/1461957107086121">many flourishing settlements</a> in parts of today’s Bulgaria and Romania. </p>
<p>Settlements on the Black Sea and major rivers such as the Danube thrived through contact and trade with surrounding areas. Similarity in material culture visible in the archaeological record across a wider region indicates a period of social and political stability of approximately 500 years, between around 6,200 and 6,700 years ago.</p>
<p>Ninety-five of the ancient genomes we analysed were from this period and region, and this cultural similarity and stability is reflected in the absence of major genetic differences. </p>
<h2>A new era and a melting pot of human interaction</h2>
<p>Following this period of stability, many Copper Age settlements were abruptly abandoned around 6,000 years ago. For almost the next 1,000 years so few people lived in southeastern Europe that the period is often referred to as “the dark millennium”. The reason for this is not fully understood, but it is likely due to the depletion of resources due to unfavourable climatic conditions. </p>
<p>Instead, large settlements of several thousand houses emerged further north in parts of what are now Moldova and Ukraine. Located on the western end of the forest steppe zone, these mega-sites were associated with the <a href="https://doi.org/10.1007/s10963-017-9105-8">Cucuteni-Trypillia culture</a>. </p>
<p>Here, during a period called the Eneolithic spanning from 5,200 to 6,500 years ago, the region around today’s Odesa became a “melting pot” of human interaction. Numerous cultural influences appear in the archaeological record, including the waning Copper Age cultures and the Cucuteni-Trypillia culture. </p>
<p>Interestingly, the resulting style of pottery and other artefacts at the mega-sites showed influences from two additional groups. First, from nearby groups that could be traced to the steppe region east of Odesa. Second, from the distant Maykop culture of the North Caucasus, a mountain range east of the Black Sea. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/537927/original/file-20230718-20840-oyfm8y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Many photos of jewellery, weapons, tools and pots shown on a white background." src="https://images.theconversation.com/files/537927/original/file-20230718-20840-oyfm8y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/537927/original/file-20230718-20840-oyfm8y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=931&fit=crop&dpr=1 600w, https://images.theconversation.com/files/537927/original/file-20230718-20840-oyfm8y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=931&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/537927/original/file-20230718-20840-oyfm8y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=931&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/537927/original/file-20230718-20840-oyfm8y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1170&fit=crop&dpr=1 754w, https://images.theconversation.com/files/537927/original/file-20230718-20840-oyfm8y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1170&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/537927/original/file-20230718-20840-oyfm8y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1170&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Characteristic jewellery, weapons, tools and pottery from the melting pot area around today’s Odesa. The pottery combines characteristics from numerous cultures of the area.</span>
<span class="attribution"><span class="source">I. Manzura (2020), History Carved by the Dagger: the Society of the Usatovo Culture in the 4th Millennium BC</span></span>
</figcaption>
</figure>
<p>The steppe groups practised a different way of life, called nomadic pastoralism. Where farmers lived on and worked the same piece of land, nomadic pastoralists kept moving to find fresh pastures for their large herds of animals.</p>
<p>On top of this very different lifestyle, they also carried a distinct genetic profile called “steppe ancestry”.</p>
<h2>A surprising discovery</h2>
<p>By analysing the genomes of 18 ancient individuals from the Odesa region from this period, we could see genetic evidence of the many cultural influences observed by archaeologists. </p>
<p>In addition to the previously observed Copper Age ancestry, we detected new genetic contributions from individuals from the forest steppe regions, and the North Caucasus. This new ancestry and its appearance in western Europe had been uniquely associated with the spread of a later cultural group known as the Yamnaya. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-a-handful-of-prehistoric-geniuses-launched-humanitys-technological-revolution-171511">How a handful of prehistoric geniuses launched humanity's technological revolution</a>
</strong>
</em>
</p>
<hr>
<p>This was a huge surprise. We didn’t expect to see signs of this ancestry until at least 500 years later, when the Yamnaya arrived.</p>
<p>These findings show there was not only a cultural exchange between the different groups. There must have also been biological interactions of many genetically distinct people coming together in this contact zone as early as 5,400 to 6,500 years ago. </p>
<p>Due to this “melting pot” the Eneolithic was characterised by a number of innovations. Technologies such as wheels, wagon transportation and improved metal-working spread quickly into western Europe and Central Asia.</p>
<h2>A mosaic of ancestries</h2>
<p>We also analysed 21 individuals from the Early Bronze Age, approximately 4,000–5,300 years ago. In eight of these individuals we observed the expected westward expansion of steppe pastoralists, this time associated with <a href="https://doi.org/10.1038/nature14317">the Yamnaya culture</a>. </p>
<p>This final migration brought with it the last part of the modern Western European gene pool, likely emerging from the preceding period of contact and exchange that we identified. However, the remaining 13 individuals retained the genetic signature from the preceding Copper Age. These findings indicated a coexistence of these genetically distinct peoples. </p>
<p>Our study of genetic data over time reveals a highly dynamic picture of human prehistory in southeastern Europe. As more ancient DNA data becomes available, so too will more chapters of this story.</p><img src="https://counter.theconversation.com/content/210056/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Ancient DNA from Ukraine uncovers the earliest evidence of the arrival of the ‘steppe ancestry’ – the last piece of the modern Western European genetic puzzle.
Adam "Ben" Rohrlach, Mathematics Lecturer and Ancient DNA Researcher, University of Adelaide
Sandra Penske, PhD Student, Max Planck Institute for Evolutionary Anthropology
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/204888
2023-05-04T19:06:29Z
2023-05-04T19:06:29Z
Reconstructing ancient bacterial genomes can revive previously unknown molecules – offering a potential source for new antibiotics
<figure><img src="https://images.theconversation.com/files/523906/original/file-20230502-2182-swsnio.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C8256%2C5499&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ancient DNA preserved in the tooth tartar of human fossils encodes microbial metabolites that could be the next antibiotic.</span> <span class="attribution"><a class="source" href="https://www.eurekalert.org/multimedia/983784?">Werner/Siemens Foundation</a></span></figcaption></figure><p>Microorganisms – in particular bacteria – are skillful chemists that can produce an impressive diversity of chemical compounds known as <a href="https://theconversation.com/nature-is-the-worlds-original-pharmacy-returning-to-medicines-roots-could-help-fill-drug-discovery-gaps-176963">natural products</a>. These metabolites provide the microbes major evolutionary advantages, such as allowing them to interact with one another or their environment and helping defend against different threats. Because of the diverse functions bacterial natural products have, many have been <a href="https://doi.org/10.1021/acs.jnatprod.5b01055">used as medical treatments</a> such as antibiotics and anti-cancer drugs.</p>
<p>The microbial species alive today represent only a tiny fraction of the vast diversity of microbes that have inhabited Earth over the past <a href="https://theconversation.com/were-viruses-around-on-earth-before-living-cells-emerged-a-microbiologist-explains-197880">3 billion years</a>. Exploring this microbial past presents exciting opportunities to recover some of their lost chemistry. </p>
<p>Directly studying these metabolites in archaeological samples is virtually impossible because of their <a href="https://doi.org/10.1007/s11306-017-1270-3">poor preservation</a> over time. However, reconstructing them using the genetic blueprints of long-dead microbes could provide a path forward. </p>
<p>We are a team of <a href="https://scholar.google.com/citations?user=cDFcc3cAAAAJ&hl=en">anthropologists</a>, <a href="https://scholar.google.de/citations?user=trnMQ7MAAAAJ&hl=en">archaeogeneticists</a> and <a href="https://scholar.google.com/citations?user=26MgwRgAAAAJ&hl=en">biochemists</a> who study ancient microbes. By <a href="https://www.science.org/doi/10.1126/science.adf5300">generating previously unknown chemical compounds</a> from the reconstructed genomes of ancient bacteria, our newly published research provides a proof of concept for the potential use of fossil microbes as a source of new drugs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/524480/original/file-20230504-17-ivzxrf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Researcher weighing tooth fossil on a scale" src="https://images.theconversation.com/files/524480/original/file-20230504-17-ivzxrf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524480/original/file-20230504-17-ivzxrf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=565&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524480/original/file-20230504-17-ivzxrf.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=565&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524480/original/file-20230504-17-ivzxrf.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=565&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524480/original/file-20230504-17-ivzxrf.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=710&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524480/original/file-20230504-17-ivzxrf.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=710&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524480/original/file-20230504-17-ivzxrf.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=710&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A single ancient tooth preserves the genomes of millions of ancient bacteria.</span>
<span class="attribution"><span class="source">Felix Wey/Werner Siemens Foundation</span></span>
</figcaption>
</figure>
<h2>Reconstructing ancient genomes</h2>
<p>The cellular machinery producing bacterial natural products is encoded in genes that are typically in close proximity to one another, forming what are called <a href="https://doi.org/10.1016/j.tim.2016.07.006">biosynthetic gene clusters</a>. Such genes are difficult to detect and reconstruct from ancient DNA because very old genetic material breaks down over time, fragmenting into thousands or even millions of pieces. The end result is numerous tiny DNA fragments <a href="https://doi.org/10.1038/s43586-020-00011-0">less than 50 nucleotides long</a> all mixed together like a jumbled jigsaw puzzle.</p>
<p>We sequenced billions of such ancient DNA fragments, then improved a bioinformatic process called <a href="https://doi.org/10.1007/s40484-019-0166-9">de novo assembly</a> to digitally order the ancient DNA fragments in stretches of up to 100,000 nucleotides long – a 2,000-fold improvement. This process allowed us to identify not only what genes were present, but also their order in the genome and the ways they differ from bacterial genes known today – key information to uncovering their evolutionary history and function. </p>
<p>This method allowed us to take an unprecedented look at the genomes of microbes living up to 100,000 years ago, including species not known to exist today. Our findings push back the <a href="https://doi.org/10.1038/s41586-021-03532-0">previously oldest</a> <a href="https://doi.org/10.1186/s40168-021-01132-8">reconstructed microbial genomes</a> by more than 90,000 years.</p>
<p>In the microbial genomes we reconstructed from DNA extracted from ancient tooth tartar, we found a gene cluster that was shared by a high proportion of Neanderthals and anatomically modern humans living during the <a href="https://www.britannica.com/event/Stone-Age/Middle-Paleolithic">Middle and Upper Paleolithic</a> that lasted from 300,000 to 12,000 years ago. This cluster bore the <a href="https://doi.org/10.1038/s43586-020-00011-0">molecular hallmarks of very ancient DNA</a> and belonged to the bacterial genus <em>Chlorobium</em>, a group of green sulfur bacteria capable of photosynthesis.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/524154/original/file-20230503-26-5xqprb.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Chemical structure of paleofurans produced using ancient microbial DNA." src="https://images.theconversation.com/files/524154/original/file-20230503-26-5xqprb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/524154/original/file-20230503-26-5xqprb.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=280&fit=crop&dpr=1 600w, https://images.theconversation.com/files/524154/original/file-20230503-26-5xqprb.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=280&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/524154/original/file-20230503-26-5xqprb.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=280&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/524154/original/file-20230503-26-5xqprb.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=351&fit=crop&dpr=1 754w, https://images.theconversation.com/files/524154/original/file-20230503-26-5xqprb.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=351&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/524154/original/file-20230503-26-5xqprb.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=351&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">These paleofurans were produced from ancient microbial DNA.</span>
<span class="attribution"><span class="source">Pierre Stallforth</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>We inserted a synthetic version of this gene cluster into a “modern” bacterium called <em>Pseudomona protegens</em> so it could produce the chemical compounds encoded in the ancient genes. Using this method, we were able to isolate two previously unknown compounds we named <a href="https://www.science.org/doi/10.1126/science.adf5300">paleofuran A and B</a> and determine their chemical structure. Resynthesizing these molecules in the lab from scratch confirmed their structure and allowed us to produce larger quantities for further analysis.</p>
<p>By reconstructing these ancient compounds, our findings highlight how archaeological samples could serve as new sources of natural products. </p>
<h2>Mining ancient natural products</h2>
<p>Microbes are constantly evolving and adapting to their surrounding environment. Because the environments they inhabit today differ from those of their ancestors, microbes today likely produce different natural products than ancient microbes from tens of thousands of years ago.</p>
<p>As recently as <a href="https://www.doi.org/10.1007/978-1-4613-1145-4_1">25,000 to 10,000 years ago</a>, the Earth underwent a major climate shift as it transitioned from the colder and more volatile <a href="https://www.britannica.com/science/Pleistocene-Epoch">Pleistocene Epoch</a> to the warmer and more temperate <a href="https://www.britannica.com/science/Holocene-Epoch">Holocene Epoch</a>. Human lifestyles also dramatically changed over this transition as people began living outside of caves and increasingly experimented with food production. These changes brought them into contact with different microbes through agriculture, animal husbandry and their new built environments. Studying Pleistocene-era bacteria may yield insights into bacterial species and biosynthetic genes no longer associated with humans today, and perhaps even microbes that have gone extinct.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/JfX06NINZpk?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Changes in human lifestyles changed our genomes.</span></figcaption>
</figure>
<p>While the amount of data collected by scientists on biological organisms has exponentially increased over the past few decades, the <a href="https://theconversation.com/antibiotic-resistance-is-at-a-crisis-point-government-support-for-academia-and-big-pharma-to-find-new-drugs-could-help-defeat-superbugs-169443">number of new antibiotics has stagnated</a>. This is particularly problematic when bacteria are able to evade existing antibiotic treatments faster than researchers can develop new ones. </p>
<p>By reconstructing microbial genomes from archaeological samples, scientists can tap into the hidden diversity of natural products that would have otherwise been lost over time, increasing the number of potential sources from which they can discover new drugs.</p>
<h2>Scaling up ancient molecules</h2>
<p>Our study has shown that it is possible to access natural products from the past. To tap into the vast diversity of chemical compounds encoded in ancient DNA, we now need to streamline our methodology to be less labor-intensive. </p>
<p>We are currently optimizing and automating our process to identify biosynthetic genes in ancient DNA more quickly and reliably. We are also implementing robotic liquid handling systems to complete the time-consuming pipetting and bacterial cultivation steps in our methods. Our goal is to scale up the process to be able to translate a vast amount of data on ancient microbes into the discovery of new therapeutic agents. </p>
<p>Although we can recreate ancient molecules, their biological and ecological roles are difficult to decipher. Since the bacteria that originally produced these compounds no longer exist, we cannot culture or genetically manipulate them. Further study will need to rely on similar bacteria that can be found today. Whether or not the functions of these compounds have remained the same in the modern relatives of ancient microbes remains to be tested. Although the original functions of these compounds for ancient microbes may be unknown, they still have the potential to be repurposed to treat modern diseases.</p>
<p>Ultimately, we aim to shed new light on microbial evolution and fight the current antibiotic crisis by providing a new time axis for antibiotic discovery.</p><img src="https://counter.theconversation.com/content/204888/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Christina Warinner receives funding from the Werner Siemens Foundation, the Francis Goelet Charitable Trust, the European Research Council, the United States National Science Foundation, and the Deutsche Forschungsgemeinschaft. She is affiliated with the Max Planck Institute for Evolutionary Anthropology, the Leibniz Institute of Natural Product Research and Infection Biology (Leibniz-HKI), and the Biological Faculty of Friedrich Schiller University Jena. </span></em></p><p class="fine-print"><em><span>Alexander Hübner receives funding from the Werner Siemens Foundation, the European Research Council, and the Deutsche Forschungsgemeinschaft. He is affiliated with with the Leibniz Institute of Natural Product Research and Infection Biology (Leibniz-HKI).</span></em></p><p class="fine-print"><em><span>Pierre Stallforth receives funding from the Werner Siemens Foundation, the Deutsche Forschungsgemeinschaft, and the Leibniz Association. He is affiliated with with the Leibniz Institute of Natural Product Research and Infection Biology (Leibniz-HKI) and the Friedrich Schiller University, Jena, Germany.</span></em></p>
Ancient microbes likely produced natural products their descendants today do not. Tapping into this lost chemical diversity could offer a potential source of new drugs.
Christina Warinner, Associate Professor of Anthropology, Harvard University
Alexander Hübner, Postdoctoral Researcher in Archaeogenetics, Max Planck Institute for Evolutionary Anthropology
Pierre Stallforth, Professor of Bioorganic Chemistry and Paleobiotechnology, Friedrich-Schiller-Universität Jena
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/204797
2023-05-03T20:17:39Z
2023-05-03T20:17:39Z
Who owned this Stone Age jewellery? New forensic tools offer an unprecedented answer
<figure><img src="https://images.theconversation.com/files/523993/original/file-20230503-16-syi8cw.jpg?ixlib=rb-1.1.0&rect=5%2C0%2C3982%2C3000&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Max Planck Institute for Evolutionary Anthropology</span></span></figcaption></figure><p>An international team of researchers has recovered DNA from the owner of a deer-tooth pendant that was buried inside a remote Siberian cave for tens of thousands of years.</p>
<p>In <a href="https://www.nature.com/articles/s41586-023-06035-2">research published in Nature</a>, Elena Essel of the Max Planck Institute for Evolutionary Anthropology in Germany and colleagues detail how they developed a new technique to extract DNA left behind on an artefact.</p>
<p>In much the same way police solve crimes using “touch DNA” – DNA recovered from skin cells or trace bodily fluids left behind when somebody touches an object – archaeologists will now be able to recover genetic traces of ancient humans from the artefacts they left behind.</p>
<p>These traces will reveal the biological sex and genetic ancestry of the individual who once held or wore a particular artefact, allowing archaeologists to link genetic and cultural evidence as they attempt to unravel the deep past.</p>
<h2>Prehistoric artefacts and touch DNA</h2>
<p>When archaeologists find artefacts such as tools and ornaments at a site, it’s not easy to work out who used them. </p>
<p>Until now, we have had to rely on finding artefacts in “direct association” with buried people. That is, we could only link an individual to an ornament if we found them buried wearing it. </p>
<p>Even then, this funerary association isn’t always a guide to what happened in life. The dead are buried with things their community think they should have, which may not have been theirs when they were alive. </p>
<p>This new method of ancient DNA extraction provides a more direct way of determining who used specific items in everyday life.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/523725/original/file-20230502-1369-p0y4tt.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo of a woman in clean-room gear holding a small bone object inside a perspex box." src="https://images.theconversation.com/files/523725/original/file-20230502-1369-p0y4tt.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523725/original/file-20230502-1369-p0y4tt.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=467&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523725/original/file-20230502-1369-p0y4tt.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=467&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523725/original/file-20230502-1369-p0y4tt.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=467&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523725/original/file-20230502-1369-p0y4tt.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=587&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523725/original/file-20230502-1369-p0y4tt.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=587&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523725/original/file-20230502-1369-p0y4tt.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=587&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Elena Essel working on the pierced deer tooth discovered at Denisova Cave.</span>
<span class="attribution"><span class="source">Max Planck Institute for Evolutionary Anthropology</span></span>
</figcaption>
</figure>
<p>The method can only be used for artefacts made from bone or tooth as these materials are porous and can soak up human DNA from repeated contact with bodily fluids (sweat, blood, saliva). Luckily, the <a href="https://link.springer.com/referenceworkentry/10.1007/978-1-4419-0465-2_702#:%7E:text=%22Bone%20tool%22%20is%20a%20generic,address%20a%20variety%20of%20questions.">bones and teeth of animals</a> (and <a href="https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0182127">sometimes humans</a>) were widely used throughout the past to create everyday tools, sacred items, and personal adornment. </p>
<p>These osseous artefacts were held in the hand or worn against the body for extended periods, resulting in sweat and other fluids soaking into their surfaces over time. As a result, the artefact records the genetic information of the wearer. </p>
<p>Through experimentation with different techniques, Essel and her team found a way to recover that DNA record in a form that is intact enough to be read.</p>
<h2>Is this yours?</h2>
<p>Using this new method of DNA extraction, the researchers were able to extract a wealth of archaeological information from a single tooth pendant recovered from the famous archaeological site of Denisova Cave in Siberia.</p>
<p>The cave, tucked away in the foothills of the Altai mountains, has fascinated researchers for decades as its past inhabitants included not only <em>Homo sapiens</em> but also Neanderthals and another enigmatic extinct human species known as Denisovans.</p>
<figure class="align-center ">
<img alt="A photo of the entrance to a cave in a tree-covered hill." src="https://images.theconversation.com/files/523756/original/file-20230502-26-glp9vv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/523756/original/file-20230502-26-glp9vv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/523756/original/file-20230502-26-glp9vv.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/523756/original/file-20230502-26-glp9vv.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/523756/original/file-20230502-26-glp9vv.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/523756/original/file-20230502-26-glp9vv.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/523756/original/file-20230502-26-glp9vv.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Over the millennia, Denisova Cave has been inhabited by Homo sapiens as well as our extinct cousins the Neanderthals and Denisovans.</span>
<span class="attribution"><span class="source">Richard G. Roberts</span></span>
</figcaption>
</figure>
<p>First, they were able to extract the DNA of the animal the tooth belonged to, a wapiti deer (<em>Cervus canadensis</em>).</p>
<p>They were then able to extract human DNA from the pores of the tooth and deduce that this DNA had come from a female individual whose ancestry is most similar to ancient people found further east in Siberia and with Native Americans.</p>
<p>They were also able to use the DNA data to estimate the date of the pendant’s creation, somewhere between 19,000 and 25,000 years ago. This date fits with previous radiocarbon dating of the layer of the cave floor sediment in which the artefact was found.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/VYec_Ti2H4Q?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">DNA found in soil, or “environmental DNA”, can also inform our understanding of who used an archaeological site such as Denisova Cave.</span></figcaption>
</figure>
<p>Without the extraction and analysis of the human DNA held in the tooth, archaeologists would have been able to tell what animal it had come from and how old it was. However, we could never have guessed the owner of this ornament. Now we can identify a specific individual. </p>
<p>Using the additional DNA information attached to individual artefacts, archaeologists will be able to create an understanding of past societies with a level of detail never before possible.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/dirty-secrets-sediment-dna-reveals-a-300-000-year-timeline-of-ancient-and-modern-humans-living-in-siberia-161585">Dirty secrets: sediment DNA reveals a 300,000-year timeline of ancient and modern humans living in Siberia</a>
</strong>
</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/204797/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michelle Langley is an Associate Professor of Archaeology in the Australian Research Centre for Human Evolution at Griffith University. She receives funding from the ARC. </span></em></p>
A way to recover the owner’s DNA from ancient artefacts will help archaeologists understand past societies in more detail than ever before.
Michelle Langley, Associate Professor of Archaeology, Griffith University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/196555
2023-05-02T12:14:34Z
2023-05-02T12:14:34Z
Enigmatic human fossil jawbone may be evidence of an early ‘Homo sapiens’ presence in Europe – and adds mystery about who those humans were
<figure><img src="https://images.theconversation.com/files/522664/original/file-20230424-25-snjmo4.jpg?ixlib=rb-1.1.0&rect=1041%2C1616%2C9952%2C6772&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Close examination of digital and 3D-printed models suggested the fossil needs to be reclassified.</span> <span class="attribution"><span class="source">Brian A. Keeling</span></span></figcaption></figure><p><em>Homo sapiens</em>, our own species, evolved in Africa sometime between <a href="https://doi.org/10.1038/nature22336">300,000</a> and <a href="https://doi.org/10.1038/s41586-021-04275-8">200,000</a> years ago. Anthropologists are pretty confident in that estimate, based on <a href="https://doi.org/10.1098/rstb.2015.0237">fossil</a>, <a href="https://doi.org/10.1038/325031a0">genetic</a> and <a href="https://doi.org/10.1016/j.quascirev.2008.09.010">archaeological</a> evidence.</p>
<p>Then what happened? How modern humans spread throughout the rest of the world is one of the most active areas of research in human evolutionary studies.</p>
<p>The earliest fossil evidence of our species outside of Africa is found at <a href="https://www.science.org/content/article/ancient-jawbone-suggests-our-species-left-africa-40000-years-earlier-expected">a site called Misliya cave</a>, in the Middle East, and dates to around 185,000 years ago. While additional <em>H. sapiens</em> fossils are found from around 120,000 years ago in this same region, it seems modern humans reached Europe much later.</p>
<p>Understanding when our species migrated out of Africa can reveal insights into present-day biological, behavioral and cultural diversity. While we <em>Homo sapiens</em> are the only humans alive today, <a href="https://doi.org/10.1016/j.quaint.2016.06.008">our species coexisted</a> with different human lineages in the past, including <a href="https://doi.org/10.3998/jar.0521004.0069.202">Neandertals</a> and <a href="https://doi.org/10.17746/1563-0110.2020.48.3.003-032">Denisovans</a>. Scientists are interested in when and where <em>H. sapiens</em> encountered these other kinds of humans.</p>
<p><a href="https://scholar.google.com/citations?user=EjyT0fIAAAAJ&hl=en&oi=ao">Our</a> <a href="https://scholar.google.com/citations?user=JG6YfO4AAAAJ&hl=en&oi=ao">recent</a> reanalysis of a <a href="https://doi.org/10.1016/j.jhevol.2022.103291">fossil jawbone from a Spanish site called Banyoles</a> is raising new questions about when our species may have migrated to Europe.</p>
<h2><em>Homo sapiens</em> fossils found in Europe</h2>
<p>The <a href="https://australian.museum/learn/science/human-evolution/a-timeline-of-fossil-discoveries/">first documented discoveries</a> of human fossils were in Europe, just before Darwin’s 1859 publication of “<a href="https://www.britannica.com/biography/Charles-Darwin/On-the-Origin-of-Species">The Origin of Species</a>.” Ideas of evolution were being actively debated within European universities and scientific societies.</p>
<p>Many of the earliest fossil findings were <a href="https://www.nhm.ac.uk/discover/who-were-the-neanderthals.html">Neandertals</a>, a species that evolved in Europe by 250,000 years ago and became extinct around 40,000 years ago. They <a href="https://humanorigins.si.edu/evidence/genetics/ancient-dna-and-neanderthals">are also our closest evolutionary relatives</a> and, because of ancient interbreeding, the genomes of people today include Neandertal DNA. Because of their early historical presence, Neandertal fossils had a big influence on how early researchers thought about human evolution. </p>
<p>The first <a href="https://doi.org/10.1073/pnas.192464099">fossil evidence of Neandertals was found in 1856</a> during quarrying activities from the Neander Tal (Neander Valley) in Germany. Paleontologists took the hint and started to search for human fossils in other caves and exposed areas that preserved ancient sediments.</p>
<p>More than a decade later, in 1868, paleontologists uncovered <em>H. sapiens</em> fossils at the <a href="https://humanorigins.si.edu/evidence/human-fossils/fossils/cro-magnon-1">site of Cro-Magnon in southern France</a>. For much of the 20th century, the 30,000-year-old Cro-Magnon fossils represented the earliest fossil evidence of our species in Europe.</p>
<p>More recently, evidence for an earlier <em>H. sapiens</em> presence in Europe has come from two sites in Eastern Europe, including a partial skull from <a href="https://doi.org/10.1038/s41559-021-01443-x">Zlatý kůň Cave in Czechia</a> dating to 45,000 years ago, as well as more fragmentary remains from <a href="https://doi.org/10.1038/s41586-020-2259-z">Bacho Kiro Cave in Bulgaria</a> dating to around 44,000 years ago. Ancient DNA analysis has confirmed that the fossils from these sites represent <em>H. sapiens</em>. Additional, potentially earlier, evidence is represented by a <a href="https://theconversation.com/new-research-suggests-modern-humans-lived-in-europe-10-000-years-earlier-than-previously-thought-in-neanderthal-territories-176648">single tooth dating to 54,000 years ago</a> from the <a href="https://doi.org/10.1126/sciadv.abj9496">Grotte Mandrin Cave in France</a>.</p>
<p>This is where the human fossil from Banyoles comes into the story.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/t_ZZkzCbd3U?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A new look at an old fossil find potentially pushes back the date when <em>Homo sapiens</em> lived in Europe.</span></figcaption>
</figure>
<h2>Reinvestigating a ‘Neandertal’ mandible</h2>
<p>Over a century ago in 1889, a fossil human lower jaw, or mandible, was found at a quarry near the town of Banyoles, in northeastern Spain. Pere Alsius, a prominent local pharmacist, first studied the mandible, and the fossil has been curated by his family ever since.</p>
<p>A number of anthropologists have studied the fossil over time, but it has not usually been included in discussions about <em>H. sapiens</em> in Europe. Most researchers instead argued it represented a Neandertal or showed Neandertal-like features, in part because the Banyoles fossil lacks a feature considered typical and diagnostic of our own species: a bony chin on the front of the mandible.</p>
<p>Researchers did not have a good idea of how old the Banyoles mandible was, with most believing it likely dated to the Middle Pleistocene (780,000-130,000 years ago). That age made it seem too old to represent <em>H. sapiens</em>. Thus, with the absence of a chin and the presumed early date, the designation as a Neandertal seemed to make sense.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/502873/original/file-20230103-20-qzh844.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map showing the green and rocky terrain of Spain with fossil discovery sites indicated." src="https://images.theconversation.com/files/502873/original/file-20230103-20-qzh844.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502873/original/file-20230103-20-qzh844.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=429&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502873/original/file-20230103-20-qzh844.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=429&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502873/original/file-20230103-20-qzh844.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=429&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502873/original/file-20230103-20-qzh844.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=539&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502873/original/file-20230103-20-qzh844.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=539&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502873/original/file-20230103-20-qzh844.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=539&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Map of the Iberian Peninsula indicating where the Banyoles mandible (yellow star) was found, along with Late Pleistocene Neandertal (orange triangles) and <em>H. sapiens</em> (white squares) sites.</span>
<span class="attribution"><span class="source">Brian A. Keeling</span></span>
</figcaption>
</figure>
<p>Based on recent modern <a href="https://doi.org/10.1007/978-1-4020-4409-0_50">uranium-series</a> and <a href="https://doi.org/10.1007/978-1-4757-9694-0_8">electron spin resonance</a> dating, researchers now believe the Banyoles mandible is between 45,000 and 66,000 years old. This younger estimate overlaps with the early <em>H. sapiens</em> fossils from Eastern Europe.</p>
<p>Working with Spanish paleoanthropologists and archaeologists, we took another look at what species the fossil might represent. We relied on a CT scan to virtually reconstruct damaged or missing portions of the mandible and generated a 3D model of the complete fossil. Then, we studied its overall shape and distinctive anatomical features, comparing it to <em>H. sapiens</em>, Neandertals and other earlier human species.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/502874/original/file-20230103-26-x4inu6.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Three side-by-side digital reconstructions of the Banyoles mandible, from side and above." src="https://images.theconversation.com/files/502874/original/file-20230103-26-x4inu6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502874/original/file-20230103-26-x4inu6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=200&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502874/original/file-20230103-26-x4inu6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=200&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502874/original/file-20230103-26-x4inu6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=200&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502874/original/file-20230103-26-x4inu6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=251&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502874/original/file-20230103-26-x4inu6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=251&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502874/original/file-20230103-26-x4inu6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=251&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Virtual reconstruction of the 3D model of the Banyoles mandible. Highlighted piece in blue indicates a mirrored element that researchers used to fill out missing sections.</span>
<span class="attribution"><span class="source">Brian A. Keeling</span></span>
</figcaption>
</figure>
<p>In contrast to earlier analyses, our results revealed that the Banyoles jawbone was most similar to <em>H. sapiens</em> fossils – not Neandertals.</p>
<p>When we examined the mandible’s bony features where muscle tendons and ligaments would have attached, it most closely resembled <em>H. sapiens</em>. We also found no unique bony features shared with the Neandertals. Additionally, when we used sophisticated 3D analysis techniques, we found that Banyoles’ overall shape was a better match with <em>H. sapiens</em> than with Neandertal individuals.</p>
<p>While nearly all of our evidence suggests this prehistoric human was indeed a member of our species, the lack of a chin remains puzzling. This feature is present in all human populations today and should be present in Banyoles if it is a member of our species.</p>
<h2>Figuring out the closest match</h2>
<p>How do we reconcile our results showing that Banyoles is a modern human with the fact that it lacks one of the most distinctive modern human features? We considered several possible scenarios.</p>
<p>When the mandible was discovered, it was still encased in a hard travertine block and only partially exposed. During initial cleaning and preparation of the specimen, it was <a href="https://helvia.uco.es/bitstream/handle/10396/16390/carandell51.pdf?sequence=1&isAllowed=y">accidentally dropped</a> and the chin region was damaged. The fossil was subsequently reconstructed, with the damaged fragments aligned in their correct anatomical position, and the current state of the fossil does seem to accurately reflect an original chinless shape. Thus, the lack of a chin in Banyoles cannot be attributed to this initial incident.</p>
<p>Could the lack of a chin in the Banyoles fossil be a result of interbreeding with Neandertals, who also lacked a chin? <a href="https://doi.org/10.1371/journal.pgen.1002947">Genetic evidence</a> suggests that <em>H. sapiens</em> most likely interbred with Neandertals between 45,000 and 65,000 years ago, making this a possibility.</p>
<p>To assess this hypothesis, we compared Banyoles with an early <em>H. sapiens</em> mandible dating to about 42,000 years ago from <a href="https://doi.org/10.1073%2Fpnas.2035108100">a Romanian site called Peştera cu Oase</a>. <a href="https://doi.org/10.1038/nature14558">Ancient DNA analysis</a> has revealed that the Oase individual had a Neandertal ancestor between four and six generations back, making it close to a hybrid individual. However, unlike Banyoles, this mandible shows a full chin along with some other Neandertal features. Since Banyoles shared no distinctive features with Neandertals, we ruled out the possibility of this individual representing interbreeding between Neandertals and <em>H. sapiens</em>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/502875/original/file-20230103-24-rjv92m.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Three different lower jaw bones side by side" src="https://images.theconversation.com/files/502875/original/file-20230103-24-rjv92m.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/502875/original/file-20230103-24-rjv92m.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=226&fit=crop&dpr=1 600w, https://images.theconversation.com/files/502875/original/file-20230103-24-rjv92m.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=226&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/502875/original/file-20230103-24-rjv92m.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=226&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/502875/original/file-20230103-24-rjv92m.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=284&fit=crop&dpr=1 754w, https://images.theconversation.com/files/502875/original/file-20230103-24-rjv92m.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=284&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/502875/original/file-20230103-24-rjv92m.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=284&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Comparison of mandibles between <em>H. sapiens</em>, at left; Banyoles, center; and a Neandertal, at right.</span>
<span class="attribution"><span class="source">Brian A. Keeling</span></span>
</figcaption>
</figure>
<p>We’re left with two possibilities. Banyoles may represent a hybrid individual between <em>H. sapiens</em> and a non-Neandertal archaic human lineage. This scenario might account for the absence of the chin as well as the lack of any other Neandertal features in Banyoles. However, scientists haven’t identified any such non-Neandertal archaic group in the fossil record of the European <a href="https://www.geosociety.org/GSA/Education_Careers/Geologic_Time_Scale/GSA/timescale/home.aspx">Late Pleistocene</a> (129,000-11,700 years ago), making this hypothesis less likely.</p>
<p>Alternatively, Banyoles may document a previously unknown lineage of largely chinless <em>H. sapiens</em> in Europe. Possible support for this hypothesis comes from the fact that early <em>H. sapiens</em> fossils from Africa and the Middle East show a less prominent chin than do living humans. </p>
<p>Additionally, <a href="https://doi.org/10.1038/nature17993">ancient DNA research</a> has shown that <em>H. sapiens</em> populations in Europe before 35,000 years ago did not contribute to the modern European gene pool. Thus, we believe the least unlikely hypothesis is that Banyoles represents an individual from one of these early <em>H. sapiens</em> populations.</p>
<p>Our study of Banyoles demonstrates how new discoveries about our evolutionary past do not solely rely on new fossil discoveries, but can also come about through applying new methodologies to previously discovered fossils. If Banyoles is really a member of our species, it would potentially represent the earliest <em>H. sapiens</em> lineage documented to date in Europe. Future ancient DNA analysis could confirm or refute this surprising result. In the meantime, <a href="https://www.morphosource.org/">the 3D model of Banyoles</a> is available for other researchers to study and form their own conclusions.</p><img src="https://counter.theconversation.com/content/196555/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Scientists had figured a fossil found in Spain more than a century ago was from a Neandertal. But a new analysis suggests it could be from a lost lineage of our species, Homo sapiens.
Brian Anthony Keeling, Doctoral Candidate in Anthropology, Binghamton University, State University of New York
Rolf Quam, Associate Professor of Anthropology, Binghamton University, State University of New York
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/201154
2023-03-29T15:02:28Z
2023-03-29T15:02:28Z
Ancient DNA is restoring the origin story of the Swahili people of the East African coast
<figure><img src="https://images.theconversation.com/files/516781/original/file-20230321-2514-xlebqo.jpg?ixlib=rb-1.1.0&rect=278%2C16%2C2537%2C1926&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">How are people today related to those who lived centuries ago in the Swahili civilization? </span> <span class="attribution"><a class="source" href="https://flic.kr/p/eQ6o77">The Bureau of Educational and Cultural Affairs/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>The legacy of the medieval Swahili civilization is a source of extraordinary pride in East Africa, as reflected in its language being the official tongue of Kenya, Tanzania and even inland countries like Uganda and Rwanda, far from the Indian Ocean shore where the culture developed nearly two millennia ago.</p>
<p>Its ornate stone and coral towns hugged 2,000 miles (3,200 kilometers) of the coast, and its merchants played a linchpin role in the lucrative trade between Africa and lands across the ocean: Arabia, Persia, India, Southeast Asia and China.</p>
<p>By the turn of the second millennium, Swahili people embraced Islam, and some of their grand mosques still stand at the UNESCO World Heritage sites of <a href="https://whc.unesco.org/en/list/1055/">Lamu in Kenya</a> and <a href="https://whc.unesco.org/en/list/144">Kilwa in Tanzania</a>.</p>
<p>Self-governance ended following Portuguese colonization in the 1500s, with control later shifting to the Omanis (1730-1964), Germans in Tanganyika (1884-1918) and British in Kenya and Uganda (1884-1963). Following independence, coastal peoples were absorbed into the modern nation-states of Somalia, Kenya, Tanzania, Mozambique and Madagascar.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/516769/original/file-20230321-2560-1pocur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="old color map of a hilly island with a town on one side" src="https://images.theconversation.com/files/516769/original/file-20230321-2560-1pocur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516769/original/file-20230321-2560-1pocur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=486&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516769/original/file-20230321-2560-1pocur.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=486&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516769/original/file-20230321-2560-1pocur.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=486&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516769/original/file-20230321-2560-1pocur.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=611&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516769/original/file-20230321-2560-1pocur.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=611&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516769/original/file-20230321-2560-1pocur.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=611&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Swahili island settlement of Kilwa, in present-day Tanzania, grew over centuries to be a major coastal city and trading center.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/in-the-11th-century-the-island-of-kilwa-kisiwani-was-sold-news-photo/1354431211">Pictures From History/Universal Images Group via Getty Images</a></span>
</figcaption>
</figure>
<p>So who were the Swahili people, and where did their ancestors originally come from?</p>
<p>Ironically, the story of Swahili origins has been molded almost entirely by non-Swahili people, a challenge shared with many other marginalized and colonized peoples who are the modern descendants of cultures of the past with extraordinary achievements.</p>
<p>Working with a team of 42 colleagues, including 17 African scholars and multiple members of the Swahili community, we’ve now published the <a href="https://doi.org/10.1038/s41586-023-05754-w">first ancient DNA sequences from peoples of the Swahili civilization</a>. Our results do not provide simple validation for the narratives previously advanced in archaeological, historical or political circles. Instead, they contradict and complicate all of them.</p>
<h2>Colonization affected how the story was told</h2>
<p>Western archaeologists in the mid-20th century emphasized the <a href="https://www.worldcat.org/title/1174314">connections of the medieval Swahili to Persia and Arabia</a>, sometimes suggesting that <a href="https://www.worldcat.org/title/1672964">their impressive achievements</a> could not have been <a href="https://www.publicmedievalist.com/recovering-medieval-africa/">attained by Africans</a>.</p>
<p>Post-colonial scholars, including one of us (<a href="https://scholar.google.com/citations?user=5NehBh4AAAAJ&hl=en&oi=ao">Kusimba</a>), pushed back against that view. Earlier researchers had inflated the importance of non-African influences by focusing on imported objects at Swahili sites. They minimized the vast majority of locally made materials and what they <a href="https://www.worldcat.org/title/905641508?oclcNum=905641508">revealed about African industry and innovation</a>.</p>
<p>But viewing Swahili heritage as primarily African or non-African is too simplistic. In fact, both perspectives are byproducts of colonialist biases.</p>
<p>The truth is that colonization of the East African coast did not end with the departure of the British in the middle of the 20th century. Many colonial institutions were <a href="https://www.google.com/books/edition/Plundering_Africa_s_Past/qCBxNhZxSPMC?hl=en&gbpv=1&dq=Destruction+of+Swahili+Heritage&pg=PA201&printsec=frontcover">inherited and perpetuated by Africans</a>. As modern nation-states formed, with governments controlled by inland peoples, <a href="https://africaworldpressbooks.com/the-swahili-idiom-and-identity-of-an-african-people-by-alamin-m-mazuri-and-ibrahim-noor-shariff/">Swahili people continued</a> <a href="https://iupress.org/9780253210548/plundering-africas-past/">to be undermined</a> politically and economically, in some cases as much as they had been under foreign rule.</p>
<p>Decades of archaeological research in consultation with local people aimed to address the marginalization of communities of Swahili descent. Our team consulted oral traditions and used ethnoarchaeology and systematic surveys, along with targeted excavations of residential, industrial and cemetery locations. Working with local scholars and elders, we unearthed materials such as pottery, metal and beads; food, house and industrial remains; and imported objects such as porcelain, glass, glass beads and more. Together they revealed the complexity of Swahili everyday life and the peoples’ cosmopolitan Indian Ocean heritage.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/516767/original/file-20230321-3114-lin1g3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="woodsy setting with a stone wall enclosing an area with grave stones" src="https://images.theconversation.com/files/516767/original/file-20230321-3114-lin1g3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516767/original/file-20230321-3114-lin1g3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516767/original/file-20230321-3114-lin1g3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516767/original/file-20230321-3114-lin1g3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516767/original/file-20230321-3114-lin1g3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516767/original/file-20230321-3114-lin1g3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516767/original/file-20230321-3114-lin1g3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">For generations, Swahilis have maintained matrilineal family burial gardens such as this one in Faza town, Lamu County.</span>
<span class="attribution"><span class="source">Chapurukha Kusimba, 2012</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Ancient DNA analysis was always one of the most exciting prospects. It offered the hope of using scientific methods to obtain answers to the question of how medieval people are related to earlier groups and to people today, providing a counterweight to narratives imposed from outside. Until a few years ago, this kind of analysis was a dream. But because of a <a href="https://reich.hms.harvard.edu/why-i-wrote-book">technological revolution in 2010</a>, the number of ancient humans with published genome-scale data has risen from nothing to <a href="https://reich.hms.harvard.edu/allen-ancient-dna-resource-aadr-downloadable-genotypes-present-day-and-ancient-dna-data">more than 10,000 today</a>.</p>
<h2>Surprises in the ancient DNA</h2>
<p>We worked with local communities to determine the best practices for treating human remains in line with traditional Muslim religious sensitivities. Cemetery excavations, sampling and reburial of human remains were carried out in one season, rather than dragging on indefinitely.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/516773/original/file-20230321-2318-sfwzc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="black and white drawing of a skeleton on its side" src="https://images.theconversation.com/files/516773/original/file-20230321-2318-sfwzc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/516773/original/file-20230321-2318-sfwzc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=236&fit=crop&dpr=1 600w, https://images.theconversation.com/files/516773/original/file-20230321-2318-sfwzc9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=236&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/516773/original/file-20230321-2318-sfwzc9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=236&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/516773/original/file-20230321-2318-sfwzc9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=297&fit=crop&dpr=1 754w, https://images.theconversation.com/files/516773/original/file-20230321-2318-sfwzc9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=297&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/516773/original/file-20230321-2318-sfwzc9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=297&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A detailed line drawing captures the way one person’s remains were discovered during cemetery excavation at Mtwapa in 1996.</span>
<span class="attribution"><span class="source">Eric Wert, 2001</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Our team generated data from more than 80 people, mostly elite individuals buried in the rich centers of the stone towns. We will need to wait for future work to understand whether their genetic inheritance differed from people without their high status. </p>
<p>Contradicting what we had expected, the ancestry of the people we analyzed was not largely African or Asian. Instead, these backgrounds were intertwined, each contributing about half of the DNA of the people we analyzed.</p>
<p>We found that Asian ancestry in the medieval individuals came largely from Persia (modern-day Iran), and that Asians and African ancestors began mixing at least 1,000 years ago. This picture is almost a perfect match to the <a href="https://www.thoughtco.com/kilwa-chronicle-sultan-list-swahili-culture-171631">Kilwa Chronicle</a>, the oldest narrative told by the Swahili people themselves, and one almost all <a href="https://doi.org/10.2307/3171745">earlier scholars had dismissed</a> as a kind of fairy tale.</p>
<p>Another surprise was that, mixed in with the Persians, Indians were a significant proportion of the earliest migrants. Patterns in the DNA also suggest that, after the transition to Omani control in the 18th century, Asian immigrants became increasingly Arabian. Later, there was intermarriage with people whose DNA was similar to others in Africa. As a result, some modern people who identify as Swahili have inherited relatively little DNA from medieval peoples like those we analyzed, while others have more.</p>
<p>One of the most revealing patterns our genetic analysis identified was that the overwhelming majority of male-line ancestors came from Asia, while female-line ancestors came from Africa. This finding must reflect a history of Persian males traveling to the coast and having children with local women.</p>
<p>One of us (<a href="https://reich.hms.harvard.edu">Reich</a>) initially hypothesized that these patterns might reflect Asian men forcibly marrying African women because similar genetic signatures in other populations are known to <a href="https://nautil.us/social-inequality-leaves-a-genetic-mark-237027/">reflect such violent histories</a>. But this theory does not account for what is known about the culture, and there is a more likely explanation.</p>
<p>Traditional Swahili society is similar to many other East African Bantu cultures <a href="https://www.jstor.org/stable/45341518">in being substantially matriarchal</a> – it places much economic and social power in the hands of women. In traditional Swahili societies even today, ownership of stone houses <a href="http://www.siupress.com/books/978-0-8093-3397-4">often passes down the female line</a>. And there is a long recorded history of female rulers, beginning with Mwana Mkisi, ruler of Mombasa, as recorded by the Portuguese as early as the 1500s, down to Sabani binti Ngumi, ruler of Mikindani in Tanzania as late as 1886.</p>
<p>Our best guess is that Persian men allied with and married into elite families and adopted local customs to enable them to be more successful traders. The fact that their children passed down the language of their mothers, and that encounters with traditionally patriarchal Persians and Arabians and conversion to Islam did not change the coast’s African matriarchal traditions, confirms that this was not a simple history of African women being exploited. African women retained critical aspects of their culture and passed it down for many generations.</p>
<p>How do these results gleaned from ancient DNA restore heritage for the Swahili? Objective knowledge about the past has great potential to help marginalized peoples. By making it possible to challenge and overturn narratives imposed from the outside for political or economic ends, scientific research provides a meaningful and underappreciated tool for righting colonial wrongs.</p>
<p><em>Editor’s note: We removed an archival photo that was not representative of Swahili dress.</em></p><img src="https://counter.theconversation.com/content/201154/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Chapurukha M. Kusimba received funding for this research from the Field Museum of Natural History, the National Science Foundation, the U.S. National Endowment for the Humanities, the Fulbright Scholars Program, and the National Geographic Society.</span></em></p><p class="fine-print"><em><span>David Reich received funding from the Howard Hughes Medical Institute, the National Institutes of Health, the John Templeton Foundation and the Allen Discovery Center program, a Paul G. Allen Frontiers Group advised program of the Paul G. Allen Family Foundation.</span></em></p>
The first ancient DNA sequences from peoples of the medieval Swahili civilization push aside colonialist stories and reveal genetic connections from the past.
Chapurukha Kusimba, Professor of Anthropology, University of South Florida
David Reich, Professor of Genetics and of Human Evolutionary Biology, Harvard University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/197221
2023-01-05T20:33:11Z
2023-01-05T20:33:11Z
DNA reveals large migration into Scandinavia during the Viking age
<figure><img src="https://images.theconversation.com/files/503216/original/file-20230105-20-c8gnzd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">More people moved into Scandinavia in Viking times than at any other time period analysed in the study.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/old-wooden-viking-snekkja-longship-type-2044280747">Shutterstock</a></span></figcaption></figure><p>We often think of the Vikings as ultimate explorers, taking their culture with them to far-off lands. But we may not typically think of Viking age Scandinavia as a hub for migration from all over Europe.</p>
<p><a href="https://www.cell.com/cell/fulltext/S0092-8674(22)01468-4">In a study published in Cell</a>, we show this is exactly what happened. The Viking period (late 8th century to mid 11th century) was the catalyst for an exceptional inflow of people into Scandinavia. These movements were greater than for any other period we analysed.</p>
<p>What’s also striking is that later Scandinavians don’t show the same high levels of non-local ancestry present in their Viking-era counterparts. We don’t completely understand why the migrants’ genetic impact was reduced in later Scandinavians, but there are some possibilities.</p>
<p>We analysed genomes (the full complement of DNA contained in human cells) from around 17,000 Scandinavian individuals, including nearly 300 from ancient burials. We combined <a href="https://www.sciencedirect.com/science/article/pii/S0960982218308443">existing datasets</a> with new samples. These were analysed together in a dataset spanning 2,000 years.</p>
<p>We used these genomes to explore when people arrived in the region from outside and where they came from. New DNA samples were collected from several iconic Swedish archaeological sites. </p>
<p>These included Sandby borg, which is a “ring fortress” <a href="https://www.cambridge.org/core/journals/antiquity/article/moment-frozen-in-time-evidence-of-a-late-fifthcentury-massacre-at-sandby-borg/5C803B7E77A41439BC3B50D4BF96560E">where a massacre occurred just before 500 AD</a>, and the Vendel cemetery, which features several burials contained in large boats and dating to between the 6th and 8th centuries AD. We also used samples from Viking chamber burials and remains from Kronan, a <a href="https://www.tandfonline.com/doi/abs/10.1111/j.1095-9270.1990.tb00276.x">warship that capsized with more than 800 men</a> in 1676.</p>
<p>Two previous studies <a href="https://www.sciencedirect.com/science/article/pii/S0960982218308443">noted extensive migration</a> into Scandinavia <a href="https://www.nature.com/articles/s41586-020-2688-8">during the Viking age</a>. But in our latest study, we have clarified some of the details about this flow of genes into the region.</p>
<p>We found that movements of people from western Europe impacted all of Scandinavia, while migration from the east was more localised, with peaks in the Lake Mälaren Valley and Gotland. Finally, gene flow from southern Europe largely affected the south of Scandinavia. </p>
<p>Since the study was based on a 2,000-year chronology, it was not only possible to see there was an increase in migration during the Viking era, but also that it starts to fall with the onset of the medieval period.</p>
<p>The non-local ancestry that arrives in the region at this time falls away in later periods. Much of the genetic influence from eastern Europe disappears and the western and southern influence becomes significantly diluted. The best way to explain this is that people who arrived in Scandinavia during Viking times did not have as many children as the people who were already living there.</p>
<p>There are different possible reasons for this. The migrants could have belonged to groups that did not intend to settle down in Scandinavia, instead aiming to return to where they came from. Tradespeople and diplomats are examples in this category. Additionally, the migrants could also have belonged to groups that were not allowed to have families or children, such as slaves and priests.</p>
<p>We also looked at influences that began at earlier periods in time. For example, the DNA of modern Scandinavians <a href="https://www.nature.com/articles/s41431-021-00899-6">changes gradually as you travel from north to south</a>. This genetic “cline”, or gradient, is due to migrations into the region of people carrying shared genetic similarities known as the Uralic component.</p>
<p>Modern examples of where the Uralic genetic component can be found are among Sami people, people in modern Finland, some Native Americans and some central Asian groups. </p>
<p>In our dataset, we found occasional instances of people with Uralic ancestry – mainly in northern Scandinavia – during the Viking period and medieval times. But the Uralic influence seems to increase after this time, since individuals from our 17th century sample have similar levels of this ancestry to people living today.</p>
<p>There were many other fascinating stories from our study. For example, at the Viking age burial site of Sala, by the river Sagån, we find a woman that seems to be fully British or Irish in her genomic composition. This woman was buried in a prestigious Viking period boat burial. We don’t know exactly what position she held in society, but she would not have been a slave or a priest. </p>
<p>Among the individuals found on the wreck of the Kronan, there were two people who came from what is now Finland and another who has a genetic affinity with people from the Baltic states, such as Lithuania and Latvia (though this identification is not conclusive). At the time of the Kronan incident in 1676, these areas were part of the Swedish Empire, though they are independent today.</p>
<p>The work sheds more light on the historical events that shaped the populations of Scandinavia over time. The Viking age was marked by Scandinavians’ curiosity of the world outside their home region. But, from our results, it also appears that the world outside this region was curious enough about the Vikings to travel to Scandinavia.</p><img src="https://counter.theconversation.com/content/197221/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Anders Götherström receives funding from VR, KVA, and EU. </span></em></p><p class="fine-print"><em><span>Ricardo Rodriguez Varela does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
DNA analysis reveals a large migration of people into Scandinavia during Viking times.
Anders Götherström, Professor in Molecular Archaeology, Department of Archaeology and Classical Studies, Stockholm University
Ricardo Rodriguez Varela, Research in Molecular Archaeology, Department of Archaeology and Classical Studies, Stockholm University, Stockholm University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/196113
2022-12-08T19:24:21Z
2022-12-08T19:24:21Z
DNA from elusive human relatives the Denisovans has left a curious mark on modern people in New Guinea
<figure><img src="https://images.theconversation.com/files/499706/original/file-20221208-16-p3m533.jpg?ixlib=rb-1.1.0&rect=301%2C139%2C3309%2C2283&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Derek R. Audette/Shutterstock</span></span></figcaption></figure><p>An encounter with a mysterious and extinct human relative – the Denisovans – has left a mark on the immune traits of modern Papuans, in particular those living on New Guinea Island.</p>
<p>This is a new discovery we describe <a href="https://doi.org/10.1371/journal.pgen.1010470">in a study published in PLoS Genetics</a> today. It further suggests that our modern human diversity didn’t just evolve – some parts of it we got from other, extinct human groups.</p>
<h2>DNA from our evolutionary cousins</h2>
<p>Humans are the only living species of the <em>Homo</em> genus. But until 50,000 years ago, our ancestors coexisted – and sometimes interacted – with multiple other <em>Homo</em> groups across the globe. Most of them we know only by <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/jqs.3137">sparse archaeological remains</a>, which offer tantalising glimpses of our evolutionary cousins.</p>
<p>But for two groups there is something else: DNA. Thanks to technological advances, scientists have retrieved DNA from fossils and sequenced it. As a result, we now have complete genome sequences of the best-known archaic hominins, the <a href="http://www.sciencemag.org/cgi/doi/10.1126/science.1188021">Neanderthals</a>, and a far more elusive group, <a href="http://www.nature.com/articles/nature09710">Denisovans</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fresh-clues-to-the-life-and-times-of-the-denisovans-a-little-known-ancient-group-of-humans-110504">Fresh clues to the life and times of the Denisovans, a little-known ancient group of humans</a>
</strong>
</em>
</p>
<hr>
<p>Although many Neanderthal fossils have been unearthed all over Europe since they were first identified in the 1860s, the number of known Denisovan fossils fits in the palm of a hand – literally! </p>
<p>The genome sequence we have comes from the smallest bone of a pinky finger. It belonged to the 60,000-year-old remains of a teenage girl from a cave in Siberia, the largest known Denisovan fossil until recently. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/499709/original/file-20221208-16-4pofku.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="The outline of a skeleton finger on a dark surface with a small, orange bone sitting atop one knuckle" src="https://images.theconversation.com/files/499709/original/file-20221208-16-4pofku.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499709/original/file-20221208-16-4pofku.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499709/original/file-20221208-16-4pofku.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499709/original/file-20221208-16-4pofku.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499709/original/file-20221208-16-4pofku.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499709/original/file-20221208-16-4pofku.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499709/original/file-20221208-16-4pofku.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A museum replica of the Denisovan finger bone used to extract ancient DNA.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Denisova_Phalanx_distalis.jpg">Thilo Parg/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<h2>Traces of ancestors</h2>
<p>These genome sequences have transformed the way we think about our extinct relatives. For one, they quickly demonstrated that as humans expanded outside Africa, we had sex – and children – with these other populations.</p>
<p>Traces of their genomes linger in individuals alive today, transmitted across hundreds of generations.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/evolutionary-study-suggests-prehistoric-human-fossils-hiding-in-plain-sight-in-southeast-asia-157587">Evolutionary study suggests prehistoric human fossils 'hiding in plain sight' in Southeast Asia</a>
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<hr>
<p>In the case of Neanderthals, these traces are in all individuals of non-African ancestry today. In the case of Denisovans, we find small traces of their genome in people from all over Asia – especially in Papua New Guinea, and in the island nations of Southeast Asia, where individuals may owe up to 4–5% of their genome to these ancestors. </p>
<p>But identifying these fragments of DNA in our genomes is only the beginning. </p>
<h2>The DNA makes a difference</h2>
<p>The real challenge is to find the biological consequences of this DNA for the people who carry it – which, it bears remembering, is the vast majority of humans. Our specific research question was to pinpoint the molecular processes that might be affected by its presence.</p>
<p>Studies of Neanderthal DNA have shown that genetic variants inherited from them <a href="https://doi.org/10.1093/molbev/msab304">can alter the levels</a> at which some human genes are expressed, for example. We also know Neanderthals have contributed to <a href="https://linkinghub.elsevier.com/retrieve/pii/S0002929715004863">our immune systems</a> (including differences in how people respond to infection with COVID-19), and to <a href="https://www.nature.com/articles/s41467-021-24582-y">variation in skin and hair colour</a>. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/what-teeth-can-tell-about-the-lives-and-environments-of-ancient-humans-and-neanderthals-104923">What teeth can tell about the lives and environments of ancient humans and Neanderthals</a>
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</em>
</p>
<hr>
<p>But it has never been clear whether Denisovan DNA has left similar trends in modern humans. </p>
<p>In 2019, <a href="https://www.cell.com/cell/abstract/S0092-8674(19)30218-1">a study revealed</a> the genomic coordinates where Denisovan DNA might be found within the genome of Papuan individuals – that is, the indigenous people of New Guinea Island – alive today.</p>
<p>This led us to begin looking into these regions, to understand the cellular and biological processes that might be affected by Denisovan DNA. We took a hybrid approach to this question, making computational predictions first, and following up with laboratory-based experiments to validate our findings.</p>
<p>In addition, we took advantage of the known Neanderthal DNA within these people to highlight any Denisovan-specific contribution. This gave us a more integrated understanding of how encounters with these relatives left potential biological and evolutionary consequences in modern humans.</p>
<h2>A unique Denisovan contribution</h2>
<p>We noticed that in Papuans, Denisovan and Neanderthal genetic variants both occasionally occur within parts of the genome responsible for modulating the expression levels of nearby genes.</p>
<p>However, only Denisovan variants are consistently predicted to occur and affect elements controlling the expression levels of immune-related genes.</p>
<p>So, these different sources of DNA might contribute to the genetic and phenotypic diversity within Papuans in different ways.</p>
<p>To validate our predictions, we designed an experiment comparing five Denisovan sequences against their modern human counterpart, and tested their ability to actually affect gene expression levels inside a particular kind of immune cell known as a lymphocyte.</p>
<p>In two of the five cases, the Denisovan variants did have a measurably different impact on the gene expression levels than their modern human counterpart. And they impact genes known to be important players in the response to infectious microbes, including viruses. </p>
<p>The fact that Denisovans, but not Neanderthals, seem to have contributed to the immune systems of present-day Papuans, tells us something about these ancient people, too.</p>
<p>Although little is known about how widely through Asia Denisovans lived, it suggests their immune system changed to adapt to the infectious diseases of their environment.</p>
<p>When humans moved in <a href="https://science.sciencemag.org/content/361/6397/88">60,000 years ago</a>, these bits of DNA likely contributed to our success in settling this part of the world.</p>
<p>While our study is the first to elucidate the contribution of Denisovan DNA within modern human genetic diversity, there are still exciting questions to address. In particular, it is not clear whether the overall contributions of Denisovan and Neanderthal genetic variants consistently differ from each other.</p>
<p>It is also important to note we tested genetic variants in immune cells under resting conditions. This means the same or other genetic variants might have different effects out in the environment – this will be an important question for studies in the future.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/first-ever-genetic-analysis-of-a-neanderthal-family-paints-a-fascinating-picture-of-a-close-knit-community-192595">First-ever genetic analysis of a Neanderthal family paints a fascinating picture of a close-knit community</a>
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</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/196113/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Irene Gallego Romero receives funding from the Australian Research Council, the Leakey Foundation, the Chan-Zuckerberg Initiative, the Royal Society of New Zealand and the French National Research Agency</span></em></p><p class="fine-print"><em><span>Davide Vespasiani does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Humanity carries traces of other populations in our DNA – and a new study shows how one of these ancestors has influenced the immune systems of modern Papuans.
Irene Gallego Romero, Senior Lecturer in Human Genetics, The University of Melbourne
Davide Vespasiani, Post-doctoral researcher, The University of Melbourne
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/196044
2022-12-07T19:05:36Z
2022-12-07T19:05:36Z
The oldest DNA ever found reveals a snapshot of a vanished world
<figure><img src="https://images.theconversation.com/files/499392/original/file-20221207-16-7qtkic.jpeg?ixlib=rb-1.1.0&rect=57%2C9%2C6366%2C3945&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Beth Zaiken</span></span></figcaption></figure><p>At the icy northern tip of Greenland, far into the Artic Circle, a deep bed of sediment beneath the mouth of a fjord has lain frozen and undisturbed for 2 million years.</p>
<p>Known as the Kap København Formation, this relic of a vanished world dates to a period when Earth was much warmer than it is today. The sediment built up in a shallow bay over a period of 20,000 years, before being buried beneath ice and permafrost.</p>
<p>Our team, led by Kurt Kjær, Mikkel Winter Pedersen and Eske Willerslev at Copenhagen University, has extracted and analysed the oldest DNA ever recovered from samples of this Greenlandic sediment. It reveals the plants, animals and microorganisms that thrived in an ecosystem unlike anything in the modern world.</p>
<p>As we <a href="https://www.nature.com/articles/s41586-022-05453-y">report today in Nature</a>, this DNA is more than a million years older than the previous record. We can now recover and directly study molecules that were made inside plants and animals 2 million years ago, opening a new window into the history of life on Earth.</p>
<h2>A snapshot of an extinct ecosystem</h2>
<p>Two million years ago, northern Greenland was a very different place. Average winter temperatures were more than 10°C warmer, and there was less carbon dioxide in Earth’s atmosphere. </p>
<p>Our study, carried out by more than 40 scientists from Denmark, the UK, France, Sweden, Norway, the USA and Germany, pieced together minuscule fragments of DNA and matched them to sequences of known species. We found genetic traces of ancestors of modern reindeer, hares and lemmings, as well as mastodon – extinct elephant-like creatures which were not previously known to have lived in Greenland. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/499415/original/file-20221207-14-gnsmah.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photograph showing layers of sediment." src="https://images.theconversation.com/files/499415/original/file-20221207-14-gnsmah.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499415/original/file-20221207-14-gnsmah.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499415/original/file-20221207-14-gnsmah.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499415/original/file-20221207-14-gnsmah.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499415/original/file-20221207-14-gnsmah.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499415/original/file-20221207-14-gnsmah.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499415/original/file-20221207-14-gnsmah.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Layers of sediment retain traces of the rich flora and fauna that lived 2 million years ago in Kap København in North Greenland.</span>
<span class="attribution"><span class="source">Kurt H. Kjær</span></span>
</figcaption>
</figure>
<p>We also found DNA traces of plants including birch and poplar trees, as well as algae and other microorganisms – and a large proportion of DNA fragments we could not match to any known species.</p>
<p>But it is not just the specific species that are of interest but also how they co-existed in the same prehistoric ecosystem that was much warmer than today. This can tell us a lot about the possible impact on the biodiversity during warming periods and how it may drive their evolutionary response.</p>
<p>In essence, our study is similar to the “environmental DNA” (eDNA) research ecologists do today to understand biodiversity in modern ecosystems. The difference is that we are looking at an ecosystem that disappeared millions of years ago, which is why the recovery and bioinformatic analysis of these short, degraded molecules becomes a lot more challenging.</p>
<h2>Watching evolution</h2>
<p>We know that the DNA inside cells of all living organisms mutates slowly, as environmental changes drive adaptation and evolution over many generations. However, we very rarely have a “time machine” to go back and look directly at the old DNA molecules.</p>
<p>To understand how DNA has changed over time, we usually compare the genomes of modern species and work backwards to create an evolutionary family tree. However, the possibility of studying DNA that is millions of years old means we will be able to directly observe the deep-time process of molecular evolution, instead of being restricted to the current genetic “snapshot” in present-day species.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-grow-an-evolutionary-tree-65722">How to grow an evolutionary tree</a>
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<hr>
<p>What’s more, the DNA of the ancestors of modern species may show how they adapted to conditions that are very different from the ones they face today. We don’t gain those insights in this study, but if we can study those prehistoric genetic adaptations in detail in the future, it may allow us to predict if species are able to adapt to changes such as the ongoing global warming.</p>
<h2>How long can DNA survive?</h2>
<p>Despite what the Jurassic Park movies may tell you, DNA doesn’t last forever. It decays steadily over time – though the rate of decay depends on circumstances like temperature.</p>
<p>About a decade ago, my colleagues and I published <a href="https://royalsocietypublishing.org/doi/10.1098/rspb.2012.1745">a study of moa fossils</a> that calculated a “half-life” for long-term DNA decay in bones. We predicted that recognisable fragments of DNA should be able to last more than one million years under ideal conditions, such as the deep freeze of permafrost.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/moa-bones-reveal-dna-half-life-but-jurassic-park-remains-fiction-10067">Moa bones reveal DNA half-life but Jurassic Park remains fiction</a>
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<p>And, indeed, in 2021 researchers <a href="https://www.nature.com/articles/s41586-021-03224-9">recovered DNA</a> from the tooth of a mammoth that lived in Siberia approximately 1.2 million years ago. </p>
<p>However, the new research shows something quite surprising. It seems that DNA can actually survive much longer as free molecules in sediment than in the bones of the animal it originally belonged to. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/499418/original/file-20221207-4529-7qtkic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A photo showing old fragments of wood on dusty ground next to a shovel." src="https://images.theconversation.com/files/499418/original/file-20221207-4529-7qtkic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/499418/original/file-20221207-4529-7qtkic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/499418/original/file-20221207-4529-7qtkic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/499418/original/file-20221207-4529-7qtkic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/499418/original/file-20221207-4529-7qtkic.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/499418/original/file-20221207-4529-7qtkic.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/499418/original/file-20221207-4529-7qtkic.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Remains of wooden branches from the forest that grew at Kap København 2 million years ago.</span>
<span class="attribution"><span class="source">Svend Funder</span></span>
</figcaption>
</figure>
<p>DNA molecules can bind to the surface of particles of clay which somehow protect them from the ravages of time. We do not know exactly how long DNA can survive in sediment, but if the preservation conditions are ideal, there is no reason to believe that we have found the limit here at two million years.</p>
<p>Once we know more about what kinds of sediment preserve DNA best, we will be able to hunt for it all over the world – though we are unlikely ever to realise the dream of examing 65 million year–old sequences of dinosaur DNA. I would be very happy to be proven wrong though!</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/whats-next-for-ancient-dna-studies-after-nobel-prize-honors-groundbreaking-field-of-paleogenomics-191899">What’s next for ancient DNA studies after Nobel Prize honors groundbreaking field of paleogenomics</a>
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</em>
</p>
<hr>
<img src="https://counter.theconversation.com/content/196044/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Morten Allentoft does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
DNA frozen for 2 million years paints a picture of an extinct ecosystem.
Morten Allentoft, Professor, Molecular and Life Sciences, Curtin University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/194780
2022-11-30T16:01:54Z
2022-11-30T16:01:54Z
Ancient DNA from the teeth of 14th-century Ashkenazi Jews in Germany already included genetic variations common in modern Jews
<figure><img src="https://images.theconversation.com/files/498055/original/file-20221129-11920-w79ymf.jpg?ixlib=rb-1.1.0&rect=38%2C31%2C2036%2C1406&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Partial layout of the graves discovered during the excavation at the medieval Jewish cemetery of Erfurt.</span> <span class="attribution"><span class="source">Thuringian State Office for Heritage Management and Archaeology/Karin Sczech + Katharina Bielefeld</span></span></figcaption></figure><p>About two-thirds of Jews today – or about 10 million people – are <a href="https://en.wikipedia.org/wiki/Ashkenazi_Jews">Ashkenazi</a>, referring to a recent origin from Eastern and Central Europe. They reside mostly in the United States and Israel. Ashkenazi Jews carry a particularly high burden of <a href="https://www.jewishgeneticdiseases.org/jewish-genetic-diseases/">disease-causing genetic mutations</a>, such as those in the <a href="https://www.cdc.gov/cancer/breast/young_women/bringyourbrave/hereditary_breast_cancer/jewish_women_brca.htm">BRCA1</a> gene associated with an increased risk of breast and ovarian cancer.</p>
<p>This genetic burden suggests that the population was shaped by what geneticists call a <a href="https://evolution.berkeley.edu/bottlenecks-and-founder-effects/">founder event or a bottleneck</a>. In other words, a small number of foremothers and forefathers contributed much of the modern gene pool. As the population grew and the descendants of these founders had many children, disease mutations that were carried by the few founders became widespread.</p>
<p>One of the most striking features of Ashkenazi Jews today is <a href="https://doi.org/10.1093/molbev/msr133">how genetically homogeneous</a> they are, with almost no discernable differences in ancestry between Ashkenazi Jews across the world. Were Ashkenazi Jews equally similar to each other in the past? What were their origins? To what extent was the gene pool shaped by intermarriage with non-Jews?</p>
<p><a href="https://doi.org/10.1146/annurev-genom-083117-021749">New technology</a> has made it practical to economically sequence whole genomes from skeletal remains. <a href="https://scarmilab.org">We</a> <a href="https://reich.hms.harvard.edu">and</a> 30 colleagues mostly from Israel, Germany and the U.S. investigated these questions by <a href="http://dx.doi.org/10.1016/j.cell.2022.11.002">sequencing the centuries-old remains of Ashkenazi Jews</a> from the medieval Jewish community of Erfurt, Germany.</p>
<h2>Sequencing DNA from a medieval cemetery</h2>
<p>Previous studies of genomes of Ashkenazi Jews living today made it clear that the <a href="https://doi.org/10.1016/j.ajhg.2012.08.030">founder event occurred in medieval times</a>. But the earlier geographic origins of the Ashkenazi ancestors are poorly understood.</p>
<p>The first historical records of Ashkenazi Jews are from the Rhineland in Western Germany in the 10th century. In the hundreds of years that followed, an increasing proportion lived in Eastern Europe. Despite periodic persecution, the <a href="https://www.bjpa.org/content/upload/bjpa/dell/DellaPergola%20Some%20Fundamentals.pdf">number of Ashkenazi Jews grew</a> and peaked at more than 10 million in the mid-20th century, before about <a href="https://www.worldcat.org/title/33397139">six million Jews were murdered in the Holocaust</a>.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/498052/original/file-20221129-22-c2soy0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="four story medieval building with excavated dirt in foreground" src="https://images.theconversation.com/files/498052/original/file-20221129-22-c2soy0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/498052/original/file-20221129-22-c2soy0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=901&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498052/original/file-20221129-22-c2soy0.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=901&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498052/original/file-20221129-22-c2soy0.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=901&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498052/original/file-20221129-22-c2soy0.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1132&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498052/original/file-20221129-22-c2soy0.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1132&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498052/original/file-20221129-22-c2soy0.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1132&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Archaeologists worked to recover medieval remains from a graveyard. The granary building is in the background.</span>
<span class="attribution"><span class="source">Thuringian State Office for Heritage Management and Archaeology/Martin Sowa</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>The <a href="https://juedisches-leben.erfurt.de/jl/en/middle-ages/index.html">medieval Ashkenazi Jewish community of Erfurt, Germany</a> existed between the late 11th century and the mid-15th century. After a gap following a 1349 massacre, the Erfurt Jewish community became one of the largest in Germany – in fact, one of the <a href="https://juedisches-leben.erfurt.de/jl/en/middle-ages/old_synagogue/index.html">oldest intact Jewish synagogues</a> in Central Europe is in Erfurt – but Jews were expelled in 1454. After that, the city built a granary on top of the Jewish cemetery.</p>
<p>In 2013, the granary was converted into a parking garage. Prior to construction, the state led a rescue excavation that uncovered 47 graves, most of which we sampled for DNA before the skeletons were reburied in the 19th-century Jewish cemetery.</p>
<p>Our study required review from the local Jewish community, because traditional Jewish law prohibits disturbing the dead under most circumstances. But <a href="https://din.org.il/2021/09/11/%d7%93%d7%92%d7%99%d7%9e%d7%95%d7%aa-%d7%93%d7%a0%d7%90-%d7%9e%d7%a9%d7%9c%d7%93%d7%99%d7%9d-%d7%a2%d7%aa%d7%99%d7%a7%d7%99%d7%9d-%d7%a1%d7%95%d7%92%d7%99%d7%95%d7%aa-%d7%94%d7%9c%d7%9b/">recent rabbinical scholarship</a> suggested that ancient DNA research is permissible if scientists use loose teeth from already excavated remains. We followed this approach with the aim of being <a href="https://doi.org/10.1038/s41586-021-04008-x">sensitive to community perspectives</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/497959/original/file-20221129-12-puyzlr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="tooth next to ruler and labelled plastic bag" src="https://images.theconversation.com/files/497959/original/file-20221129-12-puyzlr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/497959/original/file-20221129-12-puyzlr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=468&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497959/original/file-20221129-12-puyzlr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=468&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497959/original/file-20221129-12-puyzlr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=468&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497959/original/file-20221129-12-puyzlr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=589&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497959/original/file-20221129-12-puyzlr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=589&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497959/original/file-20221129-12-puyzlr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=589&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In accordance with rabbinical ruling, researchers collected DNA from teeth that were already loose in the remains of people who lived during the 1300s.</span>
<span class="attribution"><span class="source">David Reich/Harvard Medical School</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Today’s population is a blend of past groups</h2>
<p>We sequenced 33 individuals who lived in the 14th century. Among them were two families: a mother and two children, and a father, who had likely been killed by a sword blow to the head, and his daughter.</p>
<p>Our first question was: Do medieval Erfurt Jews and modern Ashkenazi Jews belong to the same genetic population? On average, yes. There has been almost no incorporation of genes from non-Jewish European populations over the last 600 years. </p>
<p>But the biggest surprise was that Erfurt Jews were noticeably more diverse than modern Ashkenazi Jews.</p>
<p>Some medieval individuals had greater Middle Eastern ancestry; they were genetically most similar to modern Ashkenazi Jews with origins in France and Germany.</p>
<p>Others had greater Eastern European ancestry, consistent with historical evidence that a number of people living in Erfurt between 1350 and 1400 had surnames indicating origins in the East, as well as Slavic given names.</p>
<p>The two groups – those with more Middle Eastern or more Slavic origins – also had distinct levels of <a href="https://en.wikipedia.org/wiki/%CE%9418O">oxygen isotopes</a> in their teeth, indicating they used different water sources in childhood, and thus, at least one of the groups must have included migrants. </p>
<p>Nevertheless, individuals from both groups were buried side by side, suggesting no social segregation.</p>
<p>Non-genetic research suggested that in the Middle Ages, Ashkenazi Jews were <a href="https://global.oup.com/academic/product/origins-of-yiddish-dialects-9780198739319">culturally divided into two major groups</a>. Western Jews lived in the Rhineland, where Ashkenazi Jews first settled. They may correspond to the Erfurt group with the greater Middle Eastern ancestry. Eastern Jews, from eastern Germany, Austria, Bohemia, Moravia and Silesia, may correspond to the Erfurt group with the greater Eastern European ancestry.</p>
<p>Erfurt was at the geographic boundary between the two medieval Jewish communities, and in the 14th century, it was likely a home to Jews belonging to both. This may explain our detection of two genetically distinguishable groups in one place.</p>
<p>Modern Ashkenazi Jews don’t show the medieval genetic heterogeneity. Instead, their genomes look like a nearly even mixture of the two Erfurt groups. Our genetic results fit with <a href="https://global.oup.com/academic/product/origins-of-yiddish-dialects-9780198739319">studies of names, dialects and religious rites</a>, which suggest that the Western and Eastern groups eventually merged and formed a single Ashkenazi culture.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/498061/original/file-20221129-18-uoe4mi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a man kneeling on pad on dirt works on something buried in the ground" src="https://images.theconversation.com/files/498061/original/file-20221129-18-uoe4mi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/498061/original/file-20221129-18-uoe4mi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/498061/original/file-20221129-18-uoe4mi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/498061/original/file-20221129-18-uoe4mi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/498061/original/file-20221129-18-uoe4mi.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=472&fit=crop&dpr=1 754w, https://images.theconversation.com/files/498061/original/file-20221129-18-uoe4mi.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=472&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/498061/original/file-20221129-18-uoe4mi.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=472&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">In advance of construction, archaeologists carefully excavated medieval remains so they could be respectfully reburied in a 19th century cemetery.</span>
<span class="attribution"><span class="source">Thuringian State Office for Heritage Management and Archaeology/Ronny Krause</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>A founder event left its genetic mark</h2>
<p>Our next question was whether Erfurt Jews show signs of the founder event so evident in the genes of modern Ashkenazi Jews.</p>
<p>They do. A stretch of genetic material called <a href="https://www.nature.com/scitable/topicpage/mtdna-and-mitochondrial-diseases-903/">mitochondrial DNA</a> is inherited only from mothers. Different people around the world today carry subtly different variations of it. One variant of mitochondrial DNA is found in 20% of modern Ashkenazi Jews and is nearly absent in non-Jewish populations. We identified it in 35% of the Erfurt individuals.</p>
<p>In other words, a third of the people we sampled from the graveyard descended, via their maternal line, from a single woman. That so many people share the same ancestral mother implies that the population must have been extremely small in the centuries before.</p>
<p>In the Erfurt individuals, we also found mutations common in Ashkenazi Jews today but extremely rare elsewhere, including 16 disease-causing mutations, one of them in the well-known BRCA1 gene. Another research group sequenced the genomes of <a href="https://doi.org/10.1016/j.cub.2022.08.036">six Ashkenazi Jews from 12th-century Norwich, England</a> and identified other disease mutations that are also still seen in Ashkenazi genomes today.</p>
<p>What was most striking about the founder event was how strongly the Erfurt Jews were affected. We estimate that the degree of relatedness of <a href="https://doi.org/10.1016/j.ajhg.2012.08.030">modern Ashkenazi Jewish genomes to each other</a> is about what would be expected if they descended from a population that had been persistently small throughout the second half of the Middle Ages. How small? We calculated that a core of only 1,000-2,000 reproducing people during this time would be responsible for most descendants today.</p>
<p>When we repeated a similar calculation using the Erfurt data, we encountered a surprise. Based on the medieval DNA, our estimate of the size of the founding population was about 3-fold smaller, only around 500 people. </p>
<p>How could it be that we were detecting the same founder event – responsible for the same disease-causing mutations in the Erfurt and in the modern Ashkenazi Jewish communities – and yet its impact on the Erfurt Jews was larger? </p>
<p>To address that, we proposed there were additional medieval Ashkenazi communities that inherited much less DNA from the core group of reproducing people we identified for Erfurt. We don’t yet know who these communities were, but our modeling suggests that they must have existed and later mixed with Erfurt-like communities, averaging together to form today’s Ashkenazi Jews.</p>
<p>So sometime after the 14th century, genetic barriers between Ashkenazi Jewish communities must have broken down, and the archipelago of scattered early Ashkenazi Jewish populations collapsed into the homogeneous group seen today. This was accompanied by extremely rapid population growth, which then continued for centuries. The Ashkenazi Jewish community, which had originally been demographically peripheral in the Jewish world, with its center of gravity around the Mediterranean and the Middle East, eventually became the largest world population of Jews.</p>
<h2>A template for future studies</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/497962/original/file-20221129-16-tumege.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="view of an old stone building through a stone arch" src="https://images.theconversation.com/files/497962/original/file-20221129-16-tumege.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/497962/original/file-20221129-16-tumege.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=688&fit=crop&dpr=1 600w, https://images.theconversation.com/files/497962/original/file-20221129-16-tumege.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=688&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/497962/original/file-20221129-16-tumege.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=688&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/497962/original/file-20221129-16-tumege.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=865&fit=crop&dpr=1 754w, https://images.theconversation.com/files/497962/original/file-20221129-16-tumege.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=865&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/497962/original/file-20221129-16-tumege.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=865&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The Old Synagogue of the medieval Jewish community of Erfurt is now a museum documenting past Jewish life in Erfurt.</span>
<span class="attribution"><span class="source">Stadt Erfurt Marcel Krummrich</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Erfurt and Norwich are just two locations. A richer picture of medieval Ashkenazi Jewish history will require sampling additional sites. How Ashkenazi Jews relate to Sephardi Jews and the many other living Jewish communities, and how all of these communities relate to Roman-period Judeans, are mysteries that ancient DNA research may also one day address. Any such research would need to take into account modern community sensitivities, and we think our work in Erfurt is a good model.</p>
<p>More broadly, this work provides a template for how ancient DNA, even from individuals who lived relatively recently, can reveal aspects of history that are otherwise invisible. By carrying out such studies, scholars can help reveal the roots of modern groups, enriching people’s understanding of themselves and each other.</p><img src="https://counter.theconversation.com/content/194780/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shai Carmi received funding for this study from the Israel Science Foundation and the United States-Israel Binational Science Foundation. He is a paid consultant at MyHeritage.</span></em></p><p class="fine-print"><em><span>David Reich receives funding for his research from the US National Institutes of Health, the Allen Discovery Center program (a Paul G. Allen Frontiers Group advised program of the Paul G. Allen Family Foundation), the John Templeton Foundation; a private gift from Jean-François Clin, and the Howard Hughes Medical Institute.</span></em></p>
A German town needed to relocate a medieval graveyard to build a parking garage. A positive side effect: Scientists got to sequence the DNA of Ashkenazi Jews who lived more than 600 years ago.
Shai Carmi, Associate Professor of Population and Statistical Genetics, Hebrew University of Jerusalem
David Reich, Professor of Genetics and of Human Evolutionary Biology, Harvard University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/192595
2022-10-19T19:05:47Z
2022-10-19T19:05:47Z
First-ever genetic analysis of a Neanderthal family paints a fascinating picture of a close-knit community
<figure><img src="https://images.theconversation.com/files/489930/original/file-20221017-17-4qvy1b.jpg?ixlib=rb-1.1.0&rect=11%2C0%2C1243%2C718&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Neanderthal father and his daughter.</span> <span class="attribution"><span class="source">Tom Björklund</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Our closest evolutionary relatives, the Neanderthals (<em>Homo neanderthalensis</em>), were once spread across Europe and as far east as the Altai Mountains in southern Siberia.</p>
<p>Yet more than 160 years since the first Neanderthal fossils were unearthed in Europe, little is known about the group size or social organisation of Neanderthal communities.</p>
<p>Using ancient DNA, a <a href="https://www.nature.com/articles/s41586-022-05283-y">new study</a> provides a snapshot of a Neanderthal community frozen in time.</p>
<p>With our colleagues, we show a group of Neanderthals living in the Altai foothills around 54,000 years ago consisted of perhaps 10 to 20 individuals. Many of them were closely related – including a father and his young daughter.</p>
<h2>The easternmost Neanderthals</h2>
<p>The first genetic clues to Neanderthals were obtained <a href="https://www.cell.com/fulltext/S0092-8674(00)80310-4">25 years ago</a> from a fragment of mitochondrial DNA, which is found in cell structures called mitochondria rather than in the cell nucleus.</p>
<p>Subsequent mitochondrial DNA studies and genome-wide nuclear data from 18 individuals have sketched the broad brushstrokes of Neanderthal history, revealing the existence of many genetically distinct groups between about 430,000 and 40,000 years ago.</p>
<p>Our new study is the first to analyse ancient DNA from the teeth and bones of multiple Neanderthals who lived at around the same time. The fossils came from archaeological excavations of Okladnikov Cave in the mid-1980s and Chagyrskaya Cave since 2007.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/489936/original/file-20221017-12-8falkc.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A map showing locations of the caves and a photo of one of them" src="https://images.theconversation.com/files/489936/original/file-20221017-12-8falkc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489936/original/file-20221017-12-8falkc.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=343&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489936/original/file-20221017-12-8falkc.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=343&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489936/original/file-20221017-12-8falkc.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=343&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489936/original/file-20221017-12-8falkc.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=431&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489936/original/file-20221017-12-8falkc.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=431&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489936/original/file-20221017-12-8falkc.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=431&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Neanderthal DNA was sequenced from fossil remains found at Chagyrskaya Cave (photo) and Okladnikov Cave in southern Siberia.</span>
<span class="attribution"><span class="source">Maciej Krajcarz (map) and Richard Roberts (photo)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>These caves were used by Neanderthals as hunting camps. The remains of animals such as bison and horses are abundant, and more than 80 Neanderthal fossils were also found in Chagyrskaya Cave – one of the largest such collections anywhere in the world.</p>
<p>Both sites also contain <a href="https://www.pnas.org/doi/10.1073/pnas.1918047117">distinctive stone tools</a> that bear a striking resemblance to artefacts found at Neanderthal sites in central and eastern Europe.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/stone-tools-reveal-epic-trek-of-nomadic-neanderthals-129886">Stone tools reveal epic trek of nomadic Neanderthals</a>
</strong>
</em>
</p>
<hr>
<h2>Family ties</h2>
<p>To paint a detailed picture of the genetic makeup and relatedness of these Neanderthals, we analysed mitochondrial DNA (which is passed down the female line), Y-chromosomes (passed from father to son) and genome-wide data (inherited from both parents) for 17 Neanderthal fossils – the most ever sequenced in a single study.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/489916/original/file-20221017-25-a1wd6b.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A range of bones and teeth on a dark background" src="https://images.theconversation.com/files/489916/original/file-20221017-25-a1wd6b.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489916/original/file-20221017-25-a1wd6b.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=278&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489916/original/file-20221017-25-a1wd6b.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=278&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489916/original/file-20221017-25-a1wd6b.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=278&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489916/original/file-20221017-25-a1wd6b.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=350&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489916/original/file-20221017-25-a1wd6b.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=350&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489916/original/file-20221017-25-a1wd6b.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=350&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Neanderthal teeth and bones from Chagyrskaya Cave (A, B) and Okladnikov Cave (C) included in our study. The white bar in each panel is 1 cm in length.</span>
<span class="attribution"><span class="source">Bence Viola</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>The teeth and bones came from 13 individuals: 11 from Chagyrskaya Cave and two from Okladnikov Cave. Seven of the Neanderthals were male and six were female. Eight were adults and five were children or adolescents.</p>
<p>Among them were the remains of a Neanderthal father and his teenage daughter, as well as a pair of second-degree relatives – a young boy and an adult female, perhaps his cousin, aunt or grandmother.</p>
<p>Although the nearby site of <a href="https://theconversation.com/fresh-clues-to-the-life-and-times-of-the-denisovans-a-little-known-ancient-group-of-humans-110504">Denisova Cave</a> was inhabited by Neanderthals from as early as 200,000 years ago, the Chagyrskaya and Okladnikov Neanderthals are more closely related to European Neanderthals than to the earlier ones at Denisova Cave.</p>
<p>This finding is consistent with a <a href="https://www.pnas.org/doi/10.1073/pnas.2004944117">previous genomic study</a> of a Chagyrskaya Neanderthal and the presence of distinctive stone tools at Chagyrskaya and Okladnikov Caves that closely resemble those found at Neanderthal sites in Europe.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/490089/original/file-20221017-7429-yw50nu.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="A graph showing relations among the various species" src="https://images.theconversation.com/files/490089/original/file-20221017-7429-yw50nu.png?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/490089/original/file-20221017-7429-yw50nu.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=643&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490089/original/file-20221017-7429-yw50nu.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=643&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490089/original/file-20221017-7429-yw50nu.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=643&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490089/original/file-20221017-7429-yw50nu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=808&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490089/original/file-20221017-7429-yw50nu.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=808&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490089/original/file-20221017-7429-yw50nu.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=808&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Phylogenetic tree of mitochondrial DNA sequences showing the evolutionary relationships among the Chagyrskaya (blue) and Okladnikov (orange) Neanderthals included in our study, Neanderthals from Denisova Cave and Europe, and present-day humans from Africa, East Asia and Europe.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We also found the Chagyrskaya Neanderthals share several heteroplasmies – a special kind of mitochondrial DNA variant that typically persists for less than three generations.</p>
<p>Taken together with the evidence for their close family connections, these indicate the Chagyrskaya Neanderthals must have lived – and died – at around the same time.</p>
<h2>On the brink of extinction</h2>
<p>Our analyses also revealed this Neanderthal community had extremely low genetic diversity – consistent with a group size of just 10 to 20 people.</p>
<p>This is much smaller than the genetic diversity recorded for any ancient or present-day human community, and is more like that found among endangered species at risk of extinction, such as <a href="https://www.worldwildlife.org/species/mountain-gorilla">mountain gorillas</a>.</p>
<p>The Chagyrskaya Neanderthals were not a community of hermits, however. We discovered their mitochondrial DNA diversity was much higher than their Y-chromosome diversity, which can be explained by the predominance of female (rather than male) migration between Neanderthal communities.</p>
<p>Did these migrations involve Denisovans, who occupied Denisova Cave repeatedly from at least 250,000 years ago to around 50,000 years ago?</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/dirty-secrets-sediment-dna-reveals-a-300-000-year-timeline-of-ancient-and-modern-humans-living-in-siberia-161585">Dirty secrets: sediment DNA reveals a 300,000-year timeline of ancient and modern humans living in Siberia</a>
</strong>
</em>
</p>
<hr>
<p>Denisovans are a sister group to Neanderthals and they interbred at least once. This happened around 100,000 years ago, <a href="https://www.nature.com/articles/d41586-018-06004-0">producing a daughter</a> from a Neanderthal mother and a Denisovan father.</p>
<p>Yet even though Denisovans were present at Denisova Cave at around the same time as the Neanderthals living at Chagyrskaya and Okladnikov Caves, we found no evidence for Denisovan gene flow into these Neanderthals in the 20,000 years leading up to their demise.</p>
<h2>Kindred spirits</h2>
<p>In recent years, multiple lines of evidence have shown Neanderthals possessed <a href="https://theconversation.com/neanderthals-were-no-brutes-research-reveals-they-may-have-been-precision-workers-103858">technical skills</a>, <a href="https://theconversation.com/how-we-discovered-that-neanderthals-could-make-art-92127">cognitive capabilities</a> and <a href="https://www.nature.com/articles/s41559-021-01487-z">symbolic behaviours</a> as impressive as those of our ancient <em>Homo sapiens</em> ancestors.</p>
<p>Our genetic insights add a new social dimension to this picture. They provide a rare glimpse into the close-knit family structure of a Neanderthal community eking out an existence on the eastern frontier of their geographic range, close to the time when their species finally died out.</p><img src="https://counter.theconversation.com/content/192595/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard 'Bert' Roberts receives funding from the Australian Research Council.</span></em></p><p class="fine-print"><em><span>Laurits Skov does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Ancient DNA from Neanderthal fossils in southern Siberia reveals a small community with close family ties – including a father and his teenage daughter.
Laurits Skov, Postdoctoral research associate, Max Planck Institute for Evolutionary Anthropology
Richard 'Bert' Roberts, Director, ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH), University of Wollongong
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/188886
2022-10-10T00:32:46Z
2022-10-10T00:32:46Z
From coelacanths to crinoids: these 9 ‘living fossils’ haven’t changed in millions of years
<figure><img src="https://images.theconversation.com/files/488446/original/file-20221006-18-3hvthi.jpeg?ixlib=rb-1.1.0&rect=6%2C0%2C4198%2C2797&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>We see evolution all around us, constantly, in every living thing. Yet in the deep oceans we find a number of “living fossils” reminiscent of creatures from prehistoric times. </p>
<p>In his 1859 book <a href="https://en.wikipedia.org/wiki/On_the_Origin_of_Species">On the Origin of Species</a>, esteemed naturalist Charles Darwin coined the term “living fossil” to describe living organisms that appeared unchanged from their extinct fossil relatives. The term has since been used to describe long-enduring lineages, <a href="https://www.collinsdictionary.com/dictionary/english/relict">relict</a> populations, groups with low diversity, and groups with DNA that has hardly changed in millions of years.</p>
<p>The marine depths seem to be a good place for “living fossils”, with cartilaginous fish such as sharks and rays generally being 2-4 times more <a href="https://www.nature.com/articles/s41559-017-0448-4">evolutionarily distinct</a> than land animals. In other words, while every species is unique, these species are <em>particularly</em> unlike their closest relatives. </p>
<p>Let’s take a look at some of these relics from the past.</p>
<p><strong>1. Coelacanth</strong></p>
<p><a href="https://en.wikipedia.org/wiki/Coelacanth">Coelacanths</a> are fish that live deep off the coasts of Africa and Indonesia. They have unusually shaped paired body fins which they move alternatively, almost as if they’re “walking” underwater. Their lineage stretches back to the Devonian Period, at least 410 million years ago. </p>
<p>It was once thought coelacanths had gone extinct alongside (non-bird) dinosaurs about 70 million years ago, as they disappear from the fossil record around this time. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482247/original/file-20220901-21-pgqjye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482247/original/file-20220901-21-pgqjye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=280&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482247/original/file-20220901-21-pgqjye.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=280&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482247/original/file-20220901-21-pgqjye.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=280&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482247/original/file-20220901-21-pgqjye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=352&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482247/original/file-20220901-21-pgqjye.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=352&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482247/original/file-20220901-21-pgqjye.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=352&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Allenypterus montanus</em>, a fossil coelacanth fish from the Bear Gulch Limestone in Montana.</span>
<span class="attribution"><span class="source">James St. John</span></span>
</figcaption>
</figure>
<p>So imagine the surprise when <a href="https://www.nature.com/articles/143455a0">a living specimen</a> was dredged up from the deep ocean in 1938! This fish became <a href="https://www.goodreads.com/en/book/show/11297431">known</a> as “Old Fourlegs” and was thought to be the direct fishy ancestor of all land animals (although we now know this isn’t strictly correct). </p>
<p>Today there are two living coelacanth species, known as <em>Latimeria</em>, which have basically remained unchanged over the past <a href="https://www.nature.com/articles/nature12027">100 million years</a>.</p>
<p><strong>2. Horseshoe crab</strong></p>
<p><a href="https://en.wikipedia.org/wiki/Horseshoe_crab">Horseshoe crabs</a> are ancient creatures that first appeared at least 480 million years ago <a href="https://www.frontiersin.org/articles/10.3389/feart.2020.00098/full">during the Ordovician Period</a> and don’t appear to have changed much since. They are not crabs at all, but “chelicerates” and therefore more closely related to spiders and sea scorpions. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482232/original/file-20220901-18-xgvq5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482232/original/file-20220901-18-xgvq5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482232/original/file-20220901-18-xgvq5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482232/original/file-20220901-18-xgvq5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482232/original/file-20220901-18-xgvq5d.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482232/original/file-20220901-18-xgvq5d.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482232/original/file-20220901-18-xgvq5d.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">You can find Horseshoe crabs at Bowers Beach in Delaware.</span>
<span class="attribution"><span class="source">Jeffrey</span></span>
</figcaption>
</figure>
<p>There are four species alive today, all within the family Limulidae, found in waters off Asia and North America. They migrate to shallow coastal waters to breed in massive “orgy” events, with females laying many tens of thousands of eggs in the sand. </p>
<p>They also have strange blue blood, coloured that way due to a high copper content. Horseshoe crabs are harvested for their blood by the pharmaceutical industry since it has uses in biomedical testing. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482400/original/file-20220901-18492-pgqjye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482400/original/file-20220901-18492-pgqjye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=395&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482400/original/file-20220901-18492-pgqjye.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=395&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482400/original/file-20220901-18492-pgqjye.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=395&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482400/original/file-20220901-18492-pgqjye.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=496&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482400/original/file-20220901-18492-pgqjye.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=496&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482400/original/file-20220901-18492-pgqjye.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=496&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Mesolimulus walchi</em> is an extinct species of horseshoe crab.</span>
<span class="attribution"><span class="source">Petr Hykš</span></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/living-fossils-we-mapped-half-a-billion-years-of-horseshoe-crabs-to-save-them-from-blood-harvests-141042">'Living fossils': we mapped half a billion years of horseshoe crabs to save them from blood harvests</a>
</strong>
</em>
</p>
<hr>
<p><strong>3. Elephant shark</strong></p>
<p>Similar to horseshoe crabs, “<a href="https://en.wikipedia.org/wiki/Australian_ghostshark">elephant shark</a>” (<em>Callorhinchus milii</em>) is a misnomer. This species, also known as the Australian ghost shark, is not a shark at all. It’s a related type of cartilaginous fish known as a “chimaera” and belongs to a subclass called Holocephali which diverged from the shark lineage more than 450 million years ago. </p>
<p>These “plownose” chimaeras take their name from their bizarrely shaped snout and can be found living off the continental shelves of Australia and New Zealand. </p>
<p>Analysis of their genome has shown the species changes at a veritable snail’s pace. In fact, it has <a href="https://www.nature.com/articles/nature12826">the slowest</a> evolving genome of all vertebrates, with its DNA almost imperceptibly altered over hundreds of millions of years. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482233/original/file-20220901-26-k2vijd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482233/original/file-20220901-26-k2vijd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=265&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482233/original/file-20220901-26-k2vijd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=265&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482233/original/file-20220901-26-k2vijd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=265&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482233/original/file-20220901-26-k2vijd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=333&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482233/original/file-20220901-26-k2vijd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=333&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482233/original/file-20220901-26-k2vijd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=333&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Callorhinchus milii</em> is covered in distinct dark markings. It is commercially exploited in Australia.</span>
<span class="attribution"><span class="source">Totti/Wikimedia</span></span>
</figcaption>
</figure>
<p><strong>4. Nautilus</strong></p>
<p><a href="https://en.wikipedia.org/wiki/Nautilus">Nautilus</a> are a type of marine cephalopod mollusc, and are therefore related to squid and octopus. However, unlike other cephalopods, they are housed within a distinctive smooth, hard shell. </p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/482235/original/file-20220901-2706-r757cr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/482235/original/file-20220901-2706-r757cr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482235/original/file-20220901-2706-r757cr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482235/original/file-20220901-2706-r757cr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482235/original/file-20220901-2706-r757cr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482235/original/file-20220901-2706-r757cr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482235/original/file-20220901-2706-r757cr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"><em>Nautilus</em> live in the ‘pelagic’ zone, the large middle column of water that’s far from both the shore and ocean bottom.</span>
<span class="attribution"><span class="source">PacificKlaus</span></span>
</figcaption>
</figure>
<p>Nautilus live in the <a href="https://oceanservice.noaa.gov/facts/pelagic.html">open water</a> in and around coral reefs in the Indo-Pacific Ocean. They’re hunted for their beautiful shells to make art and jewellery, but international trade is now regulated to protect them from over-exploitation. </p>
<p><a href="https://www.fisheries.noaa.gov/species/chambered-nautilus#">Members of</a> the Nautilidae family are known to have existed from the Late Triassic, and appear to have remained relatively unchanged for more than 200 million years. Darwin himself described these creatures as “<a href="https://www.taylorfrancis.com/books/mono/10.4324/9780203509104/origin-species-1859-charles-darwin">living fossils</a>”.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482246/original/file-20220901-17-5h32v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482246/original/file-20220901-17-5h32v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=392&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482246/original/file-20220901-17-5h32v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=392&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482246/original/file-20220901-17-5h32v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=392&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482246/original/file-20220901-17-5h32v.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=493&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482246/original/file-20220901-17-5h32v.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=493&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482246/original/file-20220901-17-5h32v.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=493&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">You’d struggle to tell an ancient <em>Nautilus</em> from a living one.</span>
</figcaption>
</figure>
<p><strong>5. Goblin shark</strong> </p>
<p>The <a href="https://en.wikipedia.org/wiki/Goblin_shark">goblin shark</a> (<em>Mitsukurina owstoni</em>) is a bizarre animal with a long, flat snout and toothy jaws that protrude in front of the face to catch unsuspecting prey. It’s a relatively rare deep-water shark living in all major oceans. With a face only a mother could love, it was described as “<a href="https://www.jstor.org/stable/26037101#metadata_info_tab_contents">grotesque</a>” when first encountered in 1910. </p>
<p>The goblin shark is the only living representative of its family, Mitsukurinidae, and is the most evolutionarily distinct shark we know of; its lineage stretches back some <a href="https://www.nature.com/articles/s41559-017-0448-4">125 million years</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/482236/original/file-20220901-22-bay3gl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/482236/original/file-20220901-22-bay3gl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482236/original/file-20220901-22-bay3gl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482236/original/file-20220901-22-bay3gl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482236/original/file-20220901-22-bay3gl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482236/original/file-20220901-22-bay3gl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482236/original/file-20220901-22-bay3gl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482236/original/file-20220901-22-bay3gl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Goblin sharks are rarely seen by humans.</span>
<span class="attribution"><span class="source">Dianne Bray/Museum Victoria</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p><strong>6. Mantis shrimp</strong></p>
<p><a href="https://en.wikipedia.org/wiki/Mantis_shrimp">Mantis shrimp</a>, also called stomatopods, are distinctive crustaceans found in tropical and subtropical coastal waters around the world. They are fearsome marine carnivores known to deliver a dizzyingly fast and painful blow.</p>
<p>They also live a colourful life. During mating season they fluoresce (emit light) and have complex eyes to watch these displays. In fact, they have up to 16 colour receptors, whereas humans have just three.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482237/original/file-20220901-16-748b65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482237/original/file-20220901-16-748b65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=534&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482237/original/file-20220901-16-748b65.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=534&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482237/original/file-20220901-16-748b65.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=534&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482237/original/file-20220901-16-748b65.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=670&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482237/original/file-20220901-16-748b65.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=670&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482237/original/file-20220901-16-748b65.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=670&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Mantis shrimp have the fastest self-powered strike in the animal kingdom.</span>
<span class="attribution"><span class="source">PiktourUK</span></span>
</figcaption>
</figure>
<p>The mantis shrimp lineage branched off from other crustaceans in the malacostraca class (such as crabs, lobsters and krill) during the Carboniferous, around 340 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5610894/">million years ago</a>. So these fabulous, feisty critters have been flourishing for a long time. Today there are hundreds of species belonging to the suborder Unipeltata, which appeared some 190 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5610894/">million years ago</a>. </p>
<p><strong>7. Striped panray</strong> </p>
<p>Many cartilaginous fish tend to be highly evolutionarily distinct, but taking out the top spot is the striped panray (<em>Zanobatus schoenleinii</em>). This fish has a median “evolutionary distinctiveness” age of <a href="https://www.nature.com/articles/s41559-017-0448-4">188 million years</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/482238/original/file-20220901-24-r757cr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/482238/original/file-20220901-24-r757cr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/482238/original/file-20220901-24-r757cr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=861&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482238/original/file-20220901-24-r757cr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=861&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482238/original/file-20220901-24-r757cr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=861&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482238/original/file-20220901-24-r757cr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1083&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482238/original/file-20220901-24-r757cr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1083&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482238/original/file-20220901-24-r757cr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1083&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A striped panray illustration from 1841.</span>
<span class="attribution"><a class="source" href="https://www.biodiversitylibrary.org/page/6353171#page/288/mode/1up">Müller and Henle (1841)/Wikimedia</a></span>
</figcaption>
</figure>
<p>Today, the striped panray lives in tropical waters in the eastern Atlantic (and possibly the Indian) ocean, and feeds on small invertebrates from the <a href="https://books.google.com.au/books?hl=en&lr=&id=Ds6sDQAAQBAJ&oi=fnd&pg=PP1&dq=rays+of+the+world+csiro&ots=Px_ASMM0iJ&sig=amnsW_Yj6mNcCGrUtLi_EaKEeP0#v=onepage&q=rays%20of%20the%20world%20csiro&f=false">ocean floor</a>. It belongs to the order Rhinopristiformes and is ovoviviparous, meaning it gives birth to live young. It is listed as “vulnerable” by the <a href="https://www.iucnredlist.org/">International Union for Conservation of Nature</a>.</p>
<p><strong>8. Brachiopods</strong></p>
<p><a href="https://en.wikipedia.org/wiki/Lingula_(brachiopod)">Brachiopods</a> are shelly marine animals with long, fleshy stalks that live in burrows on the seafloor. They act as reef-dwelling organisms, filter-feeding from the water around them. Brachiopods living today, such as <em>Lingula</em>, look more or less the same as their Cambrian counterparts from about 500 million years ago! They are considered the oldest known animal (genus) that still contains <a href="https://ucmp.berkeley.edu/brachiopoda/brachiopodafr.html">living representatives</a>. </p>
<p>In The Origin of Species, Darwin <a href="https://www.taylorfrancis.com/books/mono/10.4324/9780203509104/origin-species-1859-charles-darwin">noted</a> “some of the most ancient […] animals as […] <em>Nautilus, Lingula</em>, etc., do not differ much from living species”. It’s these observations that led him to propose the term “living fossil”. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482428/original/file-20220902-15-fxya00.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482428/original/file-20220902-15-fxya00.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=449&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482428/original/file-20220902-15-fxya00.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=449&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482428/original/file-20220902-15-fxya00.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=449&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482428/original/file-20220902-15-fxya00.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=564&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482428/original/file-20220902-15-fxya00.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=564&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482428/original/file-20220902-15-fxya00.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=564&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Brachiopods have hardly changed in hundreds of millions of years.</span>
<span class="attribution"><span class="source">Rob Growler</span></span>
</figcaption>
</figure>
<p><strong>9. Crinoids</strong> </p>
<p>Crinoids are known from at least the Devonian (359-419 million years ago) but may have existed as long ago as the Ordovician (more than 445 million). These marine animals, also known as “sea lilies”, once lived on the seafloor in a symbiotic relationship with corals. Corals grew off the stalks of crinoids to reach higher into the water column for better feeding opportunities. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482244/original/file-20220901-17-9gm6n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482244/original/file-20220901-17-9gm6n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482244/original/file-20220901-17-9gm6n9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482244/original/file-20220901-17-9gm6n9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482244/original/file-20220901-17-9gm6n9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482244/original/file-20220901-17-9gm6n9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482244/original/file-20220901-17-9gm6n9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A fossil crinoid species called <em>Seirocrinus subangularis</em>.</span>
<span class="attribution"><span class="source">James St. John</span></span>
</figcaption>
</figure>
<p>This association was very common until it seemingly stopped appearing in the fossil record about 273 million years ago. However, in 2021 these two marine creatures were rediscovered in Japanese waters, thriving in a blissful aquatic <a href="https://www.sciencedirect.com/science/article/pii/S0031018221002042?via%3Dihub">partnership</a>. It remains a mystery why no fossil evidence of this happy marriage had been found for the intervening period.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482241/original/file-20220901-26-oi4w5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482241/original/file-20220901-26-oi4w5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482241/original/file-20220901-26-oi4w5z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482241/original/file-20220901-26-oi4w5z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482241/original/file-20220901-26-oi4w5z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482241/original/file-20220901-26-oi4w5z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482241/original/file-20220901-26-oi4w5z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Crinoids were thought to be extinct until 2021.</span>
<span class="attribution"><span class="source">NOAA Ocean Exploration and Research</span></span>
</figcaption>
</figure>
<h2>How do living fossils form?</h2>
<p>While animals described as “living fossils” usually do continue to evolve, many of these changes are imperceptible to the human eye. To track how animals change over time, we look at molecular changes visible in the genes, or “morphological” changes to the physical form. </p>
<p>Internal (or molecular) drivers include <a href="https://en.wikipedia.org/wiki/Genetic_drift">genetic drift</a>, which is the random change in the frequency of gene variants in a population over time. External forces include <a href="https://en.wikipedia.org/wiki/Natural_selection">natural selection</a>, in particular sexual selection, which lead to specific traits being inherited in a population over time. </p>
<p>All the marine animals in this list seem to be undergoing morphological stasis (slowing or stoppage). Some may have molecular stasis too. Their slowing rates of evolution are likely a result of the relatively stable environment underwater, particularly in the deep sea. These distant refuges are some of the least affected by direct human impacts and changes in weather and climate. </p>
<p>Then again, these animals are not immune. And if we’re not careful, we may lose some of these curious creatures forever.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/482214/original/file-20220901-22-4ezpjr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/482214/original/file-20220901-22-4ezpjr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/482214/original/file-20220901-22-4ezpjr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/482214/original/file-20220901-22-4ezpjr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/482214/original/file-20220901-22-4ezpjr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/482214/original/file-20220901-22-4ezpjr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/482214/original/file-20220901-22-4ezpjr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A <em>Latimeria</em> (coelacanth) specimen at the South African Institute for Aquatic Biodiversity, and an excited human.</span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/sea-monsters-were-real-millions-of-years-ago-new-fossils-tell-about-their-rise-and-fall-191089">'Sea monsters' were real millions of years ago. New fossils tell about their rise and fall</a>
</strong>
</em>
</p>
<hr>
<p><em>Correction: this article previously said crinoids seemingly went extinct 273 million years ago. It has been amended to clarify their symbiotic relationship with corals is what vanished at this time — and not crinoids themselves. Also, brachiopods were previously described as “reef-builders”, but this wording has been changed to “reef-dwellers”.</em></p><img src="https://counter.theconversation.com/content/188886/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alice Clement receives funding from the Australian Research Council. </span></em></p>
Deep in the oceans dwell creatures that can evade many of the evolutionary drivers of life on land – and they remain seemingly unchanged through time.
Alice Clement, Research Associate in the College of Science and Engineering, Flinders University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/191913
2022-10-07T12:22:44Z
2022-10-07T12:22:44Z
Our ‘Homo sapiens’ ancestors shared the world with Neanderthals, Denisovans and other types of humans whose DNA lives on in our genes
<figure><img src="https://images.theconversation.com/files/488681/original/file-20221007-12-xnxe5b.jpg?ixlib=rb-1.1.0&rect=22%2C11%2C2320%2C1616&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Hundreds of thousands of years ago, our *Homo sapiens* ancestors shared the landscape with multiple other hominins.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-exhibit-hall-includes-more-than-75-skulls-including-two-news-photo/129710842">The Washington Post via Getty Images</a></span></figcaption></figure><p>When the <a href="https://www.livescience.com/how-many-human-species.html">first modern humans arose</a> in East Africa sometime between 200,000 and 300,000 years ago, the world was very different compared to today. Perhaps the biggest difference was that we – meaning people of our species, <em>Homo sapiens</em> – were only one of several types of humans (or <a href="https://australian.museum/learn/science/human-evolution/hominid-and-hominin-whats-the-difference/">hominins</a>) that simultaneously existed on Earth.</p>
<p>From the well-known <a href="https://humanorigins.si.edu/evidence/genetics/ancient-dna-and-neanderthals">Neanderthals</a> and <a href="https://theconversation.com/fresh-clues-to-the-life-and-times-of-the-denisovans-a-little-known-ancient-group-of-humans-110504">more enigmatic Denisovans</a> in Eurasia, to the diminutive <a href="https://theconversation.com/the-hobbits-were-extinct-much-earlier-than-first-thought-56922">“hobbit” <em>Homo floresiensis</em></a> on the island of Flores in Indonesia, to <a href="https://theconversation.com/i-was-part-of-the-team-that-found-the-homo-naledi-childs-skull-how-we-did-it-171153"><em>Homo naledi</em> that lived in South Africa</a>, multiple hominins abounded.</p>
<p>Then, between 30,000 and 40,000 years ago, <a href="https://flexbooks.ck12.org/cbook/ck-12-college-human-biology-flexbook-2.0/section/7.6/primary/lesson/neanderthals-and-other-archaic-humans-chumbio/">all but one type of these hominins disappeared</a>, and for the first time we were alone.</p>
<p>Until recently, one of the mysteries about human history was whether our ancestors interacted and mated with these other types of humans before they went extinct. This fascinating question was the subject of great and often contentious <a href="https://www.sfgate.com/science/article/Neanderthal-love-Scientists-split-over-how-much-2626826.php">debates among scientists for decades</a>, because the data needed to answer this question simply didn’t exist. In fact, it seemed to many that the data would never exist.</p>
<p><a href="https://scholar.google.com/citations?user=_Urs-74AAAAJ&hl=en&oi=ao">Svante Pääbo</a>, however, paid little attention to what people thought was or was not possible. His persistence in developing tools to extract, sequence and interpret ancient DNA enabled sequencing the genomes of <a href="https://doi.org/10.1126/science.1188021">Neanderthals</a>, <a href="https://www.nature.com/articles/nature09710">Denisovans</a> and <a href="https://doi.org/10.1038/nature14558">early modern humans</a> who lived over 45,000 years ago.</p>
<p><a href="https://www.nobelprize.org/prizes/medicine/2022/press-release/">For developing this new field of paleogenomics</a>, Pääbo was awarded the 2022 Nobel Prize in Physiology or Medicine. This honor is not only well-deserved recognition for Pääbo’s triumphs, but also for evolutionary genomics and the insights it can contribute toward a more comprehensive understanding of human health and disease.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/488774/original/file-20221007-24-40vkma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Diagram of human lineages diverging and interbreeding over time" src="https://images.theconversation.com/files/488774/original/file-20221007-24-40vkma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488774/original/file-20221007-24-40vkma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=621&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488774/original/file-20221007-24-40vkma.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=621&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488774/original/file-20221007-24-40vkma.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=621&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488774/original/file-20221007-24-40vkma.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=780&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488774/original/file-20221007-24-40vkma.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=780&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488774/original/file-20221007-24-40vkma.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=780&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A simplified model of human evolution showing how humans are related to Neanderthals and Denisovans. Arrows between different branches show mating that occurred. Events that happened further back in time are closer to the top of the image.</span>
<span class="attribution"><span class="source">Joshua Akey</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Mixing and mating, revealed by DNA</h2>
<p>Genetic studies of living people over the past several decades revealed the general contours of human history. Our species arose in Africa, dispersing out from that continent around 60,000 years ago, ultimately spreading to nearly all habitable places on Earth. Other types of humans existed as modern humans migrated throughout the world, but the genetic data showed little evidence that modern humans mated with other hominins.</p>
<p>Over the past decade, however, the study of ancient DNA, recovered from fossils up to around <a href="https://www.scientificamerican.com/article/oldest-ancient-human-dna-details-dawn-of-neandertals/">400,000 years old</a>, has revealed startling new twists and turns in the story of human history. </p>
<p>For example, the Neanderthal genome provided the data necessary to definitively show that humans and Neanderthals mated. Non-African people alive today inherited about <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5772775/">2% of their genomes</a> from Neanderthal ancestors, thanks to this kind of interbreeding.</p>
<p>In one of the biggest surprises, when Pääbo and his colleagues sequenced ancient DNA obtained from a small finger bone fragment that was assumed to be Neanderthal, it turned out to be an entirely <a href="https://doi.org/10.1038/nature09710">unknown type of human, now called Denisovans</a>. <a href="https://nautil.us/the-human-family-tree-it-turns-out-is-complicated-238239/">Humans and Denisovans also mated</a>, with the highest levels of Denisovan ancestry present today – between 4% and 6% – in individuals of Oceanic ancestry.</p>
<p>Strikingly, ancient DNA from a 90,000-year-old female revealed that she had <a href="https://doi.org/10.1038/d41586-018-06004-0">a Neanderthal mother and a Denisovan father</a>. Although there are still many unanswered questions, the picture emerging from analyses of ancient and modern DNA is that not only did multiple hominins overlap in time and space, but that matings were relatively common.</p>
<h2>Archaic genes you carry today</h2>
<p>Estimating the proportion of ancestry that modern individuals have from Neanderthals or Denisovans is certainly interesting. But ancestry proportions provide limited information about the consequences of these ancient matings.</p>
<p>For instance, does DNA inherited from Neanderthals and Denisovans influence biological functions that occur within our cells? Does this DNA influence traits like eye color or susceptibility to disease? Were DNA sequences from our evolutionary cousins ever beneficial, helping humans adapt to new environments?</p>
<p>To answer these questions, we need to identify the bits of Neanderthal and Denisovan DNA scattered throughout the genomes of modern individuals.</p>
<p>In 2014, <a href="https://akeylab.princeton.edu">my group</a> and <a href="https://reich.hms.harvard.edu">David Reich’s group</a> independently published the <a href="https://www.science.org/doi/10.1126/science.1245938">first maps of</a> <a href="https://www.nature.com/articles/nature12961">Neanderthal sequences</a> that survive in the DNA of modern humans. Today, roughly 40% of the Neanderthal genome has been recovered not by sequencing ancient DNA recovered from a fossil, but indirectly by <a href="https://doi.org/10.1016/j.cub.2022.08.027">piecing together the Neanderthal sequences</a> that persist in the genomes of contemporary individuals.</p>
<p>Similarly, in 2016 <a href="https://doi.org/10.1126/science.aad9416">my group</a> and <a href="https://doi.org/10.1016/j.cub.2016.03.037">David Reich’s group</a> published the first comprehensive catalogs of DNA sequences in modern individuals inherited from Denisovan ancestors. Surprisingly, when we analyzed the Denisovan sequences that persist in people today, we discovered they came from two distinct Denisovan populations, and therefore at least <a href="https://doi.org/10.1016/j.cell.2018.02.031">two separate waves of matings occurred between Denisovans and modern humans</a>. </p>
<p>The analysis of Neanderthal and Denisovan DNA in modern humans reveals that some of their sequence was harmful and rapidly got purged from human genomes. In fact, the initial fraction of Neanderthal ancestry in humans who lived approximately 45,000 years ago was around 10%. That amount rapidly declined over a small number of generations to the 2% <a href="https://doi.org/10.1073/pnas.1814338116">observed in contemporary individuals</a>.</p>
<p>The removal of deleterious archaic sequences also created large regions of the human genome that are significantly depleted of both Neanderthal and Denisovan ancestry. These deserts of archaic hominin sequences are interesting because they may help identify genetic changes that contribute to <a href="https://www.ncbi.nlm.nih.gov/books/NBK210023/">uniquely modern human traits</a>, such as our capacity for language, symbolic thought and culture, although there is debate about just <a href="https://doi.org/10.1098/rstb.2019.0424">how unique these traits are to modern humans</a>. </p>
<p>In contrast, there are also sequences inherited from Neanderthals and Denisovans that were advantageous, and helped modern humans adapt to new environments as they dispersed out of Africa. Neanderthal versions of several immune-related genes have risen to high frequency in several non-African populations, which likely <a href="https://www.quantamagazine.org/how-neanderthal-dna-helps-humanity-20160526/">helped humans fend off exposure to new pathogens</a>. Similarly, a version of the <em>EPAS1</em> gene, which contributes to <a href="https://www.nationalgeographic.com/science/article/sex-with-extinct-humans-passed-high-altitude-gene-to-tibetans">high-altitude adaptation</a> in Tibetan populations, was inherited from Denisovans.</p>
<p>It is also becoming clear that DNA sequences inherited from Neanderthal and Denisovan ancestors contribute to the burden of disease in present day individuals. Neanderthal sequences have been shown to <a href="https://doi.org/10.1038/s41586-020-2818-3">influence both susceptibility to</a> and <a href="https://doi.org/10.1073/pnas.2026309118">protection against severe COVID-19</a>. Archaic hominin sequences have also <a href="https://doi.org/10.1016/j.cub.2022.08.027">been shown to influence</a> susceptibility to depression, Type 2 diabetes and celiac disease among others. Ongoing studies will undoubtedly reveal more about how Neanderthal and Denisovan ancestry contributes to human disease.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/488685/original/file-20221007-17489-agxzvz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="photo of man holding a human skull and looking at the face" src="https://images.theconversation.com/files/488685/original/file-20221007-17489-agxzvz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488685/original/file-20221007-17489-agxzvz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488685/original/file-20221007-17489-agxzvz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488685/original/file-20221007-17489-agxzvz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488685/original/file-20221007-17489-agxzvz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488685/original/file-20221007-17489-agxzvz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488685/original/file-20221007-17489-agxzvz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Svante Pääbo’s work built the foundation of the new field of paleogenomics.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/svante-paabo-director-of-the-max-planck-institute-for-news-photo/1243699506">Jens Schluete via Getty Images News</a></span>
</figcaption>
</figure>
<p>I was a graduate student when the <a href="https://www.genome.gov/11006929/2003-release-international-consortium-completes-hgp">Human Genome Project</a> was nearing completion a little over two decades ago. I was drawn to genetics because I found it fascinating that, by analyzing the DNA of present-day individuals, you could learn aspects about a population’s history that occurred tens of thousands of years ago.</p>
<p>Today, I am just as fascinated by the stories contained in our DNA, and the work of Svante Pääbo and his colleagues has enabled these stories to be told in a way that simply was not possible before.</p><img src="https://counter.theconversation.com/content/191913/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joshua Akey receives funding from NIH. </span></em></p>
Ancient DNA helps reveal the tangled branches of the human family tree. Not only did our ancestors live alongside other human species, they mated with them, too.
Joshua Akey, Professor at the Lewis-Sigler Institute for Integrative Genomics, Princeton University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/191899
2022-10-04T23:15:56Z
2022-10-04T23:15:56Z
What’s next for ancient DNA studies after Nobel Prize honors groundbreaking field of paleogenomics
<figure><img src="https://images.theconversation.com/files/488157/original/file-20221004-14-rupej6.jpg?ixlib=rb-1.1.0&rect=360%2C291%2C4414%2C3088&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Researchers need to be careful not to contaminate ancient samples with their own DNA.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/female-scientist-filling-pipette-trays-at-fume-hood-royalty-free-image/1374565126">Caia Image via Getty Images</a></span></figcaption></figure><p>For the first time, a Nobel Prize recognized the field of anthropology, the study of humanity. Svante Pääbo, a pioneer in the study of ancient DNA, or aDNA, was awarded the 2022 <a href="https://www.nobelprize.org/prizes/medicine/2022/summary/">prize in physiology or medicine</a> for his breathtaking achievements sequencing DNA extracted from ancient skeletal remains and reconstructing early humans’ genomes – that is, all the genetic information contained in one organism.</p>
<p>His accomplishment was once only the stuff of Jurassic Park-style science fiction. But Pääbo and many colleagues, working in large multidisciplinary teams, <a href="https://theconversation.com/nobel-prize-svante-paabos-ancient-dna-discoveries-offer-clues-as-to-what-makes-us-human-191805">pieced together the genomes</a> of our distant cousins, the famous Neanderthals and the more elusive Denisovans, whose existence was not even known until their <a href="https://www.nytimes.com/2010/12/23/science/23ancestor.html">DNA was sequenced</a> from a tiny pinky bone of a child <a href="https://theconversation.com/fresh-clues-to-the-life-and-times-of-the-denisovans-a-little-known-ancient-group-of-humans-110504">buried in a cave in Siberia</a>. Thanks to interbreeding with <a href="https://theconversation.com/ancient-teenager-the-first-known-person-with-parents-of-two-different-species-101965">and among</a> these early humans, their genetic traces <a href="https://theconversation.com/neanderthals-died-out-40-000-years-ago-but-there-has-never-been-more-of-their-dna-on-earth-189021">live on in many of us today</a>, shaping our bodies and our disease vulnerabilities – for example, to <a href="https://doi.org/10.1073/pnas.2026309118">COVID-19</a>.</p>
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<p>The world has learned a startling amount about <a href="https://theconversation.com/six-recent-discoveries-that-have-changed-how-we-think-about-human-origins-190274">our human origins</a> in the last dozen years since Pääbo and teammates’ groundbreaking discoveries. And the field of paleogenomics has rapidly expanded. Scientists have now sequenced <a href="https://theconversation.com/we-sequenced-the-oldest-ever-dna-from-million-year-old-mammoths-155485">mammoths that lived a million years ago</a>. Ancient DNA has addressed questions ranging from the origins of the <a href="https://www.sapiens.org/archaeology/ancient-dna-native-americans/">first Americans</a> to the domestication of <a href="https://www.smithsonianmag.com/smart-news/genetic-sequencing-pinpoints-the-origins-of-the-domestic-horse-180978926/">horses</a> and <a href="https://bigthink.com/the-past/ancient-dogs/">dogs</a>, the spread of <a href="https://theconversation.com/ancient-dna-is-revealing-the-origins-of-livestock-herding-in-africa-114387">livestock herding</a> and our bodies’ adaptations – or lack thereof – to <a href="https://www.newscientist.com/article/2331213-evolution-of-lactose-tolerance-probably-driven-by-famine-and-disease/">drinking milk</a>. Ancient DNA can even shed light on <a href="https://doi.org/10.1073/pnas.2120786119">social questions</a> of marriage, kinship and mobility. Researchers can now sequence DNA not only from the remains of ancient humans, animals and plants, but even from their <a href="https://theconversation.com/digging-deep-dna-molecules-in-ancient-dirt-offer-a-treasure-trove-of-clues-to-our-past-172489">traces left in cave dirt</a>.</p>
<p>Alongside this growth in research, people have been grappling with <a href="https://theconversation.com/ancient-dna-unearths-fascinating-secrets-but-what-about-the-ethics-85186">concerns about the speed</a> with which skeletal collections around the world have been sampled for aDNA, leading to broader conversations about <a href="https://theconversation.com/rights-of-the-dead-and-the-living-clash-when-scientists-extract-dna-from-human-remains-94284">how research should be done</a>. Who should conduct it? Who may benefit from or be harmed by it, and who gives consent? And how can the field become more equitable? As an <a href="https://scholar.google.com/citations?user=3QKcZMoAAAAJ&hl=en&oi=ao">archaeologist</a> who partners with geneticists to study <a href="https://theconversation.com/ancient-dna-helps-reveal-social-changes-in-africa-50-000-years-ago-that-shaped-the-human-story-175436">ancient African history</a>, I see both challenges and opportunities ahead.</p>
<h2>Building a better discipline</h2>
<p>One positive sign: Interdisciplinary researchers are working to establish <a href="https://theconversation.com/why-scholars-have-created-global-guidelines-for-ancient-dna-research-169284">basic common guidelines</a> for research design and conduct.</p>
<p>In North America, scholars have worked to address inequities by designing programs that <a href="https://www.singconsortium.org/">train future generations of Indigenous geneticists</a>. These are now expanding to other historically underrepresented communities in the world. In museums, <a href="https://doi.org/10.1073/pnas.1822038116">best practices for sampling</a> are being put into place. They aim to minimize destruction to ancestral remains, while gleaning the most new information possible.</p>
<p><iframe id="ucxNW" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/ucxNW/4/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<p>But there is a long way to go to develop and enforce community consultation, ethical sampling and data sharing policies, especially in more resource-constrained parts of the world. The divide <a href="https://doi.org/10.3389/fgene.2022.880170">between the developing world and rich industrialized nations</a> is especially stark when looking at where <a href="https://www.google.com/maps/d/viewer?mid=1qwXOKV5uoQntgBsxQrxS01YHpbs&ll=-3.81666561775622e-14%2C6.726945455479381&z=1">ancient DNA labs</a>, funding and research publications are concentrated. It leaves fewer opportunities for scholars from parts of Asia, Africa and the Americas to be trained in the field and lead research. </p>
<p>The field faces structural challenges, such as the relative lack of funding for archaeology and cultural heritage protection in lower income countries, worsened by a <a href="https://theconversation.com/archaeology-is-changing-slowly-but-its-still-too-tied-up-in-colonial-practices-133243">long history of extractive research practices</a> and looming <a href="https://doi.org/10.1038/s41558-022-01280-1">climate change and site destruction</a>. These issues strengthen the regional bias in paleogenomics, which helps explain why some parts of the world – such as Europe – are so well-studied, while Africa – the <a href="https://theconversation.com/ancient-dna-increases-the-genetic-time-depth-of-modern-humans-84716">cradle of humankind</a> and the <a href="https://genomebiology.biomedcentral.com/articles/10.1186/s13059-019-1740-1">most genetically diverse continent</a> – is relatively understudied, with shortfalls in <a href="https://www.theguardian.com/commentisfree/2022/jan/03/africa-humanity-heritage-archaeologist">archaeology</a>, <a href="https://www.nature.com/articles/d44148-022-00051-6">genomics</a> and <a href="https://www.discovermagazine.com/planet-earth/with-ancient-human-dna-africas-deep-history-is-coming-to-light">ancient DNA</a>.</p>
<h2>Making public education a priority</h2>
<p>How paleogenomic findings are interpreted and communicated to the public <a href="https://www.nature.com/articles/s41559-019-0961-8">raises other concerns</a>. Consumers are regularly bombarded with advertisements for personal ancestry testing, <a href="https://blogs.ancestry.com/cm/goodbye-lederhosen-hello-kilt-how-a-dna-test-changed-one-mans-identity-forever/">implying that genetics and identity are synonymous</a>. But lived experiences and decades of scholarship show that biological ancestry and socially defined identities <a href="https://theconversation.com/genetic-ancestry-tests-dont-change-your-identity-but-you-might-98663">do not map so easily onto one another</a>.</p>
<p>I’d argue that scholars studying aDNA have a responsibility to work with educational institutions, like schools and museums, to communicate the meaning of their research to the public. This is particularly important because people with political agendas – <a href="https://www.smithsonianmag.com/history/when-ancient-dna-gets-politicized-180972639/">even elected officials</a> – <a href="https://theconversation.com/white-supremacists-believe-in-genetic-purity-science-shows-no-such-thing-exists-146763">try to manipulate findings</a>.</p>
<p>For example, white supremacists have <a href="https://www.nytimes.com/2018/10/19/us/white-supremacists-science-genetics.html">erroneously equated lactose tolerance with whiteness</a>. It’s a falsehood that would be laughable to many livestock herders from Africa, one of the multiple <a href="https://www.the-scientist.com/daily-news/origins-of-lactase-persistence-in-africa-37810">centers of origin</a> for genetic traits enabling people to digest milk.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/308159/original/file-20191221-11900-1i8iio9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308159/original/file-20191221-11900-1i8iio9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308159/original/file-20191221-11900-1i8iio9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=505&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308159/original/file-20191221-11900-1i8iio9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=505&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308159/original/file-20191221-11900-1i8iio9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=505&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308159/original/file-20191221-11900-1i8iio9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=635&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308159/original/file-20191221-11900-1i8iio9.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=635&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308159/original/file-20191221-11900-1i8iio9.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=635&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The 2010 excavation in the East Gallery of Denisova Cave, where the ancient hominin species known as the Denisovans was discovered.</span>
<span class="attribution"><span class="source">Bence Viola. Dept. of Anthropology, University of Toronto</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Leaning in at the interdisciplinary table</h2>
<p>Finally, there’s a discussion to be had about how <a href="https://theconversation.com/ancient-dna-is-a-powerful-tool-for-studying-the-past-when-archaeologists-and-geneticists-work-together-111127">specialists in different disciplines should work together</a>.</p>
<p>Ancient DNA research has grown rapidly, sometimes without sufficient conversations happening beyond the genetics labs. This oversight has provoked a <a href="https://www.nature.com/articles/d41586-018-03773-6">backlash</a> from archaeologists, anthropologists, historians and linguists. Their disciplines have generated decades or even centuries of research that shape ancient DNA interpretations, and their labor makes paleogenomic studies possible.</p>
<p>As an archaeologist, I see the aDNA “revolution” as usefully disrupting our practice. It prompts the archaeological community to reevaluate <a href="https://www.sapiens.org/archaeology/south-africa-repatriation/">where ancestral skeletal collections come from and should rest</a>. It challenges us to publish archaeological data that is sometimes only revealed for the first time in the supplements of paleogenomics papers. It urges us to grab a seat at the table and help drive projects from their inception. We can design research grounded in archaeological knowledge, and may have longer-term and stronger ties to museums and to local communities, whose partnership is key to doing research right.</p>
<p>If archaeologists embrace this moment that Pääbo’s Nobel Prize is spotlighting, and lean in to the sea changes rocking our field, it can change for the better.</p><img src="https://counter.theconversation.com/content/191899/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mary Prendergast does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Thousands of ancient genomes have been sequenced to date. A Nobel Prize highlights tremendous opportunities for aDNA, as well as challenges related to rapid growth, equity and misinformation.
Mary Prendergast, Associate Professor of Anthropology, Rice University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/187928
2022-09-28T20:59:05Z
2022-09-28T20:59:05Z
From fertiliser to phantom: DNA cracks a century-old mystery about New Zealand’s only extinct freshwater fish
<figure><img src="https://images.theconversation.com/files/478543/original/file-20220810-13286-jwchpp.jpeg?ixlib=rb-1.1.0&rect=120%2C74%2C3627%2C1589&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The upokororo, or New Zealand grayling (_Prototroctes oxyrhynchus_)</span> <span class="attribution"><span class="source">Te Papa CC BYNC-ND 4.0</span>, <span class="license">Author provided</span></span></figcaption></figure><p>In 1923, Te Rangi Hīroa (Sir Peter Buck) documented the <a href="https://www.nzgeo.com/stories/out-of-the-frying-pan-into-oblivion/">last confirmed capture</a> of a special fish – the upokororo or New Zealand grayling.</p>
<p>More than two decades later, the upokororo received full governmental protection, but it was too late. No further sightings were ever confirmed. In 1986, the upokororo was <a href="https://www.iucnredlist.org/species/18384/20887241">officially listed as extinct</a>.</p>
<p>The upokororo disappeared so quickly that it’s mostly unknown to Western science.
But almost a century after the last living upokororo was seen, we are now using ancient DNA to finally provide some answers. </p>
<p>Our <a href="https://academic.oup.com/zoolinnean/advance-article/doi/10.1093/zoolinnean/zlac077/6726151?login=false">research reveals</a> the upokororo’s ancient origins, going back 15 to 23 million years, and a link to its Australian cousins. </p>
<h2>From fertiliser to phantom</h2>
<p>Historical accounts show the upokororo was once very common in rivers across the country. In the 1800s, cartloads were caught and traded for use as fertiliser and food. </p>
<p>But then it disappeared, likely as a result of a combination of factors – pollution, overfishing, disease and predation by introduced trout.</p>
<figure class="align-center ">
<img alt="A historic image showing men catching fish." src="https://images.theconversation.com/files/478709/original/file-20220811-17-kjg38d.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478709/original/file-20220811-17-kjg38d.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=454&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478709/original/file-20220811-17-kjg38d.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=454&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478709/original/file-20220811-17-kjg38d.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=454&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478709/original/file-20220811-17-kjg38d.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=571&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478709/original/file-20220811-17-kjg38d.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=571&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478709/original/file-20220811-17-kjg38d.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=571&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A funnel-shaped net is set to capture upokororo in the Waiapu River.</span>
<span class="attribution"><span class="source">Alexander Turnball Library CC BY-NC 4.0</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Despite its abundance in the past, only a small handful of preserved upokororo still exist in museums today. This is one reason we know so little about this curious fish. </p>
<p>A second reason is that many of these specimens have been treated with formaldehyde, a chemical that preserves the form of the fish but plays havoc with their DNA.</p>
<h2>Fishy frontiers</h2>
<p>The DNA in specimens “fixed” with chemicals like formaldehyde gets broken up into small pieces and stuck together. Over time, the DNA becomes more and more damaged. </p>
<p>This is a big challenge for researchers who want to study species like the upokororo and a major reason why extinct fish are understudied compared to other extinct species.</p>
<figure class="align-center ">
<img alt="A formalin-fixed specimen fo a New Zealand grayling." src="https://images.theconversation.com/files/478706/original/file-20220811-14-u1lvb6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478706/original/file-20220811-14-u1lvb6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478706/original/file-20220811-14-u1lvb6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478706/original/file-20220811-14-u1lvb6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478706/original/file-20220811-14-u1lvb6.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478706/original/file-20220811-14-u1lvb6.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478706/original/file-20220811-14-u1lvb6.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=500&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An example of a formalin-fixed New Zealand grayling, caught in the Clutha River (1874).</span>
<span class="attribution"><span class="source">Otago Museum CC BY 4.0</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Fortunately, <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/1755-0998.13505">new methods</a> have recently been developed that help to isolate and analyse small damaged fragments of DNA. This means genetic analysis of many “wet preserved” specimens like those of the upokororo is now possible for the first time. </p>
<p>Such genetic information can provide new insights into the origin and identity of extinct species.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-did-ancient-moa-survive-the-ice-age-and-what-can-they-teach-us-about-modern-climate-change-183350">How did ancient moa survive the ice age – and what can they teach us about modern climate change?</a>
</strong>
</em>
</p>
<hr>
<h2>Whakapapa of the upokororo</h2>
<p>Based on the general appearance of the upokororo, scientists have usually considered it to be a close relative of the Australian grayling. The Australian grayling is part of a family of fish that includes Stokell’s smelt and the New Zealand smelt, which are both still found in rivers across Aotearoa.</p>
<p>New DNA data confirmed the Australian grayling is the closest living relative of the upokororo, but only a distant cousin at best. Genetic comparisons showed the common ancestor of the two species lived more than 15 million years ago. </p>
<p>An ancient origin for the upokororo agrees well with the discovery of <a href="https://bioone.org/journals/acta-palaeontologica-polonica/volume-57/issue-2/app.2010.0127/Fish-Remains-Mostly-Otoliths-from-the-Non-Marine-Early-Miocene/10.4202/app.2010.0127.full">fossil grayling ear bones</a> in lake sediments from Saint Bathans in Central Otago.</p>
<figure class="align-center ">
<img alt="Palaeontologists sieving for fossils in the Manuherikia River, near Saint Bathans." src="https://images.theconversation.com/files/478844/original/file-20220811-22635-5piny7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478844/original/file-20220811-22635-5piny7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=291&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478844/original/file-20220811-22635-5piny7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=291&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478844/original/file-20220811-22635-5piny7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=291&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478844/original/file-20220811-22635-5piny7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=366&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478844/original/file-20220811-22635-5piny7.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=366&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478844/original/file-20220811-22635-5piny7.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=366&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Palaeontologists sieving for fossils in the Manuherikia River, near Saint Bathans. Fossils from this location are between 16 and 19 million years old.</span>
<span class="attribution"><span class="source">Nicrawlence/Wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Genetic and fossil data together suggest the ancestors of the upokororo arrived in Aotearoa following the birth of the Alpine Fault. Before that time, present-day Aotearoa was mostly beneath the ocean, during the height of the Oligocene “<a href="https://www.tandfonline.com/doi/full/10.1080/00288306.2014.904387">drowning</a>” 27 to 22 million years ago. </p>
<p>While baby upokororo could live in salt water, adults needed brackish or fresh water. The emergence of Aotearoa from beneath the waves would have created new habitats for the upokororo.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/i-will-miss-them-if-they-are-gone-stingrays-are-underrated-sharks-we-dont-know-enough-about-186214">'I will miss them if they are gone': stingrays are underrated sharks we don't know enough about</a>
</strong>
</em>
</p>
<hr>
<h2>Back from the brink?</h2>
<p>Some scientists have previously put forward a controversial idea. Could the Australian grayling be released into rivers in New Zealand to fill the ecological gap left by the extinction of the upokororo? </p>
<p>That probably wouldn’t be a good plan. Millions of years of independent evolution mean the niches filled by the Australian grayling and upokororo were likely very different.</p>
<p>If we can’t replace the upokororo, is it possible that they’re still out there somewhere in a remote waterway, waiting to be re-discovered? It wouldn’t be unprecedented. Takahē were thought to be extinct before a small population was <a href="https://www.nzgeo.com/stories/takahe-the-bird-that-came-back-from-the-dead/">re-discovered in the Murchison Mountains in 1948</a>. </p>
<figure class="align-center ">
<img alt="An image of a river, overlain with fish." src="https://images.theconversation.com/files/478720/original/file-20220811-4172-eoa5ws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/478720/original/file-20220811-4172-eoa5ws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/478720/original/file-20220811-4172-eoa5ws.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/478720/original/file-20220811-4172-eoa5ws.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/478720/original/file-20220811-4172-eoa5ws.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/478720/original/file-20220811-4172-eoa5ws.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/478720/original/file-20220811-4172-eoa5ws.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Could the New Zealand grayling be hiding out in remote waterways, such as the West Coast’s Buller River?</span>
<span class="attribution"><span class="source">Peter James Quinn</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Genetic data provide a new tool in the search for survivors. Environmental DNA in water samples from remote catchments can now be compared routinely to known DNA from the upokororo. Perhaps one day this will lead to a positive match that indicates the location of survivors. </p>
<p>Fish populations are in sharp decline globally. Lessons learned from past extinctions, like that of the upokororo, can help us preserve fish species for future generations. Hopefully we can heed the lessons from the past.</p><img src="https://counter.theconversation.com/content/187928/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kieren Mitchell receives funding from the Royal Society of New Zealand Marsden Fund. </span></em></p><p class="fine-print"><em><span>Nic Rawlence receives funding from the Royal Society of New Zealand Marsden Fund. </span></em></p><p class="fine-print"><em><span>Lachie Scarsbrook does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Historical accounts show the upokororo was once common in rivers across the country. It’s now officially extinct, but is there a chance survivors could still be found in remote waterways?
Lachie Scarsbrook, DPhil Student, University of Oxford
Kieren Mitchell, Postdoctoral Fellow, Department of Zoology, University of Otago
Nic Rawlence, Senior Lecturer in Ancient DNA, University of Otago
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/187927
2022-08-24T21:18:30Z
2022-08-24T21:18:30Z
Empty mollusc shells hold the story of evolution, even for extinct species. Now we can decode it
<figure><img src="https://images.theconversation.com/files/480720/original/file-20220824-16-6h01pu.jpg?ixlib=rb-1.1.0&rect=373%2C67%2C5125%2C2579&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption"></span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>Most people have collected shells at the beach. Some have even started a shell collection. But few people realise these shells are a unique genetic resource that scientists are only beginning to tap into.</p>
<p>For over a decade it has been possible to extract and sequence <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/1755-0998.12679">ancient DNA from empty mollusc shells</a> up to <a href="https://www.frontiersin.org/articles/10.3389/fevo.2020.00037/full">tens of thousands of years old</a>. However, these techniques have so far proven very expensive and unreliable.</p>
<p>Our new <a href="https://onlinelibrary.wiley.com/doi/10.1111/1755-0998.13696">international research</a> represents a major advance towards doing so consistently and (relatively) cheaply. We employed these methods to better understand the evolutionary relationships between diverse populations of Aotearoa New Zealand’s smallest abalone/pāua species, <em>Haliotis virginea</em>. </p>
<figure class="align-center ">
<img alt="The author in the lab with some pāua shells." src="https://images.theconversation.com/files/480016/original/file-20220819-24-8jxot8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480016/original/file-20220819-24-8jxot8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480016/original/file-20220819-24-8jxot8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480016/original/file-20220819-24-8jxot8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480016/original/file-20220819-24-8jxot8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480016/original/file-20220819-24-8jxot8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480016/original/file-20220819-24-8jxot8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Newly developed techniques can unlock the genetic secrets of mollusc shells like New Zealand pāua.</span>
<span class="attribution"><span class="source">Guy Frederik/University of Otago</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Our results show the evolutionary history in this group was a lot more complicated than it appeared. Understanding how different populations are related to one another, and indeed what species they are, is critical in managing and conserving marine areas and resources.</p>
<p>Natural history collections across the world contain tens of millions of mollusc shells. Broader application of our methods would increase the proportion of samples in museum collections that can be used for genetic research by several orders of magnitude. Normally, only freshly collected and preserved tissues are used for genetic research.</p>
<p>We can now sequence DNA from thousands of mollusc species that have never been found alive, including those that went extinct recently, or those living in difficult-to-access places such as on deep-sea mountains. Such palaeogenetic studies of shells can reveal how <a href="https://phys.org/news/2021-02-dna-modern-ancient-fossil-tropical.html">species and populations have changed through time</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/new-zealand-should-celebrate-its-remarkable-prehistoric-past-with-national-fossil-emblems-have-your-say-184942">New Zealand should celebrate its remarkable prehistoric past with national fossil emblems – have your say!</a>
</strong>
</em>
</p>
<hr>
<h2>A rich and varied biological menagerie</h2>
<p>Molluscs are an extraordinarily diverse animal group that includes snails, clams and octopuses.</p>
<p>In New Zealand, culturally important kaimoana (seafood) species such as green-lipped mussels are farmed extensively and are worth <a href="https://www.mpi.govt.nz/dmsdocument/15895-The-Governments-Aquaculture-Strategy-to-2025">hundreds of millions of dollars to the economy</a>. </p>
<p>Molluscs can also be carnivorous, such as New Zealand’s giant, worm-eating <em>Powelliphanta</em> snails, many of which are <a href="https://www.doc.govt.nz/nature/native-animals/invertebrates/powelliphanta-snails/">critically endangered</a>. </p>
<figure class="align-center ">
<img alt="One of New Zealand's land snails, the critically endangered Powelliphanta hochstetteri." src="https://images.theconversation.com/files/480713/original/file-20220824-20-3i57gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480713/original/file-20220824-20-3i57gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=794&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480713/original/file-20220824-20-3i57gn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=794&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480713/original/file-20220824-20-3i57gn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=794&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480713/original/file-20220824-20-3i57gn.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=998&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480713/original/file-20220824-20-3i57gn.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=998&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480713/original/file-20220824-20-3i57gn.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=998&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Many of New Zealand’s giant land snails are critically endangered, including <em>Powelliphanta hochstetteri</em> from the top of the South Island.</span>
<span class="attribution"><span class="source">Kerry Walton/University of Otago</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Blue sea dragons drift in the open ocean and feed on dangerous bluebottle jellyfish. Some cone snails shoot poisoned darts to catch fish, and have been known to kill humans. Fortunately, those in New Zealand are unlikely to be deadly.</p>
<figure class="align-center ">
<img alt="Blue sea dragon - a shell-less sea slug that feeds on dangerous jellyfish." src="https://images.theconversation.com/files/480015/original/file-20220819-12-whcepg.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480015/original/file-20220819-12-whcepg.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480015/original/file-20220819-12-whcepg.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480015/original/file-20220819-12-whcepg.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480015/original/file-20220819-12-whcepg.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480015/original/file-20220819-12-whcepg.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480015/original/file-20220819-12-whcepg.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Blue sea dragon – a shell-less sea slug that feeds on dangerous jellyfish.</span>
<span class="attribution"><span class="source">Sylke Rohrlach/Wikipedia</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Molluscs can also be parasitic, living inside or attached to other marine species. Tropical vampire snails suck the blood of sharks while they sleep. </p>
<p>Scaly-foot snails secrete metal scales like a suit of armour. Other species rely on camouflage for protection. Carrier shells glue rocks and other shells onto their own shell to blend in on the seafloor. </p>
<figure class="align-center ">
<img alt="The New Zealand carrier shell - a species that covers itself with rocks and other shells for camouflage." src="https://images.theconversation.com/files/480049/original/file-20220819-22-2sko2b.JPG?ixlib=rb-1.1.0&rect=59%2C694%2C3934%2C3299&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480049/original/file-20220819-22-2sko2b.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480049/original/file-20220819-22-2sko2b.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480049/original/file-20220819-22-2sko2b.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480049/original/file-20220819-22-2sko2b.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480049/original/file-20220819-22-2sko2b.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480049/original/file-20220819-22-2sko2b.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The New Zealand carrier shell – a species that covers itself with rocks and other shells for camouflage.</span>
<span class="attribution"><span class="source">Kerry Walton/University of Otago</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Most molluscs are really small. Tiny, almost transparent snails, often less than a millimetre in size even when fully grown, live deep underground in aquifers and caves. Conversely, giants such as the colossal squid, which live in Antarctic waters, can exceed 500kg and would produce a calamari ring larger than a hula hoop.</p>
<h2>The living dead of natural history collections</h2>
<p>Some molluscs living today were born before Europeans arrived in New Zealand. Icelandic clams have been recorded as living for <a href="https://museum.wales/blog/2122/Meet-Ming-the-clam---the-oldest-animal-in-the-world/#:%7E:text=At%20507%20years%20of%20age,was%20still%20a%20record%20breaker">more than 500 years</a>. </p>
<p>However, death may not be the end of their story. Most mollusc species produce a robust shell that can persist in the environment for thousands of years. Molluscs are, accordingly, very well represented in the fossil record, and have significantly improved our understanding of biodiversity changes through time.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/micro-snails-we-scraped-from-sidewalk-cracks-help-unlock-details-of-ancient-earths-biological-evolution-112362">'Micro snails' we scraped from sidewalk cracks help unlock details of ancient earth's biological evolution</a>
</strong>
</em>
</p>
<hr>
<p>Amazingly, only half of New Zealand’s roughly <a href="https://niwa.co.nz/news/new-zealand-first-in-the-world-to-catalogue-all-its-species-through-all-of-time#:%7E:text=The%20New%20Zealand%20Inventory%20of,all%20environments%2C%20from%20the%20Cambrian">4,000 living mollusc species</a> have been seen or collected alive. This includes tiny <a href="https://www.doc.govt.nz/globalassets/documents/conservation/native-animals/invertebrates/land-snail-posters/land-snails-bay-of-plenty-high-res.pdf">tree-top-dwelling snails</a> that have been sieved out of leaf litter, or shells scooped out of sediments around the base of undersea mountains that are too rocky to sample directly. </p>
<p>A large proportion of the known mollusc species have yet to be given scientific names. </p>
<figure class="align-center ">
<img alt="Shells of pāua (abalone)" src="https://images.theconversation.com/files/480018/original/file-20220819-24-mgps0e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/480018/original/file-20220819-24-mgps0e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=597&fit=crop&dpr=1 600w, https://images.theconversation.com/files/480018/original/file-20220819-24-mgps0e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=597&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/480018/original/file-20220819-24-mgps0e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=597&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/480018/original/file-20220819-24-mgps0e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=750&fit=crop&dpr=1 754w, https://images.theconversation.com/files/480018/original/file-20220819-24-mgps0e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=750&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/480018/original/file-20220819-24-mgps0e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=750&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Virgin pāua live in subtidal habitats all around New Zealand, including on isolated islands, which makes sampling difficult.</span>
<span class="attribution"><span class="source">Kerry Walton/University of Otago</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Natural history collections represent an invaluable and undervalued resource: an archive of knowledge and the solutions to questions never before thought possible, or that were held back by technological limitations of the time.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/museum-specimens-could-help-fight-the-next-pandemic-why-preserving-collections-is-crucial-to-future-scientific-discoveries-148293">Museum specimens could help fight the next pandemic – why preserving collections is crucial to future scientific discoveries</a>
</strong>
</em>
</p>
<hr>
<p>With congruent climate and biodiversity crises, museum collections are no mere Victorian-era flights of fancy. They are critical to help us to better understand and protect our unique fauna and flora. These collections are essential to connect present and future generations with these amazing species.</p><img src="https://counter.theconversation.com/content/187927/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nic Rawlence receives funding from the Royal Society of New Zealand Marsden Fund. </span></em></p><p class="fine-print"><em><span>Kerry Walton does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Only half of New Zealand’s roughly 4,000 mollusc species have been seen alive. Now geneticists can decode DNA from shells in museum collections to trace the life histories of extinct or rare species.
Kerry Walton, Researcher, University of Otago
Nic Rawlence, Senior Lecturer in Ancient DNA, University of Otago
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/183350
2022-05-26T01:04:28Z
2022-05-26T01:04:28Z
How did ancient moa survive the ice age – and what can they teach us about modern climate change?
<figure><img src="https://images.theconversation.com/files/464368/original/file-20220519-13-9kmnqm.jpg?ixlib=rb-1.1.0&rect=26%2C188%2C744%2C773&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Artist's impression of an eastern moa in its podocarp forest habitat. Paul Martinson.</span> <span class="attribution"><a class="source" href="https://collections.tepapa.govt.nz/object/710922">Te Papa Tongarewa/Museum of NZ</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>One species of iconic moa was almost wiped out during the last ice age, according to <a href="https://doi.org/10.1098/rsbl.2022.0013">recently published research</a>. But a small population survived in a modest patch of forest at the bottom of New Zealand’s South Island, and rapidly spread back up its east coast once the climate began to warm.</p>
<p>What we’re learning about this remarkable survival story has implications for the way we can help living species adapt to climate change, and how we conserve and restore what may be important future habitats.</p>
<p>Growing to around 80kg and up to 1.8 metres tall, the <a href="https://nzbirdsonline.org.nz/species/eastern-moa">eastern moa</a> was one of the smaller of the nine extinct moa species. It got its name because its fossil bones have been found in sand dunes, swamps, caves and middens all along the eastern parts of the South Island – Southland, Otago, Canterbury and Marlborough.</p>
<p>Eastern moa became extinct from over-hunting and habitat destruction by humans, and <a href="https://www.frontiersin.org/articles/10.3389/fevo.2021.757988/full">possibly predation</a> by kurī (dogs) and kiore (rats). But were eastern moa populations thriving when people arrived, or were they already in trouble due to ancient climate change? </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/464132/original/file-20220519-20-t0w2ie.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464132/original/file-20220519-20-t0w2ie.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464132/original/file-20220519-20-t0w2ie.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464132/original/file-20220519-20-t0w2ie.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464132/original/file-20220519-20-t0w2ie.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464132/original/file-20220519-20-t0w2ie.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464132/original/file-20220519-20-t0w2ie.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Skull of an eastern moa. Genetic information can be obtained from moa bones even after thousands of years. Te Papa CC BY-NC-ND 4.0.</span>
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</figure>
<h2>Refuge in the south</h2>
<p>Between 29,000 and 19,000 years ago, New Zealand was in the grip of an ice age. Glaciers were much larger and more widespread than they are today, and the distribution of grasslands and forests changed as the climate became colder and drier.</p>
<p>Current climate change threatens the survival of many different species, and the same was true of climate change thousands of years ago. The fossil record hints that the ice age was bad news for eastern moa, as few eastern moa bones from this period have been discovered. </p>
<p>But a lack of fossils doesn’t necessarily mean a species was doing it tough. Perhaps they just avoided the caves and swamps where we might eventually discover their bones.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-a-change-in-climate-wiped-out-the-siberian-unicorn-107365">How a change in climate wiped out the 'Siberian unicorn'</a>
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</em>
</p>
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<p>To find out more, we sequenced DNA from dozens of eastern moa bones to see how their genetic diversity and population size changed over the past 30,000 years.</p>
<p>Large and healthy animal populations tend to have high genetic diversity, while low genetic diversity can be a sign that a population is in decline. We found eastern moa had very low genetic diversity immediately after the last ice age.</p>
<p>So eastern moa didn’t cope well with the ice age climate – but how did they manage to escape extinction? Our study provides a clue: their genetic diversity was highest in the very south of the South Island. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/464370/original/file-20220519-20-ftww5u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/464370/original/file-20220519-20-ftww5u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/464370/original/file-20220519-20-ftww5u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/464370/original/file-20220519-20-ftww5u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/464370/original/file-20220519-20-ftww5u.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/464370/original/file-20220519-20-ftww5u.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/464370/original/file-20220519-20-ftww5u.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Rimu were prominent in the podocarp forests that eastern moa preferred. The distribution of these forests changed dramatically during the ice age.</span>
<span class="attribution"><span class="source">Katja Schulz/Flickr CC-BY 2.0</span></span>
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<h2>Preserving future habitats</h2>
<p>During the ice age, grassland replaced wet podocarp forests in many areas. Those forests were the favourite habitat of eastern moa, possibly explaining why they struggled to survive. </p>
<p>Luckily for eastern moa, however, <a href="https://sciblogs.co.nz/lost-worlds/2021/03/17/climate-refugee-or-hardy-local-solving-a-botanical-mystery/">small pockets of forest survived</a> in southern New Zealand during this time. While eastern moa disappeared from most of the country, our study suggests they clung on in remnant forest at the very south of the South Island. </p>
<p>Scientists have a special name for pockets of habitat where species can shelter and endure climate change – “refugia”. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-the-warming-world-could-turn-many-plants-and-animals-into-climate-refugees-72722">How the warming world could turn many plants and animals into climate refugees</a>
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<p>Once the climate began to return to pre-ice age conditions, eastern moa were able to return to parts of the country they had formerly occupied. They bounced back so well that they were the most common moa in some parts of New Zealand at the time of Polynesian arrival.</p>
<p>Ancient DNA from fossils across the world has shown that refugia play an important role in allowing species to adapt to climate change. The story of eastern moa shows this is equally true in New Zealand. </p>
<p>Importantly, though, the eastern moa was affected differently to other moa, showing not all species are affected by climate change in the same way. Our study emphasises the need to conserve and restore a diverse range of habitats for the future, given the places where species are found today may be unsuitable for them in the very near future. </p>
<p>By ensuring that species can continue to find appropriate refugia, we may reduce the number that become extinct as a result of our global impacts on the climate.</p><img src="https://counter.theconversation.com/content/183350/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nic Rawlence receives funding from the Royal Society of New Zealand Marsden Fund. </span></em></p><p class="fine-print"><em><span>Kieren Mitchell receives funding from the Royal Society of New Zealand Marsden Fund. </span></em></p><p class="fine-print"><em><span>Alexander Verry does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
DNA from ancient eastern moa bones is unlocking the secrets of their survival during the last ice age, and providing lessons for today’s threatened species.
Nic Rawlence, Senior Lecturer in Ancient DNA, University of Otago
Alexander Verry, Postdoctoral Researcher, Université de Toulouse III – Paul Sabatier
Kieren Mitchell, Postdoctoral Fellow, Department of Zoology, University of Otago
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/180327
2022-04-11T03:20:27Z
2022-04-11T03:20:27Z
A new method of extracting ancient DNA from tiny bones reveals the hidden evolutionary history of New Zealand geckos
<figure><img src="https://images.theconversation.com/files/455919/original/file-20220403-14-orpbvi.jpeg?ixlib=rb-1.1.0&rect=8%2C21%2C2894%2C1867&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Wikimedia Commons/Jennifer Moore</span></span></figcaption></figure><p>Aoteaora New Zealand has experienced a dynamic geological and climatic history. There was the separation from the southern super-continent Gondwana, the near drowning during the Oligocene some 27-22 million years ago, and the dramatic changes wrought by ice ages during the Pleistocene which started 2.6 million years ago.</p>
<p>In concert with these landscape-scale changes, the biodiversity of Aotearoa has undergone an equally dramatic journey, evolving into something uniquely New Zealand. Jared Diamond famously described our wildlife as “the nearest thing to studying life on another planet”.</p>
<p>The <a href="https://www.frontiersin.org/articles/10.3389/fevo.2021.757988/full">arrival of humans</a> from the late 13th century seriously hampered our ability to study this evolutionary history. It resulted in the extinction of around 70 birds, one mammal, a fish, up to three frogs and potentially a skink. Those that survived suffered severe range contractions and significant loss of genetic diversity. </p>
<p>Ancient DNA preserved in bones for tens of thousands of years has allowed scientists to unlock the genetic secrets of some of our taonga species and show how they responded to environmental change. </p>
<p>But most palaeogenetic research has focused on big flashy animals, like <a href="https://www.sciencedirect.com/science/article/pii/S0940960211000823">moa</a> and <a href="https://onlinelibrary.wiley.com/doi/full/10.1111/mec.13726">sea lions</a>, whose bones can sustain having small chunks chopped out without erasing the landmarks we use to distinguish species, such as a <a href="https://nzbirdsonline.org.nz/species/heavy-footed-moa">heavy-footed moa</a> from a <a href="https://nzbirdsonline.org.nz/species/south-island-giant-moa">giant moa</a>. Smaller animals were often ignored because sampling would have destroyed the whole bone, leaving only an angry museum curator to deal with.</p>
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<strong>
Read more:
<a href="https://theconversation.com/ancient-dna-suggests-woolly-mammoths-roamed-the-earth-more-recently-than-previously-thought-146073">Ancient DNA suggests woolly mammoths roamed the Earth more recently than previously thought</a>
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<p>What if there was a way to extract ancient DNA from these small bones, or taonga tūturu (cultural artefacts), without destroying the very specimen you are interested in? We have developed a technique that <a href="https://onlinelibrary.wiley.com/doi/10.1111/mec.16434">does just that</a> – an enzymatic bone bath that soaks out ancient DNA, allowing us to sequence ancient genomes without any observable bone damage. </p>
<h2>A dynamic biological heritage</h2>
<p>The upshot of our work is we can now reconstruct the previously hidden evolutionary histories of these small and neglected animals. </p>
<p>Take <a href="https://www.doc.govt.nz/nature/native-animals/reptiles-and-frogs/lizards/geckos/">New Zealand’s geckos</a> for example. There are at least 48 species, all of which have been severely impacted by human arrival, masking their true evolutionary history.</p>
<figure class="align-right ">
<img alt="A bag of gecko bones." src="https://images.theconversation.com/files/455916/original/file-20220403-53031-c6t30g.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/455916/original/file-20220403-53031-c6t30g.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/455916/original/file-20220403-53031-c6t30g.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/455916/original/file-20220403-53031-c6t30g.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/455916/original/file-20220403-53031-c6t30g.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/455916/original/file-20220403-53031-c6t30g.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/455916/original/file-20220403-53031-c6t30g.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Gecko bones were grouped by size, which was once thought to be the main taxonomic marker.</span>
<span class="attribution"><span class="source">Lachie Scarsbrook</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>It was previously thought you could only distinguish gecko species <a href="https://www.tandfonline.com/doi/pdf/10.1080/03014223.1998.9517573">based on their size</a>, not shape, to the point that pre-human gecko bones were separated into coarse quasi-taxonomic size bins. Considering most living New Zealand geckos show considerable overlap in size, this doesn’t help in discriminating between species.</p>
<p>Using <a href="https://bmcecolevol.biomedcentral.com/articles/10.1186/s12862-021-01808-7">3D scanning</a> and our new <a href="https://onlinelibrary.wiley.com/doi/10.1111/mec.16434">non-destructive extraction method</a>, we focused on the largest size class of gecko bones. It turns out you can distinguish gecko bones by shape but not size (with the exception of the largest extant species), which means our knowledge of Aotearoa’s geckos is now a palaeontological “blank slate”, a rare thing indeed. </p>
<p><a href="https://bmcecolevol.biomedcentral.com/articles/10.1186/s12862-021-01808-7">3D scanning</a> showed the bones from the largest size class either represented a previously unknown extinct gecko or <a href="https://www.reptiles.org.nz/herpetofauna/native/hoplodactylus-duvaucelii">Duvaucel’s gecko</a> (<em>Hoplodactylus duvauceli</em>) had undergone a large decline in morphological diversity as it was exiled from mainland New Zealand after human arrival.</p>
<figure class="align-center ">
<img alt="The skull of a gecko." src="https://images.theconversation.com/files/455918/original/file-20220403-23-qv3ee5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/455918/original/file-20220403-23-qv3ee5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=337&fit=crop&dpr=1 600w, https://images.theconversation.com/files/455918/original/file-20220403-23-qv3ee5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=337&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/455918/original/file-20220403-23-qv3ee5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=337&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/455918/original/file-20220403-23-qv3ee5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/455918/original/file-20220403-23-qv3ee5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/455918/original/file-20220403-23-qv3ee5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">3D scanning revealed gecko bones can be distinguished by shape but not size.</span>
<span class="attribution"><span class="source">Lachie Scarsbrook</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Our <a href="https://onlinelibrary.wiley.com/doi/10.1111/mec.16434">genetic analysis</a> of ancient mitochondrial genomes showed that Duvaucel’s gecko had undergone a major morphological and genetic bottleneck associated with mainland extinction. Not only that – it had a dynamic evolutionary history stretching back through time in response to some of the biggest changes in New Zealand’s geological and climatic past.</p>
<p>North and South Island populations diverged about five million years ago, as Duvaucel’s gecko dispersed across Pliocene straits and ephemeral islands that separated the two main islands of New Zealand long before Cook Strait formed some 500,000 years ago. These populations have now diverged so much that we think they could be different species, though more work remains to support our hunch.</p>
<figure class="align-center ">
<img alt="Lachie Scarsbrook with a Duvaucel's gecko (_Hoplodactylus duvauceli_)." src="https://images.theconversation.com/files/455917/original/file-20220403-11-zdqvgr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/455917/original/file-20220403-11-zdqvgr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/455917/original/file-20220403-11-zdqvgr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/455917/original/file-20220403-11-zdqvgr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/455917/original/file-20220403-11-zdqvgr.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/455917/original/file-20220403-11-zdqvgr.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/455917/original/file-20220403-11-zdqvgr.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Lachie Scarsbrook with a Duvaucel’s gecko (<em>Hoplodactylus duvauceli</em>).</span>
<span class="attribution"><span class="source">Lachie Scarsbrook</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>On the South Island, the ice ages forced Duvaucel’s gecko (and its <a href="https://www.tandfonline.com/doi/pdf/10.1080/0028825X.2020.1791915?casa_token=JkLYJDnZUR4AAAAA:2fk-5IltuxVzdcEw--6jtHceqXHIyxXdF3yshQLnKNiue1F4yIuFh8JyM0J3E0rT18FlUD-tfhHkeNU">forest home</a>) to retreat into separate northern and southern refugia during cold glacial periods, highlighting that glaciation can be a <a href="https://www.sciencedirect.com/science/article/abs/pii/S0169534716301367">creative force for biodiversity</a>. As sea levels rose, several populations were isolated on craggy islands in Cook Strait. While these island populations survived the arrival of humans, those on the mainland weren’t so lucky.</p>
<p>In the North Island it was a tale of two different worlds. Ancient lineages lived in remote and rugged areas like Waitomo, Northland and on geologically old islands like the Poor Knights and Great Barrier. In contrast, younger lineages became restricted to offshore islands as sea levels rose at the end of the last ice age some 11,000 years ago. Like their South Island cousins, isolated island lineages are today’s sole survivors.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/the-frog-and-the-gecko-why-tropical-species-are-at-greater-climate-risk-176003">The frog and the gecko: why tropical species are at greater climate risk</a>
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</p>
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<p>Far from being neglected, our small vertebrate fauna is finally coming of age as new scientific techniques are developed to reconstruct their biological heritage, and in turn, help evidence-based conservation management. </p>
<p>Further exciting discoveries are no doubt around the corner with new projects our lab group is conducting on geckos, <a href="https://www.doc.govt.nz/nature/native-animals/reptiles-and-frogs/lizards/skinks/">skinks</a> (they are plagued by <a href="https://www.tandfonline.com/doi/pdf/10.1080/03036758.1991.10420831">sized-based</a> identifications, too), <a href="https://academic.oup.com/zoolinnean/article/183/2/431/4685926">frogs</a> and tuatara. Sometimes the smallest things can unlock the biggest secrets.</p><img src="https://counter.theconversation.com/content/180327/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nic Rawlence receives funding from the Royal Society of New Zealand, and the Department of Conservation. </span></em></p><p class="fine-print"><em><span>Lachie Scarsbrook does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
Biologists have used ancient DNA, preserved in fossil bones for millennia, to study the evolution of large species, but now they can employ it to study small animals like lizards and frogs.
Nic Rawlence, Lecturer in Ancient DNA, University of Otago
Lachie Scarsbrook, DPhil Student in Archaeological Science, University of Oxford
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/175436
2022-02-23T16:03:13Z
2022-02-23T16:03:13Z
Ancient DNA helps reveal social changes in Africa 50,000 years ago that shaped the human story
<figure><img src="https://images.theconversation.com/files/446822/original/file-20220216-3870-1o2qb6l.jpg?ixlib=rb-1.1.0&rect=186%2C0%2C3661%2C2475&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Together with artifacts from the past, ancient DNA can fill in details about our ancient ancestors.</span> <span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Kondoa_Irangi_Rock_Paintings_(51507918388).jpg">Nina R/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Every person alive on the planet today is descended from people who lived as hunter-gatherers in Africa. </p>
<p>The continent is the cradle of <a href="https://theconversation.com/how-a-handful-of-prehistoric-geniuses-launched-humanitys-technological-revolution-171511">human origins and ingenuity</a>, and <a href="https://theconversation.com/archaeological-discoveries-are-happening-faster-than-ever-before-helping-refine-the-human-story-128743">with each new fossil and archaeological discovery</a>, we learn more about our shared African past. Such research tends to focus on when our species, <em>Homo sapiens</em>, <a href="https://www.scientificamerican.com/article/how-homo-sapiens-became-the-ultimate-invasive-species/">spread out to other landmasses 80,000-60,000 years ago</a>. But what happened in Africa after that, and why don’t we know more about the people who remained?</p>
<p>Our 2022 study, conducted by an interdisciplinary team of 44 researchers based in 12 countries, <a href="https://www.nature.com/articles/s41586-022-04430-9">helps answer these questions</a>. By sequencing and analyzing ancient DNA (aDNA) from people who lived as long ago as 18,000 years, we roughly doubled the age of sequenced aDNA from sub-Saharan Africa. And this genetic information helps <a href="https://scholar.google.com/citations?user=GlrnQDgAAAAJ&hl=en&oi=ao">anthropologists</a> <a href="https://scholar.google.com/citations?user=MQkcYDYAAAAJ&hl=en&oi=ao">like</a> <a href="https://scholar.google.com/citations?user=3QKcZMoAAAAJ&hl=en&oi=ao">us</a> understand more about how modern humans were moving and mingling in Africa long ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/441914/original/file-20220121-8326-sxvlib.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="View from above of archaeological excavation" src="https://images.theconversation.com/files/441914/original/file-20220121-8326-sxvlib.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441914/original/file-20220121-8326-sxvlib.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441914/original/file-20220121-8326-sxvlib.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441914/original/file-20220121-8326-sxvlib.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441914/original/file-20220121-8326-sxvlib.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441914/original/file-20220121-8326-sxvlib.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441914/original/file-20220121-8326-sxvlib.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">People took shelter in natural rock overhangs, leaving behind an archaeological record of their daily activities – and sometimes their graves. By digging carefully, archaeologists can connect information from aDNA to information about the social lives of these people.</span>
<span class="attribution"><span class="source">Jacob Davis</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>Tracing our human past in Africa</h2>
<p><a href="https://theconversation.com/new-moroccan-fossils-suggest-humans-lived-and-evolved-across-africa-100-000-years-earlier-than-we-thought-78826">Beginning about 300,000 years ago</a>, people in Africa who looked like us – the earliest anatomically modern humans – also started behaving in ways that seem very human. They made <a href="https://www.smithsonianmag.com/science-nature/how-drastic-ecological-change-led-leap-forward-behavior-weapons-and-tools-180976101/">new kinds of stone tools and began transporting raw materials</a> up to 250 miles (400 kilometers), likely through trade networks. By 140,000-120,000 years ago, people made <a href="https://scitechdaily.com/early-humans-used-bone-tools-to-produce-clothing-in-morocco-120000-years-ago/">clothing from animal skins</a> and began to <a href="https://www.smithsonianmag.com/smart-news/worlds-oldest-jewelry-discovered-in-moroccan-cave-180978766/">decorate themselves with pierced marine shell beads</a>. </p>
<p>While early innovations appeared in a patchwork fashion, a more widespread shift happened around 50,000 years ago – around the same time that people started <a href="https://www.nationalgeographic.com/history/article/australia-aboriginal-early-human-evolution-spd">moving into places as distant as Australia</a>. New types of stone and bone tools became common, and people began <a href="https://theconversation.com/the-tiny-ostrich-eggshell-beads-that-tell-the-story-of-africas-past-128577">fashioning and exchanging ostrich eggshell beads</a>. And while most <a href="https://theconversation.com/an-ancient-san-rock-art-mural-in-south-africa-reveals-new-meaning-157177">rock art in Africa</a> is undated and badly weathered, an increase in <a href="https://theconversation.com/what-the-use-of-ochre-tells-us-about-the-capabilities-of-our-african-ancestry-47081">ochre pigment at archaeological sites</a> hints at an explosion of art. </p>
<p>What caused this shift, known as the <a href="https://en.wikipedia.org/wiki/Late_Stone_Age">Later Stone Age</a> transition, has been a longstanding archaeological mystery. Why would certain tools and behaviors, which up until that point had appeared in a piecemeal way across Africa, suddenly become widespread? Did it have something to do with changes in the number of people, or how they interacted? </p>
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<a href="https://images.theconversation.com/files/441913/original/file-20220121-9541-bx79fs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Nine disc-shaped beads" src="https://images.theconversation.com/files/441913/original/file-20220121-9541-bx79fs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/441913/original/file-20220121-9541-bx79fs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=474&fit=crop&dpr=1 600w, https://images.theconversation.com/files/441913/original/file-20220121-9541-bx79fs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=474&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/441913/original/file-20220121-9541-bx79fs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=474&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/441913/original/file-20220121-9541-bx79fs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=596&fit=crop&dpr=1 754w, https://images.theconversation.com/files/441913/original/file-20220121-9541-bx79fs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=596&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/441913/original/file-20220121-9541-bx79fs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=596&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Beads made from ostrich eggshell were hot trade items and can show the extent of ancient social networks.</span>
<span class="attribution"><span class="source">Jennifer Miller</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>The challenge of accessing the deep past</h2>
<p>Archaeologists reconstruct human behavior in the past mainly through things people left behind – remains of their meals, tools, ornaments and <a href="https://theconversation.com/how-we-discovered-the-oldest-human-burial-in-africa-and-what-it-tells-us-about-our-ancestors-160122">sometimes even their bodies</a>. These records may accumulate over thousands of years, creating views of daily livelihoods that are really averages over long periods of time. However, it’s hard to study ancient demography, or how populations changed, from the archaeological record alone. </p>
<p>This is where DNA can help. When combined with evidence from archaeology, linguistics and oral and written history, scientists can piece together how people moved and interacted based on which groups share genetic similarities.</p>
<p>But DNA from living people can’t tell the whole story. African populations have been transformed over the past 5,000 years by the <a href="https://theconversation.com/ancient-dna-is-revealing-the-origins-of-livestock-herding-in-africa-114387">spread of herding and farming</a>, the <a href="https://theconversation.com/how-we-recreated-a-lost-african-city-with-laser-technology-92852">development of cities</a>, <a href="https://theconversation.com/archaeology-shows-how-ancient-african-societies-managed-pandemics-138217">ancient pandemics</a> and the ravages of <a href="https://theconversation.com/a-digital-archive-of-slave-voyages-details-the-largest-forced-migration-in-history-74902">colonialism and slavery</a>. These processes caused <a href="https://www.nytimes.com/2020/02/12/science/west-africa-ancient-humans.html">some lineages to vanish</a> and <a href="https://theconversation.com/mitochondrial-dna-reveals-unexpected-ancestral-connections-122053">brought others together</a>, forming new populations. </p>
<p>Using present-day DNA to reconstruct ancient genetic landscapes is like reading a letter that was left out in the rain: some words are there but blurred, and some are gone completely. Researchers need ancient DNA from archaeological human remains to explore human diversity in different places and times and to understand what factors shaped it.</p>
<p>Unfortunately, aDNA from Africa is particularly hard to recover because the continent straddles the equator and heat and humidity degrade DNA. While the <a href="https://www.scientificamerican.com/article/oldest-ancient-human-dna-details-dawn-of-neandertals/">oldest aDNA from Eurasia is roughly 400,000 years old</a>, all sequences from sub-Saharan Africa to date have been younger than around 9,000 years. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/444879/original/file-20220207-47158-11n9ym1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Map with markers showing distribution of ancient DNA data in Africa, and the world." src="https://images.theconversation.com/files/444879/original/file-20220207-47158-11n9ym1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444879/original/file-20220207-47158-11n9ym1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=625&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444879/original/file-20220207-47158-11n9ym1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=625&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444879/original/file-20220207-47158-11n9ym1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=625&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444879/original/file-20220207-47158-11n9ym1.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=785&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444879/original/file-20220207-47158-11n9ym1.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=785&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444879/original/file-20220207-47158-11n9ym1.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=785&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Map of all published ancient genomes, with black dots scaled to the number of individuals’ genomes. Blue dots indicate Later Stone Age foragers comparable to those in our study. Red stars indicate individuals reported for the first time in our study. Inset map underscores the gap between Africa and other parts of the world in terms of published ancient genomes. Ancient DNA preserved between the Tropics of Cancer and Capricorn is rare.</span>
<span class="attribution"><span class="source">Mary Prendergast; basemaps by Natural Earth</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Breaking the ‘tropical ceiling’</h2>
<p>Because each person carries genetic legacies inherited from generations of their ancestors, our team was able to use DNA from individuals who lived between 18,000-400 years ago to explore how people interacted as far back as the last 80,000-50,000 years. This allowed us, for the first time, to test whether demographic change played a role in the Later Stone Age transition. </p>
<p><a href="https://www.nature.com/articles/s41586-022-04430-9">Our team sequenced aDNA</a> from six individuals buried in what are now Tanzania, Malawi and Zambia. We compared these sequences to previously studied aDNA from 28 individuals buried at sites stretching from Cameroon to Ethiopia and down to South Africa. We also generated new and improved DNA data for 15 of these people, trying to extract as much information as possible from the small handful of ancient African individuals whose DNA is preserved well enough to study.</p>
<p>This created the largest genetic dataset so far for studying the population history of ancient African foragers – people who hunted, gathered or fished. We used it to explore population structures that existed prior to the sweeping changes of the past few thousand years.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/444614/original/file-20220205-23-d1055k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Museum building, palm trees" src="https://images.theconversation.com/files/444614/original/file-20220205-23-d1055k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/444614/original/file-20220205-23-d1055k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/444614/original/file-20220205-23-d1055k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/444614/original/file-20220205-23-d1055k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/444614/original/file-20220205-23-d1055k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/444614/original/file-20220205-23-d1055k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/444614/original/file-20220205-23-d1055k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">National Museum of Tanzania in Dar es Salaam. Ancient DNA studies in Africa are made possible by the efforts of curators to protect and preserve remains in tropical conditions.</span>
<span class="attribution"><span class="source">Mary Prendergast</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>DNA weighs in on a longstanding debate</h2>
<p>We found that people did in fact change how they moved and interacted around the Later Stone Age transition.</p>
<p>Despite being separated by thousands of miles and years, all the ancient individuals in this study were descended from the same three populations related to ancient and present-day eastern, southern and central Africans. The presence of eastern African ancestry as far south as Zambia, and southern African ancestry as far north as Kenya, indicates that people were moving long distances and having children with people located far away from where they were born. The only way this population structure could have emerged is if people were moving long distances over many millennia. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/446008/original/file-20220211-21-gafkub.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Lush African landscape" src="https://images.theconversation.com/files/446008/original/file-20220211-21-gafkub.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446008/original/file-20220211-21-gafkub.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446008/original/file-20220211-21-gafkub.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446008/original/file-20220211-21-gafkub.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446008/original/file-20220211-21-gafkub.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446008/original/file-20220211-21-gafkub.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446008/original/file-20220211-21-gafkub.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Genetic data now suggests that people moved and mingled across the eastern African Rift Valley during the Ice Ages.</span>
<span class="attribution"><span class="source">Elizabeth Sawchuk</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Additionally, our research showed that almost all ancient eastern Africans shared an unexpectedly high number of genetic variations with hunter-gatherers who today live in central African rainforests, making ancient eastern Africa truly a genetic melting pot. We could tell that this mixing and moving happened after about 50,000 years ago, when there was a major split in central African forager populations.</p>
<p>We also noted that the individuals in our study were genetically most like only their closest geographic neighbors. This tells us that after around 20,000 years ago, the foragers in some African regions were almost exclusively finding their partners locally. This practice must have been extremely strong and persisted for a very long time, as our results show that some groups remained genetically independent of their neighbors over several thousand years. It was especially clear in Malawi and Zambia, where the only close relationships we detected were between people buried around the same time at the same sites. </p>
<p>We don’t know why people began “living locally” again. Changing environments as the last Ice Age peaked and waned between about 26,000-11,500 years ago may have made it more economical to forage closer to home, or perhaps elaborate exchange networks reduced the need for people to travel with objects.</p>
<p>Alternatively, new group identities may have emerged, restructuring marriage rules. If so, we would expect to see artifacts and other traditions like rock art diversify, with specific types clumped into different regions. Indeed, <a href="https://www.theguardian.com/science/2022/jan/16/trail-of-african-bling-reveals-50000-year-old-social-network">this is exactly what archaeologists find</a> – a trend known as regionalization. Now we know that this phenomenon not only affected cultural traditions, but also the flow of genes. </p>
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<a href="https://images.theconversation.com/files/446872/original/file-20220216-20-cuzc12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="workers at a table sort tiny items by hand" src="https://images.theconversation.com/files/446872/original/file-20220216-20-cuzc12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/446872/original/file-20220216-20-cuzc12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/446872/original/file-20220216-20-cuzc12.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/446872/original/file-20220216-20-cuzc12.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/446872/original/file-20220216-20-cuzc12.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/446872/original/file-20220216-20-cuzc12.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/446872/original/file-20220216-20-cuzc12.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Recovering and sorting archaeological remains is a slow and laborious process, where even small fragments can tell big stories.</span>
<span class="attribution"><span class="source">Chelsea Smith</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<h2>New data, new questions</h2>
<p>As always, <a href="https://theconversation.com/ancient-dna-is-a-powerful-tool-for-studying-the-past-when-archaeologists-and-geneticists-work-together-111127">aDNA research raises as many questions as answers</a>. Finding central African ancestry throughout eastern and southern Africa prompts anthropologists to reconsider how interconnected these regions were in the distant past. This is important because central Africa has remained archaeologically understudied, in part because of political, economic and logistical challenges that make research there difficult. </p>
<p>Additionally, while genetic evidence supports a major demographic transition in Africa after 50,000 years ago, we still don’t know the key drivers. Determining what triggered the Later Stone Age transition will require closer examination of regional environmental, archaeological and genetic records to understand how this process unfolded across sub-Saharan Africa.</p>
<p>Finally, this study is a stark reminder that researchers still have <a href="https://theconversation.com/lesson-from-brazil-museums-are-not-forever-102692">much to learn from ancient individuals and artifacts</a> held in African museums, and highlights the <a href="https://theconversation.com/what-its-like-curating-ancient-fossils-a-palaeontologist-shares-her-story-96555">critical role of the curators</a> who steward these collections. While some human remains in this study were recovered within the past decade, others have been in museums for a half-century.</p>
<p>Even though technological advances are pushing back the time limits for aDNA, it is important to remember that scientists have only just begun to understand human diversity in Africa, past and present.</p>
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<p class="fine-print"><em><span>Elizabeth Sawchuk receives funding from the Social Sciences and Humanities Research Council of Canada. </span></em></p><p class="fine-print"><em><span>Jessica Thompson has received funding from the Leakey Foundation, National Geographic Society, Wenner-Gren Foundation, Australian Research Council, National Science Foundation, and Hyde Family Foundation. </span></em></p><p class="fine-print"><em><span>Mary Prendergast does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>
A new study doubles the age of ancient DNA in sub-Saharan Africa, revealing how people moved, mingled and had children together over the last 50,000 years.
Elizabeth Sawchuk, Banting Postdoctoral Fellow and Adjunct Professor of Anthropology, University of Alberta
Jessica Thompson, Assistant Professor of Anthropology, Yale University
Mary Prendergast, Associate Professor of Anthropology, Rice University
Licensed as Creative Commons – attribution, no derivatives.
tag:theconversation.com,2011:article/169284
2021-10-20T15:29:37Z
2021-10-20T15:29:37Z
Why scholars have created global guidelines for ancient DNA research
<figure><img src="https://images.theconversation.com/files/425679/original/file-20211011-17-e8rw09.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Ancient DNA holds a great deal of valuable information - but it must be researched ethically.</span> <span class="attribution"><span class="source">© Max Planck Institute for Evolutionary Anthropology</span></span></figcaption></figure><p>The field of <a href="https://www.sciencedirect.com/topics/medicine-and-dentistry/ancient-dna">ancient DNA</a> has grown rapidly in recent years, largely thanks to technological advancements. This work involves sampling human remains from long ago and analysing the DNA to understand human and population history, origins and evolution. </p>
<p>As with any scientific research, there are ethical questions to navigate. Some are fairly modern concerns. DNA contains all our genetic and biological information; these data, if unregulated, can be misused for medical and scientific research by anyone, including but not limited to scientists, governments, and big pharmaceutical companies. Other ethical concerns are rooted in history. For centuries, scientists have tested and obtained data on African people as though they were merely <a href="https://jacana.co.za/product/darwins-hunch-science-race-and-the-search-for-human-origins/">specimens, objects and subjects</a>. <a href="https://www.bbc.com/news/world-europe-52151722">These attitudes persist</a>.</p>
<p>These, then, are the key questions for anyone engaged in ancient DNA research: how can Africa’s genomes (and those from other places, especially elsewhere in the global South) be protected while its researchers contribute to <a href="https://www.ft.com/content/eed0555c-5e2b-11ea-b0ab-339c2307bcd4">the human story and understanding human history</a>? What is the most ethical way to do this research? How do scientists, for instance, proceed with obtaining consent from a community or families whose ancestors’ remains are being tested? What should they do when it’s not clear who the human remains descendants or communities are? And, crucially, how can the African continent’s ancient DNA be protected?</p>
<p>This last question is important because of humanity’s origin and deep historical roots in Africa. <a href="https://www.researchgate.net/publication/338960012_DNA_is_the_key_to_unlocking_our_ancient_African_past">African DNA</a> is found in all humans. Studying ancient DNA in Africa is valuable for understanding human evolution, population migrations, and human history locally, regionally and globally. </p>
<p>These questions of ethics have led to a diverse set of 64 scholars from 24 countries who are actively involved in ancient DNA research – myself among them – to develop a set of ethical guidelines for the discipline. These are outlined in our <a href="https://www.nature.com/articles/s41586-021-04008-x">new article</a> in the journal Nature.</p>
<p>Appropriate approaches to working with human ancient DNA differ across world contexts. That’s why so many specialists from varying regions and countries came together to develop these guidelines. They are not so detailed that they can’t be adapted for specific contexts, but are specific enough to offer a level of protection. The countries include Germany, India, Mexico and the US. From the African continent, researchers from Sudan, Kenya and South Africa contributed ideas and suggestions.</p>
<h2>Five guidelines</h2>
<p>My colleagues and I believe that the set of guidelines we’ve created are strong and universally applicable. We’ve committed to applying them in our own work.</p>
<p>The guidelines call for researchers to:</p>
<ol>
<li><p>abide by all regulations in the places where they work and from which the human remains originate </p></li>
<li><p>prepare a detailed plan prior to beginning any study </p></li>
<li><p>minimise damage to human remains </p></li>
<li><p>ensure data are made available following publication to allow critical re-examination of scientific findings </p></li>
<li><p>engage with other stakeholders and ensure respect and sensitivity to stakeholder perspectives.</p></li>
</ol>
<p>Our hope is that these guidelines will ensure ancient DNA research is always conducted to the highest ethical standards. We have also designed them in a way that will, we believe, address the issue of <a href="https://theconversation.com/how-a-partnership-is-closing-the-door-on-parachute-research-in-africa-102217">parachute research</a>. </p>
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<img alt="" src="https://images.theconversation.com/files/425685/original/file-20211011-19-p7qbcg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/425685/original/file-20211011-19-p7qbcg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/425685/original/file-20211011-19-p7qbcg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/425685/original/file-20211011-19-p7qbcg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/425685/original/file-20211011-19-p7qbcg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/425685/original/file-20211011-19-p7qbcg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/425685/original/file-20211011-19-p7qbcg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">No matter where it’s done, ancient DNA research must be done ethically.</span>
<span class="attribution"><span class="source">© Max Planck Institute for Evolutionary Anthropology</span></span>
</figcaption>
</figure>
<p>This refers to scientists from wealthy nations swooping into developing ones, collecting samples and data, then heading straight back home to analyse them. There is poor to little coordination with local researchers, scientists and community groups in the country the samples come from – and, ultimately, the resulting research predominantly benefits those in the global North. Historically this is well documented, and <a href="https://theconversation.com/global-health-still-mimics-colonial-ways-heres-how-to-break-the-pattern-121951">today</a> these ideas of testing on Africans are still pervasive. With the rise of ancient DNA research, there’s a risk of parachute research. </p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/ancient-dna-unearths-fascinating-secrets-but-what-about-the-ethics-85186">Ancient DNA unearths fascinating secrets. But what about the ethics?</a>
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<h2>A starting point</h2>
<p>My contributions to the subject follow on from <a href="https://doi.org/10.1038/s41576-020-00285-w">a paper</a> I published in 2020 explaining the robust rules and regulations for DNA studies on the living. I highlighted the gaps in South Africa’s heritage legislation with ancient DNA research and argued they should mirror each other. DNA, whether from the living or the dead, provides a lot of information about both – the implications for this research are far reaching.</p>
<p>In my own research, I hope the guidelines we’ve created will improve communication structures and respect for local community consultation processes and understanding the need for regular feedback and results returning in tangible ways back into community groups. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/skeletons-and-closets-how-one-university-reburied-the-dead-126607">Skeletons and closets: How one university reburied the dead</a>
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<p>The guidelines capture the values of transparency and open access data, engagement, respect, dignity and sensitivity that must be central to ancient DNA research.</p>
<p>The hope is that these principles will provide a starting point from which African countries can begin to improve consultation, prevent or lessen parachute research and develop strong local legislation to enshrine ethical ancient DNA research. It is critical that all ancient DNA researchers are held accountable: researchers in African countries need to be careful and responsible with the continent’s genetic material in the same way that those from wealthier countries need to avoid conducting parachute research.</p>
<p>The paper has been translated into more than 20 languages – among them Swahili, isiXhosa, Afrikaans, Arabic, French, German and Portuguese – to ensure that the guidelines are widely accessible.</p><img src="https://counter.theconversation.com/content/169284/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Victoria Gibbon receives funding from the National Research Foundation (NRF) of South Africa their financial assistance towards this research is hereby acknowledged. Opinions expressed, and conclusions arrived at, are those of the author and are not necessarily
attributed to these funding bodies.</span></em></p>
Studying ancient DNA in Africa is valuable for understanding human evolution, population migrations, and human history locally, regionally and globally.
Victoria Gibbon, Associate Professor in Biological Anthropology, Division of Clinical Anatomy and Biological Anthropology, University of Cape Town
Licensed as Creative Commons – attribution, no derivatives.