tag:theconversation.com,2011:/uk/topics/denisovans-1510/articlesDenisovans – The Conversation2023-05-02T12:14:34Ztag:theconversation.com,2011:article/1965552023-05-02T12:14:34Z2023-05-02T12:14:34ZEnigmatic 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 YorkRolf Quam, Associate Professor of Anthropology, Binghamton University, State University of New YorkLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2015692023-04-18T20:01:07Z2023-04-18T20:01:07ZDiseases gave us the rise of Christianity, the end of the Aztecs and public sanitation. How might future plagues change human history?<figure><img src="https://images.theconversation.com/files/517613/original/file-20230327-27-ualse4.jpg?ixlib=rb-1.1.0&rect=0%2C6%2C4439%2C3183&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Elena Mozhvilo/Unsplash</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>“Every once in a while a book lands on your desk that changes the way you perceive the world you live in, a book that fundamentally challenges your understanding of human history.” So began the blurb that came with this book. Aha! I thought. The usual advertising hyperbole, a gross exaggeration. </p>
<p>Yet <a href="https://www.penguin.com.au/books/pathogenesis-9781911709053">Pathogenesis</a> <em>did</em> challenge much of my understanding of world history. Who knew that if it wasn’t for an Ebola-like pandemic in the 2nd century CE, Christianity would never have become a world religion? Or that if it weren’t for retroviruses, women would be laying eggs rather than having live births? (According to the book’s author, a retrovirus inserted DNA into our ancestor’s genome that caused the placenta to develop.)</p>
<hr>
<p><em>Book review: Pathogenesis: How germs made history – by Jonathan Kennedy (Torva)</em></p>
<hr>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/517614/original/file-20230327-20-1geds5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/517614/original/file-20230327-20-1geds5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/517614/original/file-20230327-20-1geds5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=923&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517614/original/file-20230327-20-1geds5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=923&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517614/original/file-20230327-20-1geds5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=923&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517614/original/file-20230327-20-1geds5.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1160&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517614/original/file-20230327-20-1geds5.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1160&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517614/original/file-20230327-20-1geds5.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1160&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<p>However, this is not another book of Amazing Facts: it is a work of scholarship, with nearly 700 references and notes. At the same time, it is very readable, and even amusing at times. </p>
<p>Many books have been written about the impact of disease on civilisation. I have even written my own modest <a href="https://medium.com/@adrian.esterman/infectious-diseases-and-their-impact-on-civilisation-4eb8ac72cc5b">essay</a> on the topic. However,
Pathogenesis delves deeply into the social history of the world. </p>
<p>Jonathan Kennedy has a PhD in sociology from the University of Cambridge, and his sociological bent comes through strongly. In eight chapters, and some 350 pages, Kennedy takes us on a whirlwind tour of social history, describing how infectious diseases have shaped humanity at every stage. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/viruses-are-both-the-villains-and-heroes-of-life-as-we-know-it-169131">Viruses are both the villains and heroes of life as we know it</a>
</strong>
</em>
</p>
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<h2>‘It’s a bacterial world’</h2>
<p>Kennedy starts by describing the three great branches of living organisms, <a href="https://theconversation.com/from-peaceful-coexistence-to-potential-peril-the-bacteria-that-live-in-and-on-us-104110">bacteria</a>, <a href="https://microbiologysociety.org/why-microbiology-matters/what-is-microbiology/archaea.html">archaea</a>, and <a href="https://www.britannica.com/science/eukaryote">eukaryotes</a> – it is the latter that contains all complex life forms, including humans. However, fewer than 0.001% of all species are eukaryotes. </p>
<p>Bacteria, on the other hand, are the dominant life form on this planet. As Kennedy puts it, “it’s a bacterial world, and we’re just squatting here”. </p>
<p>Our own species, <em><a href="https://theconversation.com/rethinking-homo-sapiens-the-story-of-our-origins-gets-dizzyingly-complicated-99760">Homo sapiens</a></em>, arose some 315,000 years ago, living for the most part in Africa. At the same time, human species such as Neanderthals and <a href="https://theconversation.com/dna-from-elusive-human-relatives-the-denisovans-has-left-a-curious-mark-on-modern-people-in-new-guinea-196113">Denisovans</a> spread out into Europe. However, about 50,000 years ago, <em>Homo sapiens</em> burst out of Africa and spread across the world, while all other human species simply vanished. There are many <a href="https://www.scientificamerican.com/article/how-homo-sapiens-became-the-ultimate-invasive-species/">theories</a> as to why and how this occurred – for example, perhaps <em>Homo sapiens</em> were just smarter. </p>
<p>However, Kennedy proposes his own theory. Because <em>Homo sapiens</em> lived primarily in Africa, they were exposed to many pathogens, and eventually acquired genetic changes that gave them some protection. The exodus out of Africa exposed other species to these pathogens, causing their demise. </p>
<p>He describes the <a href="https://theconversation.com/who-were-the-mysterious-neolithic-people-that-enabled-the-rise-of-ancient-egypt-heres-what-weve-learned-on-our-digs-121070">Neolithic</a> revolution, which took place about 12,000 years ago and which saw the change from hunter-gatherers to farmers. Because of their nomadic existence in small groups, hunter-gatherers tended to be relatively healthy, with an average lifespan of 72 - better than the average lifespan in some countries today! </p>
<p>It has always been assumed that this revolution was a good thing, bringing better nutrition and more leisure time. However, in Kennedy’s view, the Neolithic revolution led to the emergence of despotism, inequality, poverty and backbreaking work. He describes how settlement and the farming of domestic animals led to the emergence of zoonotic diseases – that is, <a href="https://theconversation.com/preventing-future-pandemics-starts-with-recognizing-links-between-human-and-animal-health-167617">diseases spread by animals</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517617/original/file-20230327-24-pz4erz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/517617/original/file-20230327-24-pz4erz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517617/original/file-20230327-24-pz4erz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517617/original/file-20230327-24-pz4erz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517617/original/file-20230327-24-pz4erz.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517617/original/file-20230327-24-pz4erz.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517617/original/file-20230327-24-pz4erz.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517617/original/file-20230327-24-pz4erz.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">Settlement and the farming of domestic animals led to the emergence of diseases spread by animals.</span>
<span class="attribution"><span class="source">kallerna/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/disease-evolution-our-long-history-of-fighting-viruses-54569">Disease evolution: our long history of fighting viruses</a>
</strong>
</em>
</p>
<hr>
<h2>Plagues and social upheavals</h2>
<p>In a chapter on ancient plagues, Kennedy quotes from Monty Python’s <a href="https://theconversation.com/life-of-brian-at-40-an-assertion-of-individual-freedom-that-still-resonates-114743">The Life of Brian</a>: </p>
<blockquote>
<p>All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us?</p>
</blockquote>
<p>He points out that Roman cities were, in fact, “filthy, stinking and disease-ridden”, and goes on to describe the great plagues <a href="https://theconversation.com/how-3-prior-pandemics-triggered-massive-societal-shifts-146467">that weakened the Roman Empire</a>. The first was the Antonine Plague, possibly caused by smallpox. This was followed some 70 years later by the Plague of Cyprian from AD 249-262, which led to the splitting of the Roman Empire and the rise of Christianity. </p>
<p>Kennedy completes this chapter with a description of the Plague of Justinian, caused by bubonic plague. The massive deaths caused by this epidemic led to the demise of the Roman Empire, and the Muslim conquest of the Middle East. </p>
<p>In the period 1346–53, the <a href="https://theconversation.com/did-the-black-death-give-birth-to-modern-plagues-3820">Black Death</a> tore through North Africa and Europe, killing an <a href="https://en.wikipedia.org/wiki/Black_Death">estimated</a> 75 million to 200 million people. Kennedy describes the devastation and huge social upheavals that resulted from this pandemic. Until then, the Roman Catholic Church dominated society. But:</p>
<blockquote>
<p>During the Black Death and subsequent plague outbreaks, people looked to the Church for comfort. All too often they didn’t find it. </p>
</blockquote>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517616/original/file-20230327-22-23ih7j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/517616/original/file-20230327-22-23ih7j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517616/original/file-20230327-22-23ih7j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=486&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517616/original/file-20230327-22-23ih7j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=486&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517616/original/file-20230327-22-23ih7j.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=486&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517616/original/file-20230327-22-23ih7j.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=611&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517616/original/file-20230327-22-23ih7j.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=611&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517616/original/file-20230327-22-23ih7j.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 Black Death killed an estimated 75–200 million people in Europe and North Africa. Hugo Simberg Black Death.</span>
<span class="attribution"><span class="source">Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>This led to the rise of Protestantism, aided by the invention of the printing press - a shortage of labour encouraged the development of such labour-saving devices. Over the next 200 years, waves of plague repeatedly hit Europe. A quarantine system was developed in Venice, and <em>cordon sanitaires</em> established, to prevent movement of people between cities - ring any bells? </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/did-the-black-death-give-birth-to-modern-plagues-3820">Did the Black Death give birth to modern plagues?</a>
</strong>
</em>
</p>
<hr>
<h2>Pathogens as New World killers</h2>
<p>In the period from 1500 onwards, white colonialists nearly wiped out indigenous people by infecting them. Kennedy starts with the early 16th century, when Spanish conquistador Hernán Cortés led an expedition to Mexico. His arrival <a href="https://theconversation.com/how-smallpox-devastated-the-aztecs-and-helped-spain-conquer-an-american-civilization-500-years-ago-111579">introduced smallpox</a>, which resulted in the total destruction of the Aztec Empire within just two years. However, this was just the start. </p>
<p>In the early 1530s, Mexico was hit by an epidemic of <a href="https://theconversation.com/measles-new-efforts-needed-to-stop-an-old-disease-13706">measles</a> that killed 80% of its population, making it the deadliest epidemic in recorded history. Over the following decades, across the whole of the Americas, the introduction of infectious diseases from Europe resulted in a 90% fall in the population. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/517624/original/file-20230327-15-s0x2ks.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/517624/original/file-20230327-15-s0x2ks.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/517624/original/file-20230327-15-s0x2ks.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=441&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517624/original/file-20230327-15-s0x2ks.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=441&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517624/original/file-20230327-15-s0x2ks.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=441&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517624/original/file-20230327-15-s0x2ks.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=554&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517624/original/file-20230327-15-s0x2ks.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=554&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517624/original/file-20230327-15-s0x2ks.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=554&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Hernán Cortés brought smallpox to Mexico, resulting in the total destruction of the Aztec Empire within two years, as illustrated in this 16th-century drawing of Aztec smallpox victims.</span>
<span class="attribution"><span class="source">Wikimedia Commons</span></span>
</figcaption>
</figure>
<p>However, during this period, it wasn’t just the New World that was profoundly affected by pathogens. On the west coast of Africa, explorers and would-be colonialists died in droves from <a href="https://theconversation.com/worlds-first-mass-malaria-vaccine-rollout-could-prevent-thousands-of-children-dying-169457">malaria</a> and <a href="https://theconversation.com/zika-dengue-yellow-fever-what-are-flaviviruses-53969">yellow fever</a>. </p>
<p>Interestingly, Kennedy starts his chapter on revolutionary plagues with the murder of <a href="https://theconversation.com/george-floyd-deserved-a-better-life-a-new-book-charts-his-trajectory-from-poverty-to-the-us-prison-industrial-complex-and-the-impact-of-his-death-182947">George Floyd</a> and the <a href="https://theconversation.com/the-black-lives-matter-movement-has-provoked-a-cultural-reckoning-about-how-black-stories-are-told-149544">Black Lives Matter</a> movement, before delving deep into the history of slavery. He describes slavery in Greek and Roman times, and the booming trade in slaves in the medieval Mediterranean. </p>
<p>The association between black Africans and <a href="https://theconversation.com/slavery-is-not-a-crime-in-almost-half-the-countries-of-the-world-new-research-115596">slavery</a> only began in the 15th century. In fact, only 3% of the 12.5 million humans trafficked across the Atlantic ended up in the United States. The most common destinations of the slave ships were the European colonies in the Caribbean, where African slave labour was first used more than a century before their shipment to North America. </p>
<p>Meanwhile, in the Caribbean, slave labour from tropical West Africa toiled on sugar plantations owned by the English, Spanish, French and Dutch. Yellow fever carried by mosquitoes wiped out many of the Europeans, including military garrisons, leading to slave revolts.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/friday-essay-a-slave-state-how-blackbirding-in-colonial-australia-created-a-legacy-of-racism-187782">Friday essay: a slave state - how blackbirding in colonial Australia created a legacy of racism</a>
</strong>
</em>
</p>
<hr>
<h2>Diseases ‘thrived’ in Dickensian habitats</h2>
<p>When Kennedy switches his focus to Britain, and the industrial revolution, he describes it as the change from a Thomas Hardy novel to one by <a href="https://theconversation.com/great-expectations-by-charles-dickens-class-prejudices-the-convict-stain-and-a-corpse-bride-159816">Charles Dickens</a>. The crowded and unsanitary conditions in working-class urban districts created new habitats, in which pathogens thrived. </p>
<p>Kennedy again evokes Monty Python to invoke the scenery of those days, reminding readers of the famous four Yorkshiremen sketch. The scene made me think of a different quote from the same sketch:</p>
<blockquote>
<p>You were lucky to have a house! We used to live in one room, all hundred and twenty-six of us, no furniture. Half the floor was missing; we were all huddled together in one corner for fear of falling!</p>
</blockquote>
<p>Every Epidemiology 101 course covers the story of <a href="https://www.newscientist.com/people/john-snow/">John Snow</a> (no – not the “Winter is coming” one!). <a href="https://www.cdc.gov/csels/dsepd/ss1978/lesson1/section2.html">Two decades</a> before the development of the microscope, Snow examined cholera outbreaks to discover the cause of disease and how to prevent it. </p>
<figure class="align-left zoomable">
<a href="https://images.theconversation.com/files/517625/original/file-20230327-14-jix57.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/517625/original/file-20230327-14-jix57.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/517625/original/file-20230327-14-jix57.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=619&fit=crop&dpr=1 600w, https://images.theconversation.com/files/517625/original/file-20230327-14-jix57.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=619&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/517625/original/file-20230327-14-jix57.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=619&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/517625/original/file-20230327-14-jix57.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=778&fit=crop&dpr=1 754w, https://images.theconversation.com/files/517625/original/file-20230327-14-jix57.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=778&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/517625/original/file-20230327-14-jix57.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=778&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">John Snow proved in 1854 that cholera is a waterborne disease: a London pub is named for him.</span>
<span class="attribution"><a class="source" href="https://www.geograph.org.uk/profile/6699">ceridwen/Wikimedia Commons</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>During the third UK cholera outbreak in 1854, Snow famously removed London’s Broad Street water pump, to demonstrate that cholera was a waterborne disease. For those interested, there is a <a href="https://londonspubswherehistoryreallyhappened.wordpress.com/2019/03/05/john-snow/">John Snow</a> pub in London. Kennedy, of course, includes this story in his book.</p>
<p>Kennedy points out that 3.5 billion people – half of the world’s population – have no access to proper toilets, while a billion don’t have clean drinking water and 1.5 million people, mainly children, die every year from waterborne diarrhoeal diseases. </p>
<p>We still have massive <a href="https://theconversation.com/explainer-why-cholera-remains-a-public-health-threat-74444">cholera outbreaks</a>, especially in areas where normal life has been disrupted by war or natural disasters. <a href="https://theconversation.com/tuberculosis-kills-as-many-people-each-year-as-covid-19-its-time-we-found-a-better-vaccine-151590">Tuberculosis</a> still kills 1.2 million people a year, despite the availability of antibiotics. Malaria kills another 600,000. </p>
<p>Finally in this section, he briefly covers <a href="https://theconversation.com/covid-hospitalisations-and-deaths-are-rising-faster-than-cases-but-that-doesnt-mean-more-severe-disease-187163">COVID</a>. He points out that not everyone in the world benefited from the medical advances that came about because of COVID, and the self-interested actions of high-income countries have deprived the poorer countries. As he puts it, “pathogens thrive on inequality and injustice”. </p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/fleas-to-flu-to-coronavirus-how-death-ships-spread-disease-through-the-ages-137061">Fleas to flu to coronavirus: how 'death ships' spread disease through the ages</a>
</strong>
</em>
</p>
<hr>
<h2>Future plagues</h2>
<p>Kennedy concludes by looking at future plagues. He points out humanity’s precarious position: we live on a planet dominated by bacteria and viruses. He believes our best chance of surviving the threat posed by pathogens will come from working collaboratively and reducing inequality both within and between countries. </p>
<p>Based on its title, I assumed this book would be about the role of pathogens in shaping civilisation. Instead, I found a social history of the world, with the odd foray into diseases and their influence on society. Nonetheless, I thoroughly enjoyed the book, and can highly recommend it to those with an interest in history, sociology and epidemiology.</p><img src="https://counter.theconversation.com/content/201569/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Adrian Esterman 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>This whirlwind tour of social history describes how infectious diseases have shaped humanity at every stage. It suggests reducing inequality will give us our best chance of surviving future plagues.Adrian Esterman, Professor of Biostatistics and Epidemiology, University of South AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1961132022-12-08T19:24:21Z2022-12-08T19:24:21ZDNA 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>
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<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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<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>
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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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<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>
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<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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<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 MelbourneDavide Vespasiani, Post-doctoral researcher, The University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1919132022-10-07T12:22:44Z2022-10-07T12:22:44ZOur ‘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>
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<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>
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<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>
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<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 UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1918992022-10-04T23:15:56Z2022-10-04T23:15:56ZWhat’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>
<p><iframe id="5Fzpd" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/5Fzpd/2/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<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>
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<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>
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</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 UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1918052022-10-03T19:09:41Z2022-10-03T19:09:41ZNobel prize: Svante Pääbo’s ancient DNA discoveries offer clues as to what makes us human<p>The <a href="https://www.nobelprize.org/prizes/medicine/2022/press-release/">Nobel prize</a> in physiology or medicine for 2022 has been awarded to Svante Pääbo from the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, “for his discoveries concerning the genomes of extinct hominins and human evolution”. </p>
<p>In other words, Pääbo has been awarded the prestigious prize for having sequenced the genomes of our extinct relatives, the Neanderthals and Denisovans, and for the fact that these discoveries have resulted in novel insights into human evolution. </p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1576867617536503808"}"></div></p>
<p>Pääbo is widely regarded as having pioneered the field of <a href="https://www.pnas.org/doi/10.1073/pnas.86.6.1939?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub++0pubmed">ancient DNA</a>, a research area dedicated to the recovery and analysis of DNA from historic and prehistoric remains.</p>
<p>Although Pääbo did his PhD in medical science at Uppsala University in Sweden in <a href="https://fof.se/artikel/2005/7/han-laser-forntidens-dna/">the early 1980s</a>, he also studied Egyptology when he was at Uppsala. It was a logical next step that he took tools from molecular biology, garnered from his expertise in medical science, to better understand human prehistory. </p>
<h2>Extracting DNA from ancient bones</h2>
<p>Beginning in the 1980s, Pääbo studied <a href="https://academic.oup.com/nar/article/16/20/9775/2378566">ancient DNA</a> in material ranging from mummified humans to <a href="https://www.pnas.org/doi/10.1073/pnas.86.6.1939">extinct ground sloths</a>. This work was <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC309938/pdf/nar00065-0302.pdf">technically challenging</a> because ancient DNA is significantly degraded and can be contaminated.</p>
<p>In the decade that followed, he developed a series of <a href="https://pubmed.ncbi.nlm.nih.gov/8020612/">methods and guidelines</a> to recover and interpret authentic DNA and to minimise the risk of contamination from modern sources, especially from contemporary humans.</p>
<p>In the early 1990s, there was significant excitement in the field about the possibility of recovering <a href="https://www.science.org/doi/10.1126/science.7973705">DNA from dinosaurs</a>. However, based on his knowledge of how DNA <a href="https://www.cell.com/fulltext/S0092-8674(00)80306-2">degrades over time</a>, Pääbo remained sceptical that DNA could survive such a long time. He was later proven right.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/six-recent-discoveries-that-have-changed-how-we-think-about-human-origins-190274">Six recent discoveries that have changed how we think about human origins</a>
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<p>For many of his colleagues, it was clear that Pääbo’s goal was always to recover Neanderthal DNA. But he took his time and carefully developed the methods for recovering and authenticating ancient DNA until these methods were mature enough to accomplish this objective.</p>
<p>Finally, in 1997, Pääbo and his colleagues published the first Neanderthal <a href="https://www.sciencedirect.com/science/article/pii/S0092867400803104">DNA sequences</a>. In 2010 this was followed by the entire <a href="https://www.science.org/doi/10.1126/science.1188021">Neanderthal genome</a> (that is, all the genetic information stored in the DNA of one Neanderthal).</p>
<p>Only a few years later, the group also published the genome from a previously unknown type of human, <a href="https://www.science.org/doi/10.1126/science.1224344">the Denisovans</a>, distantly related to Neanderthals. This sequencing was based on a 40,000-year-old fragment of bone discovered in the Denisova cave in Siberia.</p>
<figure class="align-center ">
<img alt="A depiction of a Neanderthal family wandering through the jungle." src="https://images.theconversation.com/files/487855/original/file-20221003-12-wwstjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/487855/original/file-20221003-12-wwstjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/487855/original/file-20221003-12-wwstjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/487855/original/file-20221003-12-wwstjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/487855/original/file-20221003-12-wwstjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/487855/original/file-20221003-12-wwstjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/487855/original/file-20221003-12-wwstjv.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">Pääbo’s discoveries show us that gene sequences from our extinct relatives influence the physiology of modern-day humans.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/tribe-huntergatherers-wearing-animal-skin-holding-1595953543">Gorodenkoff/Shutterstock</a></span>
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<p>By virtue of being able to compare these with human genomes, one of the most important findings of Pääbo’s work has been that many modern humans carry a small proportion of DNA from Neanderthals and Denisovans. Modern humans picked up these snippets of DNA through hybridisation, when modern and archaic humans mixed, as modern humans expanded across Eurasia during the last ice age.</p>
<p>For example, particular Neanderthal genes affect how our immune system <a href="https://www.pnas.org/doi/10.1073/pnas.2026309118">reacts to infections</a>, including COVID-19. The Denisovan version of a gene called EPAS1, meanwhile, helps people survive at high altitudes. It’s common among modern-day Tibetans.</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/neanderthals-died-out-40-000-years-ago-but-there-has-never-been-more-of-their-dna-on-earth-189021">Neanderthals died out 40,000 years ago, but there has never been more of their DNA on Earth</a>
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<p>At the same time, in comparing the genomes of Neanderthals and Denisovans with those of modern humans, Pääbo and his colleagues have been able to highlight genetic mutations that <a href="https://pubmed.ncbi.nlm.nih.gov/24679537/">are not shared</a>.
A large proportion of these are connected to how the brain develops.</p>
<p>By revealing genetic differences that distinguish living humans from our extinct ancestors, Pääbo’s influential discoveries provide the basis for exploring what makes us uniquely human.</p><img src="https://counter.theconversation.com/content/191805/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Love Dalén receives funding from the Swedish Research Council.</span></em></p><p class="fine-print"><em><span>Anders Götherström receives funding from the Swedish Research Council. </span></em></p>The Nobel Prize in physiology or medicine for 2022 has been awarded to Svante Pääbo, whose discoveries have been pivotal to the way we understand our evolutionary history.Love Dalén, Professor in Evolutionary Genetics, Centre for Palaeogenetics, Stockholm UniversityAnders Götherström, Professor in Molecular Archaeology, Department of Archaeology and Classical Studies, Stockholm UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1792902022-05-17T20:00:28Z2022-05-17T20:00:28ZA fossil tooth places enigmatic ancient humans in Southeast Asia<figure><img src="https://images.theconversation.com/files/459634/original/file-20220426-22-rl38zi.JPG?ixlib=rb-1.1.0&rect=0%2C16%2C7491%2C2784&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Fabrice Demeter (University of Copenhagen / CNRS Paris)</span>, <span class="license">Author provided</span></span></figcaption></figure><p>What do a finger bone and some teeth found in the frigid Denisova Cave in Siberia’s Altai mountains have in common with fossils from the balmy hills of tropical northern Laos? </p>
<p>Not much, until now: in a Laotian cave, an international team of researchers including ourselves has <a href="https://www.nature.com/articles/s41467-022-29923-z">discovered a tooth</a> belonging to an ancient human previously only known from icy northern latitudes – a Denisovan.</p>
<p>The find shows these long-lost relatives of <em>Homo sapiens</em> inhabited a wider area and range of environments than we previously knew, confirming hints found in the DNA of modern human populations from Southeast Asia and Australasia.</p>
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<em>
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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>
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<h2>Who were the Denisovans?</h2>
<p>Little is known about these distant cousins of modern humans, except that they once lived in Asia, were related to and interacted with the better-known Neanderthals, and are now extinct. </p>
<p>The first traces of Denisovans were only found in 2010, with the <a href="https://www.nature.com/articles/nature09710">discovery</a> of an innocuous finger bone in remote Denisova Cave. The extreme cold of the cave meant some ancient DNA was preserved in the bone – and the DNA revealed the finger had belonged to an unknown species of human.</p>
<p>This discovery changed the course of human evolutionary studies, and the newly discovered humans were named Denisovans after the cave where the fossil was found.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/461151/original/file-20220504-14-lmc80h.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/461151/original/file-20220504-14-lmc80h.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/461151/original/file-20220504-14-lmc80h.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/461151/original/file-20220504-14-lmc80h.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/461151/original/file-20220504-14-lmc80h.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/461151/original/file-20220504-14-lmc80h.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/461151/original/file-20220504-14-lmc80h.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">
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<span class="caption">The first traces of the Denisovans were found at Denisova Cave in Siberia in 2010.</span>
<span class="attribution"><span class="source">Mike Morley (Flinders University)</span>, <span class="license">Author provided</span></span>
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<p>Fossilised teeth from Denisovans were <a href="https://www.pnas.org/doi/abs/10.1073/pnas.1519905112">later discovered</a> in the <a href="https://www.science.org/doi/10.1126/science.aam9695">same cave</a>. Two upper and one lower molar were found in sediments that were dated to between 195,000 and 52,000 years ago. </p>
<p>Meanwhile, it was found that <a href="https://www.nature.com/articles/nature09710">genes from Denisovans survived</a> in modern day people from Southeast Asia and Australasia. This implied that the Denisovans had dispersed over a far larger area than anticipated. </p>
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<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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<h2>The hunt for more fossils</h2>
<p>The hunt was on to find more evidence of these humans outside Russia, but scientists had no idea what they actually looked like. For the first time in history we knew more about a human’s DNA than their anatomy!</p>
<p>The next twist came when a <a href="https://www.nature.com/articles/s41586-019-1139-x">160,000-year-old Denisovan jawbone</a> surfaced on the Tibetan Plateau, giving the scientific community a tantalising glimpse of what the bodies of these ancient humans were like and where they lived. </p>
<p>But questions remained: just how far did they spread in Asia, and how did their genetic imprint survive in Southeast Asians and Australasians? </p>
<p>Clearly Denisovans could live in the cold environments of Siberia and Tibet, but could they have also occupied a completely different ecological niche and adapted to a tropical climate?</p>
<h2>Tam Ngu Hao 2 (Cobra Cave)</h2>
<p>Enter a new cave found by an international (Laos–French–American–Australian) team in northern Laos in 2018, close to the famous Tam Pa Ling cave where 70,000-year-old <a href="https://www.pnas.org/doi/10.1073/pnas.1208104109">modern human fossils</a> were found. </p>
<p>The site, named Tam Ngu Hao 2 (or Cobra Cave), was found high up in the limestone mountains and contained remnants of old cave sediment packed with fossils.</p>
<p>The cave sediments contained teeth from giant herbivores, such as ancient elephants and rhinos that liked to live in woodland environments. The teeth were likely washed into the cave during a flooding event that deposited the sediments and fossils. </p>
<p>These sediments were covered by a layer of very hard rock called flowstone, which is formed by water flowing over the cave floor. The sediments and fossils were dated by this study to provide an age for the time of deposition in the cave, and by association a minimum age for the death of the animals.</p>
<h2>A young girl’s tooth</h2>
<p>A human tooth (a lower permanent molar) was found in the cave sediments, but we could not initially identify what species of human it came from. The humid conditions in Laos meant that the ancient DNA was not preserved. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/461153/original/file-20220504-13-li3i3m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/461153/original/file-20220504-13-li3i3m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/461153/original/file-20220504-13-li3i3m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=686&fit=crop&dpr=1 600w, https://images.theconversation.com/files/461153/original/file-20220504-13-li3i3m.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=686&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/461153/original/file-20220504-13-li3i3m.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=686&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/461153/original/file-20220504-13-li3i3m.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=862&fit=crop&dpr=1 754w, https://images.theconversation.com/files/461153/original/file-20220504-13-li3i3m.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=862&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/461153/original/file-20220504-13-li3i3m.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=862&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 tooth likely belonged to a young Denisovan girl who lived around 150,000 years ago.</span>
<span class="attribution"><span class="source">Fabrice Demeter (University of Copenhagen / CNRS Paris)</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We did however find ancient proteins that suggested the tooth came from a young, likely female, human – probably between 3.5 and 8.5 years old. </p>
<p>After very detailed analysis of the shape of this tooth, our team identified many similarities to the Denisovan teeth found on the Tibetan Plateau. This suggested the tooth’s owner was most likely a Denisovan who lived between 164,000 and 131,000 years ago in the warm tropics.</p>
<h2>An ancient human hotspot</h2>
<p>This fossil represents the first discovery of Denisovans in Southeast Asia, and shows that Denisovans were at least as far south as Laos. This is in agreement with the genetic evidence found in modern day Southeast Asian populations. </p>
<p>They may have been just at home in the balmy tropical climates of Laos as the icy conditions of northern Europe and the high-altitude environments of the Tibetan Plateau. This suggests the Denisovans were very good at adapting to diverse environments. </p>
<p>It would seem that Southeast Asia was a hotspot of diversity for humans. At least five different species set up camp there at different times: <em>Homo erectus</em>, the Denisovans/Neanderthals, <em>Homo floresiensis</em>, <em>Homo luzonensis</em>, and <em>Homo sapiens</em>. </p>
<p>How many of these species overlapped and interacted? Another fossil discovered in the dense network of Southeast Asian caves could provide the next clue to understanding these complex relationships.</p><img src="https://counter.theconversation.com/content/179290/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kira Westaway receives funding from the Australian Research Council (ARC) and the Leakey Foundation</span></em></p><p class="fine-print"><em><span>Mike W Morley receives funding from the Australian Research Council (ARC). </span></em></p><p class="fine-print"><em><span>Renaud Joannes-Boyau receives funding from the Australian Research Council (ARC).</span></em></p>The mysterious Denisovans left DNA traces in populations across Southeast Asia and Australasia, but until now no physical signs of their presence outside Eurasia had been found.Kira Westaway, Associate professor, Macquarie UniversityMike W. Morley, Associate Professor, Flinders UniversityRenaud Joannes-Boyau, Associate Professor, Southern Cross UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1615852021-06-23T20:04:12Z2021-06-23T20:04:12ZDirty secrets: sediment DNA reveals a 300,000-year timeline of ancient and modern humans living in Siberia<figure><img src="https://images.theconversation.com/files/407374/original/file-20210621-35447-1spt3ea.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Collection of sediment DNA samples in the Main Chamber of Denisova Cave.</span> <span class="attribution"><span class="source">Bert Roberts</span>, <span class="license">Author provided</span></span></figcaption></figure><p>In the foothills of the Altai Mountains in southern Siberia lies Denisova Cave. It is the only site in the world known to have been inhabited by the eponymous Denisovans and their close relatives the Neanderthals (<em>Homo neanderthalensis</em>) — which <a href="https://www.nature.com/articles/d41586-018-06004-0">overlapped at times</a> — as well as by some of the earliest modern humans (<em>Homo sapiens</em>) to have dispersed into northern Asia.</p>
<p>Our <a href="https://www.nature.com/articles/s41586-021-03675-0">new study</a> pieces together the history of this site over the past 300,000 years from fragments of ancient DNA that survived in the cave sediments. Our findings reveal multiple turnovers of archaic and modern humans during this period, as well as major changes in the diversity of other animals.</p>
<p>We discovered Denisovans were the earliest toolmakers at the site, while Neanderthals were the sole human occupants between about 130,000 and 80,000 years ago. The first modern humans arrived much later, just as the last Denisovans and Neanderthals were leaving the scene.</p>
<p>We also detected marked changes in the types of human and animal DNA around 200,000 and 100,000 years ago, coincident with major shifts in climate and environmental conditions.</p>
<h2>Genetic ghosts</h2>
<p>Excavations in the cave by our Russian colleagues have unearthed about a dozen fossils of Denisovans and Neanderthals over the past 40 years, but none of modern humans. </p>
<p>Rather, the presence of modern humans at the cave has been surmised based on the recovery of artefacts made from stone, animal bones and teeth, mammoth ivory, ostrich eggshells, marble and gemstones.</p>
<p>The rarity of fossils at the site has also meant that questions persist about when different groups of humans occupied the cave, and which of them was responsible for making specific artefacts.</p>
<p>We managed to put flesh on the missing bones by using genetic traces of ancient humans and various other mammals preserved in the cave sediments. And we did so without having to find more fossils.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/403446/original/file-20210530-23-xbvsni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403446/original/file-20210530-23-xbvsni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403446/original/file-20210530-23-xbvsni.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403446/original/file-20210530-23-xbvsni.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403446/original/file-20210530-23-xbvsni.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403446/original/file-20210530-23-xbvsni.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403446/original/file-20210530-23-xbvsni.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">Project leader, Matthias Meyer, in the ancient DNA clean lab at the Max Planck Institute for Evolutionary Anthropology.</span>
<span class="attribution"><span class="source">Max Planck Institute for Evolutionary Anthropology</span></span>
</figcaption>
</figure>
<p>Our latest work is the most comprehensive study yet of ancient DNA extracted from sediment at any single site in the world. It builds on our <a href="https://science.sciencemag.org/content/356/6338/605">trailblazing research</a> published in 2017.</p>
<p>We extracted mitochondrial DNA from more than 700 samples and anchored them to a <a href="https://www.nature.com/articles/s41586-018-0843-2">timeline</a> for Denisova Cave, generating a detailed picture of which humans and animals were present at this famous site at various times in the past.</p>
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<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>
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<h2>Turbulent times</h2>
<p>We retrieved ancient human DNA from 175 sediment samples — more than ten times the number of human fossils found at the site. Several interesting findings emerged from our genetic analyses.</p>
<p>We found Denisovans were present at the cave, on and off, from 250,000 years ago until 60,000 years ago. And they were the only humans at the site between 250,000 and 200,000 years ago, so we can now say with more confidence they likely produced the stone tools recovered from these layers. </p>
<p>Denisovan fossils and ancient DNA have been found at only one <a href="https://theconversation.com/how-midnight-digs-at-a-holy-tibetan-cave-opened-a-window-to-prehistoric-humans-living-on-the-roof-of-the-world-148927">other site</a>, on the edge of the Tibetan Plateau.</p>
<p>Meanwhile, Neanderthals first appeared at Denisova Cave about 200,000 years ago, with a variety of DNA that was previously unknown. They vanished from the site about 40,000 years ago, around the same time Neanderthals disappeared in other parts of Eurasia.</p>
<p>Importantly, we could only find traces of Neanderthal DNA in sediments dated to between 130,000 and 80,000 years ago at Denisova Cave — and none of Denisovans.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/404606/original/file-20210605-27-1ye28kn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/404606/original/file-20210605-27-1ye28kn.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=699&fit=crop&dpr=1 600w, https://images.theconversation.com/files/404606/original/file-20210605-27-1ye28kn.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=699&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/404606/original/file-20210605-27-1ye28kn.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=699&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/404606/original/file-20210605-27-1ye28kn.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=878&fit=crop&dpr=1 754w, https://images.theconversation.com/files/404606/original/file-20210605-27-1ye28kn.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=878&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/404606/original/file-20210605-27-1ye28kn.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=878&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Summary timeline of the different types of human, bear and hyaena DNA in sediments at Denisova Cave. White gaps indicate missing parts of the sedimentary sequence. The graph on the left shows the changes in climate between relatively cold and warm conditions recorded in drill cores from Lake Baikal, also in southern Siberia.</span>
<span class="attribution"><span class="source">Bert Roberts</span></span>
</figcaption>
</figure>
<p>This time interval coincides with a major change in Earth’s climate: the start of the last interglacial. This was a relatively warm period similar to the present. It marked a switch from one type of Denisovan DNA before 130,000 years ago to another after 80,000 years ago.</p>
<p>This matches previous findings from genetic analysis of Denisovan fossils, which indicated a possible turnover in Denisovan populations. It also coincides with a population replacement of <a href="https://science.sciencemag.org/content/372/6542/eabf1667.full">Neanderthals in Spain</a> about 100,000 years ago — again identified from ancient DNA in cave sediments.</p>
<p>We also recovered the ancient DNA of modern humans from sediments deposited at Denisova Cave within the last 60,000 years. No modern human fossils have been found at the site, so these traces of DNA — from the same layers as the jewellery and pendants made from stone, bone, tooth and ivory — are the first direct evidence of <em>Homo sapiens</em>’ presence at the cave.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/403456/original/file-20210530-15-1thvbk4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/403456/original/file-20210530-15-1thvbk4.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=346&fit=crop&dpr=1 600w, https://images.theconversation.com/files/403456/original/file-20210530-15-1thvbk4.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=346&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/403456/original/file-20210530-15-1thvbk4.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=346&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/403456/original/file-20210530-15-1thvbk4.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=435&fit=crop&dpr=1 754w, https://images.theconversation.com/files/403456/original/file-20210530-15-1thvbk4.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=435&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/403456/original/file-20210530-15-1thvbk4.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=435&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Selection of stone tools and personal ornaments made from bone, tooth and ivory recovered from the same sediment layers as modern human ancient DNA.</span>
<span class="attribution"><span class="source">Institute of Archaeology and Ethnography of the Siberian Branch of the Russian Academy of Sciences.</span></span>
</figcaption>
</figure>
<h2>Denisova zoo</h2>
<p>We recovered other ancient animal DNA from 94% of the sediment samples. This is providing new vistas into cave use by more than 12 taxonomic families of mammals, including species such as bear, hyena, wolf and woolly mammoth.</p>
<p><a href="https://www.nature.com/articles/s41598-019-49930-3">Previous studies</a> have shown the cave was occupied at times by hyenas and bears. Our findings take this further, revealing cave bears dominated between 300,000 and 200,000 years ago, after which brown bears became more abundant.</p>
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Read more:
<a href="https://theconversation.com/dishing-the-dirt-sediments-reveal-a-famous-early-human-cave-site-was-also-home-to-hyenas-and-wolves-122458">Dishing the dirt: sediments reveal a famous early human cave site was also home to hyenas and wolves</a>
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<p>We also identified two major shifts in the types of hyena present at different times, with turnovers occurring when climatic conditions changed from relatively warm to cold 200,000 years ago, and from relatively cold to warm 100,000 years ago.</p>
<p>The timing of these turnovers, coupled with the patterns we discovered for Denisovans and Neanderthals, suggests these events were likely connected to environmental changes.</p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/aqdu2vjuCUY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A guided tour of our key findings, presented by the lead author of the study, Elena Zavala from the Max Planck Institute for Evolutionary Anthropology.</span></figcaption>
</figure>
<h2>Sediment diaries</h2>
<p>The power of sediment DNA lies in the fact that sediments are ubiquitous at archaeological and palaeontological sites. Even tiny samples can contain genetic traces of a variety of animals — including humans — in the absence of fossils.</p>
<p>Sediments also often contain plant remains and other materials that can be used to reconstruct ancient environments, with timelines obtained by <a href="https://www.nature.com/articles/520438a">directly dating</a> sediment grains.</p>
<p>By sampling sites with high densities of sediment DNA, the ebb and flow of humans and other animals can be compared to records of past environmental change. Making these crucial connections can help illuminate the dark corners of our planet’s history.</p><img src="https://counter.theconversation.com/content/161585/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elena Zavala receives funding from the Max Planck Society. </span></em></p><p class="fine-print"><em><span>Matthias Meyer receives funding from the Max Planck Society. </span></em></p><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>Zenobia Jacobs receives funding from the Australian Research Council. </span></em></p>Our research has also uncovered major long-term changes in ancient animal populations at Denisova Cave, and has provided the first direct evidence of Homo sapiens having lived there.Elena Zavala, PhD Student, Max Planck Institute for Evolutionary AnthropologyMatthias Meyer, Group Leader, Advanced DNA Sequencing Techniques Group, Max Planck Institute for Evolutionary AnthropologyRichard 'Bert' Roberts, Director, ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH), University of WollongongZenobia Jacobs, Professor, University of WollongongLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1575872021-03-23T22:36:46Z2021-03-23T22:36:46ZEvolutionary study suggests prehistoric human fossils ‘hiding in plain sight’ in Southeast Asia<figure><img src="https://images.theconversation.com/files/391289/original/file-20210323-13-1ietwc1.jpeg?ixlib=rb-1.1.0&rect=32%2C11%2C1918%2C1907&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Homo erectus skull from Java, Indonesia. This pioneering species stands at the root of a fascinating evolutionary tree.</span> <span class="attribution"><span class="source">Scimex</span></span></figcaption></figure><p>Island Southeast Asia has one of the largest and most intriguing hominin fossil records in the world. But our new research suggests there is another prehistoric human species waiting to be discovered in this region: a group called Denisovans, which have so far only been found thousands of kilometres away in caves in Siberia and the Tibetan Plateau.</p>
<p>Our study, published in <a href="https://www.nature.com/articles/s41559-021-01408-0">Nature Ecology and Evolution</a>, reveals genetic evidence that modern humans (<em>Homo sapiens</em>) interbred with Denisovans in this region, despite the fact Denisovan fossils have never been found here.</p>
<p>Conversely, we found no evidence that the ancestors of present-day Island Southeast Asia populations interbred with either of the two hominin species for which we <em>do</em> have fossil evidence in this region: <em>H. floresiensis</em> from Flores, Indonesia, and <em>H. luzonensis</em> from Luzon in the Philippines.</p>
<p>Together, this paints an intriguing — and still far from clear — picture of human evolutionary ancestry in Island Southeast Asia. We still don’t know the precise relationship between <em>H. floresiensis</em> and <em>H. luzonensis</em>, both of which were distinctively small-statured, and the rest of the hominin family tree. </p>
<p>And, perhaps more intriguingly still, our findings raise the possibility there are Denisovan fossils still waiting to be unearthed in Island Southeast Asia — or that we may already have found them but labelled them as something else.</p>
<h2>An ancient hominin melting pot</h2>
<p><a href="https://www.nationalgeographic.com/science/article/stone-tools-rhinoceros-luzon-philippines-ancient-hominins-science">Stone tool records</a> suggest that both <em>H. floresiensis</em> and <em>H. luzonensis</em> are descended from <em>Homo erectus</em> populations that colonised their respective island homes about 700,000 years ago. <em>H. erectus</em> is the first ancient human known to have ventured out of Africa, and has first arrived in Island Southeast Asia at least 1.6 million years ago.</p>
<p>This means the ancestors of <em>H. floresiensis</em> and <em>H. luzonensis</em> diverged from the ancestors of modern humans in Africa around two million years ago, before <em>H. erectus</em> set off on its travels. Modern humans spread out from Africa much more recently, probably arriving in Island Southeast Asia <a href="https://australian.museum/learn/science/human-evolution/the-first-modern-humans-in-southeast-asia/#">70,000-50,000 years ago</a>.</p>
<p>We already know that on their journey out of Africa about 70,000 years ago, <em>H. sapiens</em> met and interbred with other related hominin groups that had already colonised Eurasia.</p>
<p>The first of these encounters was with Neanderthals, and resulted in about 2% Neanderthal genetic ancestry in <a href="https://medlineplus.gov/genetics/understanding/dtcgenetictesting/neanderthaldna/#">today’s non-Africans</a>. </p>
<p>The other encounters involved Denisovans, a species that has been described solely from DNA analysis of a finger bone <a href="https://theconversation.com/fresh-clues-to-the-life-and-times-of-the-denisovans-a-little-known-ancient-group-of-humans-110504">found in Denisova Cave</a> in Siberia.</p>
<figure class="align-center ">
<img alt="Denisovan jaw fossil." src="https://images.theconversation.com/files/391154/original/file-20210323-13-qb8qta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/391154/original/file-20210323-13-qb8qta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=326&fit=crop&dpr=1 600w, https://images.theconversation.com/files/391154/original/file-20210323-13-qb8qta.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=326&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/391154/original/file-20210323-13-qb8qta.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=326&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/391154/original/file-20210323-13-qb8qta.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=409&fit=crop&dpr=1 754w, https://images.theconversation.com/files/391154/original/file-20210323-13-qb8qta.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=409&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/391154/original/file-20210323-13-qb8qta.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=409&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Only a handful of Denisovan fossils have been found, such as this jawbone unearthed in a Tibetan cave.</span>
<span class="attribution"><span class="source">Dongju Zhang/Wikimedia Commons</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Intriguingly, however, the largest amounts of Denisovan ancestry in today’s human populations are found in Island Southeast Asia and the former continent of Sahul (New Guinea and Australia). This is most likely the result of local interbreeding between Denisovans and modern humans — despite the lack of Denisovan fossils to back up this theory.</p>
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Read more:
<a href="https://theconversation.com/southeast-asia-was-crowded-with-archaic-human-groups-long-before-we-turned-up-119818">Southeast Asia was crowded with archaic human groups long before we turned up</a>
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<p>To learn more, we searched the genome sequences of more than 400 people alive today, including more than 200 from Island Southeast Asia, looking for distinct DNA sequences characteristic of these earlier hominin species.</p>
<p>We found genetic evidence the ancestors of present-day people living in Island Southeast Asia have interbred with Denisovans — just as many groups outside Africa have similarly interbred with Neanderthals during their evolutionary history. But we found no evidence of interbreeding with the more evolutionarily distant species <em>H. floresiensis</em> and <em>H. luzonensis</em> (or even <em>H. erectus</em>).</p>
<p>This is a remarkable result, as Island Southeast Asia is thousands of kilometres from Siberia, and contains one of the richest and most diverse hominin fossil records in the world. It suggests there are more fossil riches to be uncovered.</p>
<h2>So where are the region’s Denisovans?</h2>
<p>There are two exciting possibilities that might reconcile our genetic results with with the fossil evidence. First, it’s possible Denisovans mixed with <em>H. sapiens</em> in areas of Island Southeast Asia where hominin fossils are yet to be found.</p>
<p>One possible location is Sulawesi, where stone tools have been found dating back at least 200,000 years. Another is Australia, where 65,000-year-old artefacts currently attributed to modern humans were recently found at Madjebebe.</p>
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Read more:
<a href="https://theconversation.com/buried-tools-and-pigments-tell-a-new-history-of-humans-in-australia-for-65-000-years-81021">Buried tools and pigments tell a new history of humans in Australia for 65,000 years</a>
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<p>Alternatively, we may need to rethink our interpretation of the hominin fossils already discovered in Island Southeast Asia.</p>
<p>Confirmed Denisovan fossils are extremely rare and have so far only been found in central Asia. But perhaps Denisovans were much more diverse in size and shape than we realised, meaning we might conceivably have found them in Island Southeast Asia already but labelled them with a different name.</p>
<p>Given that the earliest evidence for hominin occupation of this region predates the divergence between modern humans and Denisovans, we can’t say for certain whether the region has been continuously occupied by hominins throughout this time. </p>
<p>It might therefore be possible that <em>H. floresiensis</em> and <em>H. luzonensis</em> (but also later forms of <em>H. erectus</em>) are much more closely related to modern humans than currently assumed, and might even be responsible for the Denisovan ancestry seen in today’s Island Southeast Asia human populations.</p>
<p>If that’s true, it would mean the mysterious Denisovans have been hiding in plain sight, disguised as <em>H. floresiensis</em>, <em>H. luzonensis</em> or <em>H. erectus</em>.</p>
<p>Solving these intriguing puzzles will mean waiting for future archaeological, DNA and proteomic (protein-related) studies to reveal more answers. But for now, the possibilities are fascinating.</p><img src="https://counter.theconversation.com/content/157587/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>João Teixeira receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Kristofer M. Helgen received funding from the Australian Research Council’s Centre for Australian Biodiversity and Heritage (CABAH).</span></em></p>The ancestors of modern-day people living on Southeast Asian islands likely interbred with a prehistoric species called Denisovans - raising the possibility of fresh and intriguing fossil discoveries.João Teixeira, Research associate, University of AdelaideKristofer M. Helgen, Chief Scientist and Director, Australian Museum Research Institute, Australian MuseumLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1489272020-11-08T19:06:12Z2020-11-08T19:06:12ZHow midnight digs at a holy Tibetan cave opened a window to prehistoric humans living on the roof of the world<figure><img src="https://images.theconversation.com/files/367394/original/file-20201104-15-194bmdj.jpg?ixlib=rb-1.1.0&rect=4%2C73%2C1435%2C1004&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Han Yuanyuan</span></span></figcaption></figure><p>A mountainside cave now used as a Tibetan Buddhist sanctuary was home to prehistoric humans known as <a href="https://theconversation.com/fresh-clues-to-the-life-and-times-of-the-denisovans-a-little-known-ancient-group-of-humans-110504">Denisovans</a> for tens of millennia. </p>
<p>Our painstaking efforts there are helping unravel the story of how early humans adapted to live in one of the world’s most remote and mountainous places. </p>
<p>Our research, <a href="https://science.sciencemag.org/content/370/6516/584">published in Science</a>, provides a better understanding of the little-known prehistoric humans who lived tens of thousands of years ago on the roof of the world.</p>
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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>
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<h2>Mountain retreat</h2>
<p>In 1980, half of a fossilised jawbone was found by a monk in the Baishiya Karst Cave in China’s Gansu province, in the northeastern part of the Tibetan Plateau. The jawbone’s long-deceased owner was dubbed “Xiahe Man”.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/367397/original/file-20201104-13-oedj8t.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Close-up of jawbone fossil" src="https://images.theconversation.com/files/367397/original/file-20201104-13-oedj8t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/367397/original/file-20201104-13-oedj8t.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=310&fit=crop&dpr=1 600w, https://images.theconversation.com/files/367397/original/file-20201104-13-oedj8t.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=310&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/367397/original/file-20201104-13-oedj8t.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=310&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/367397/original/file-20201104-13-oedj8t.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=389&fit=crop&dpr=1 754w, https://images.theconversation.com/files/367397/original/file-20201104-13-oedj8t.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=389&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/367397/original/file-20201104-13-oedj8t.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=389&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">This jawbone fragment represents the only known remains of the mysterious Xiahe Man.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p><a href="https://www.nature.com/articles/s41586-019-1139-x">Analysis</a> showed the mandible was actually the 160,000-year-old remains of a Denisovan. This group of mysterious prehistoric humans was originally discovered in the Denisova Cave in Siberia, Russia. </p>
<p>So this fossil was not only the earliest evidence of human occupation on the Tibetan Plateau, but also the first Denisovan fossil to be found outside of Denisova Cave — and the largest to ever be found. </p>
<p>However, without other archaeological evidence to put the solitary jawbone in context, this single fossil gave us little convincing evidence to piece together the full story of the mysterious Denisovans living on the roof of the world. </p>
<p>For this, we needed to properly excavate the Baishiya Karst Cave and see what we could find. After dozens of visits to the cave and others nearby, in 2016 we finally found the first indisputable stone artefacts (probably made by Denisovans) on the cave floor. </p>
<p>With this, we became further convinced the cave was a treasure trove of archaeological deposits that could help tell the story of the Denisovans. But, as it’s also a Buddhist holy cave, we weren’t allowed to dig inside it — not even one scrape of a trowel.</p>
<h2>Midnight digging in the depths of winter</h2>
<p>After two years of wrangling with authorities and extended negotiations with the temple’s Buddhist caretakers, we finally got permission to excavate a limited area within the cave. This was on the condition we worked late at night during the cold of winter, when no monks or tourists were visiting.</p>
<p>So every night, for three weeks, we inched our way across a frozen river, trudged up the mountainside through prickly branches and thick snow to reach the cave 3,280 metres above sea level. We slept during the day and excavated at night. </p>
<p>Despite the bone-chilling wind and darkness punctuated only by weak lamplight, it was exciting work. And our efforts were rewarded. </p>
<p>The archaeological remains we uncovered were richer and even more beautiful than we’d expected, including stone artefacts and animal bones buried throughout the sediments.</p>
<p>In 2019, a fresh permit allowed us to work during the day, too, albeit still in December (the coldest month of the Tibetan winter). We found yet more archaeological riches, including stone artefacts, animal bones and the remains of fires — crucial evidence of people living in the cave.</p>
<figure class="align-center ">
<img alt="Archaeologists dig in cave walls." src="https://images.theconversation.com/files/367380/original/file-20201104-13-11jnjfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/367380/original/file-20201104-13-11jnjfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/367380/original/file-20201104-13-11jnjfz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/367380/original/file-20201104-13-11jnjfz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/367380/original/file-20201104-13-11jnjfz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/367380/original/file-20201104-13-11jnjfz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/367380/original/file-20201104-13-11jnjfz.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">
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<span class="caption">Researchers sampling the Baishiya Karst Cave.</span>
<span class="attribution"><span class="source">Han Yuanyuan</span></span>
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</figure>
<h2>Crucial questions</h2>
<p>Our discoveries have raised several questions. Who lived in the cave and made these artefacts, and when? Were they Denisovans like the original Xiahe Man from 160,000 years ago, or modern humans? Or perhaps a genetic combination of both?</p>
<p>The “when” question was tackled using two techniques. By radiocarbon-dating the animal bones, we worked out when they were brought into the cave — either as food for human occupants, or simply animals sheltering alongside humans.</p>
<p>Our dating techniques, similar to those used previously at <a href="https://www.nature.com/articles/s41586-018-0843-2">Denisova Cave</a>, revealed the oldest stone artefacts in the Baishiya Karst Cave were buried more than 190,000 years ago. Since then, sediments and stone artefacts accumulated over time until at least 45,000 years ago, or perhaps more recently still. </p>
<h2>DNA identification</h2>
<p>But who were the people who lived there? To answer that question without any fresh human fossils besides the original jawbone, we needed to examine <a href="https://science.sciencemag.org/content/356/6338/605">human DNA in the sediment samples</a>.</p>
<p>We focused on identifying sequences of “<a href="https://www.nature.com/scitable/topicpage/mtdna-and-mitochondrial-diseases-903/">mitochondrial DNA</a>”, as cells contain many more copies of this than they do nuclear DNA. Thus, mitochondrial DNA is easier to obtain and analyse for research.</p>
<p>We found mitochondrial DNA matching Denisovans in cave sediments between 100,000–60,000 years old. What’s more, we found the newer samples were more closely related to those from Denisova Cave than older ones, indicating Denisovans were indeed more widespread than originally thought. </p>
<p>It’s possible they could have even contributed significantly to modern human DNA. For example, they may have helped today’s Tibetan Plateau dwellers on their evolutionary journey of adapting to high-altitude mountain life. </p>
<p>To confirm this, we’ll need to find out how long the Denisovans lived in the region around the Baishiya Karst Cave, and crucially, whether they survived long enough to intermingle with the modern humans who <a href="https://science.sciencemag.org/content/362/6418/1049">arrived on the Tibetan Plateau</a> between 40,000–30,000 years ago.</p>
<p>Although, even if Denisovans and modern humans did come face to face, they would have actually had to interbreed for Denisovans to be able to share their high-altitude evolutionary adaptations. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/explainer-what-are-mitochondria-and-how-did-we-come-to-have-them-83106">Explainer: what are mitochondria and how did we come to have them?</a>
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<p>It’s difficult to know whether this happened by only analysing mitochondrial DNA, since this only carries information about the maternal lineage.</p>
<p>This means it doesn’t always reflect the complete population history of a specimen. Future attempts to extract nuclear DNA from the Baishiya Karst Cave may finally provide the tools needed to explore these questions.</p><img src="https://counter.theconversation.com/content/148927/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bo Li receives funding from Australian Research Council. </span></em></p><p class="fine-print"><em><span>Dongju Zhang receives funding from the Natural Science Foundation of China.</span></em></p><p class="fine-print"><em><span>Qiaomei Fu receives funding from the Natural Science Foundation of China.</span></em></p><p class="fine-print"><em><span>Zenobia Jacobs receives funding from Australian Research Council.</span></em></p>Early humans called Denisovans lived in a remote mountain cave between 100,000 and 60,000 years ago, and possibly longer still, raising intriguing questions about their relationship to modern humans.Bo Li, Associate professor, University of WollongongDongju Zhang, Associate Professor, Institute of Tibetan Plateau Research, Chinese Academy of SciencesQiaomei Fu, Professor, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of SciencesZenobia Jacobs, Professor, University of WollongongLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1316992020-02-12T19:01:22Z2020-02-12T19:01:22ZEarly humans in Africa may have interbred with a mysterious, extinct species – new research<figure><img src="https://images.theconversation.com/files/315037/original/file-20200212-61941-1phkkjr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Homo rhodesiensis is an example of an archaic human. </span> <span class="attribution"><span class="source">wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>One of the more startling discoveries arising from <a href="https://www.nature.com/articles/nature12886">genomic sequencing of ancient hominin DNA</a> is the realisation that all humans outside Africa have traces of DNA in their genomes that do not belong to our own species.</p>
<p>The approximately six billion people on Earth whose recent ancestry is not from Africa will have inherited between 1% and 2% of their genome from our closest but now extinct relatives: <a href="https://theconversation.com/neanderthals-cared-for-each-other-and-survived-into-old-age-new-research-93110">the Neanderthals</a>. East Asians and Oceanians have also inherited a small amount of ancestry from the <a href="https://genographic.nationalgeographic.com/denisovan/">Denisovans</a>, another close relative of <em>Homo Sapiens</em>.</p>
<p>Now a new study, <a href="https://advances.sciencemag.org/content/6/7/eaax5097">published in Science Advances</a>, suggests that early humans living <em>inside</em> Africa may also have interbred with archaic hominims. These are extinct species that are related to <em>Homo sapiens</em>. </p>
<p>The interbreeding outside Africa happened after our <em>Homo sapiens</em> ancestors expanded out of Africa into new environments. It was there they had <a href="https://theconversation.com/jaw-bone-discovery-reveals-more-about-secret-sex-lives-of-neanderthals-and-early-humans-43656">sex with Neaderthals</a> and the related <a href="https://theconversation.com/how-breeding-with-an-ancient-human-species-gave-tibetans-their-head-for-heights-28818">Denisovans</a>.</p>
<p>This led to new discoveries. Early genetic studies of people from across the globe had previously <a href="https://www.nature.com/articles/325031a0">suggested that our current distribution</a> was the result of a single expansion out of Africa around 100,000 years ago. But the identification of Neanderthal and Denisovan ancestry in modern Eurasians complicated things.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/315048/original/file-20200212-61952-1ijzkgh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/315048/original/file-20200212-61952-1ijzkgh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/315048/original/file-20200212-61952-1ijzkgh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=328&fit=crop&dpr=1 600w, https://images.theconversation.com/files/315048/original/file-20200212-61952-1ijzkgh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=328&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/315048/original/file-20200212-61952-1ijzkgh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=328&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/315048/original/file-20200212-61952-1ijzkgh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=412&fit=crop&dpr=1 754w, https://images.theconversation.com/files/315048/original/file-20200212-61952-1ijzkgh.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=412&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/315048/original/file-20200212-61952-1ijzkgh.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=412&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Homo Sapiens versus Neanderthals.</span>
<span class="attribution"><span class="source">Wikipedia</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>We still think that most – anywhere between about <a href="https://www.nature.com/articles/s41559-019-0992-1">92% and 98.5%</a> – of the ancestry in people not living in Africa today does indeed derive from the out-of-Africa expansion. But we now know the remainder came from archaic species whose ancestors left Africa hundreds of thousands of years before that.</p>
<h2>What was happening inside Africa?</h2>
<p>Insights into interbreeding have been driven by the much greater availability of modern and ancient genomes from outside of Africa. That’s because the cold and dry environments of Eurasia are much better at preserving DNA that the wet heat of tropical Africa.</p>
<p>But our understanding of the relationship between ancient human ancestors within Africa, and their connection with archaic humans, is beginning to deepen. A 2017 <a href="https://doi.org/10.1016/j.cell.2017.08.049">study of ancient DNA from southern Africa</a> investigated 16 ancient genomes from people alive over the last 10,000 years. This showed that the history of African populations was complex. There <a href="https://www.nature.com/articles/s41586-020-1929-1">wasn’t just a single group</a> of humans around in Africa when they expanded out 100,000 years ago.</p>
<p>It’s a result that was supported earlier this year by a <a href="https://www.nature.com/articles/s41586-020-1929-1">paper examining ancient DNA from four individuals</a> from what is now Cameroon. Taken together, this research suggests there were geographically diverse groups in Africa well before the main expansion out of the continent. And many of these groups will have contributed to the ancestry of people alive in Africa today.</p>
<p>In addition, it now appears that there was potentially gene-flow into ancient African <em>Homo sapiens</em> populations from an archaic ancestor. One way in which this could happen is for people to expand out of Africa, have sex with Neanderthals, and then migrate back into Africa. Indeed, this has been demonstrated in one <a href="https://doi.org/10.1016/j.cell.2020.01.012">recent study</a>.</p>
<p>The new paper provides evidence that there may also have been gene-flow into the ancestors of West Africans directly from a mysterious archaic hominin. The researchers compared Neanderthal and Densiovan DNA with that from four contemporary populations from West Africa. Using some elegant mathematics, they then built a statistical model to explain the relationships between the archaic hominins and modern Africans. </p>
<p>Interestingly, they suggest that 6%-7% of the genomes of West Africans is archaic in origin. But this archaic ancestry wasn’t Neanderthal or Denisovan. Their model suggested the additional ancestry came from an archaic population for which we don’t currently have a genome.</p>
<p>This ghost population likely split from the ancestors of humans and Neanderthals between 360,000 and 1.02 million years ago. That was well before the gene-flow event that brought Neanderthal DNA back into West Africa around 43,000 years ago – although the value of this could be anywhere between 0 and 124,000 years ago.</p>
<p>These dates position this ghost species as something akin to a Neanderthal, but that presumably was present within Africa, during the last 100,000 years. An alternative explanation is that the archaic hominin was present outside of Africa and interbred with populations there before they migrated back in.</p>
<p>Despite a raft of analyses that show that this result is not an artefact of either their methodology or some other genetic process, the authors are cautious about this result. They call for further analysis of both contemporary and ancient DNA from diverse populations in Africa.</p>
<p>Nevertheless, this research contributes to the ever-growing cannon of research demonstrating the promiscuous, species-crossing and complicated behaviours of the ancestors of all of us.</p><img src="https://counter.theconversation.com/content/131699/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>George Busby receives funding from Wellcome, the Medical Research Council, Oxford University and The Royal Geographical Society. </span></em></p>Early humans in Africa may have interbred with a ghost population that likely split from the ancestors of humans and Neanderthals between 360,000 and 1.02 million years ago.George Busby, Senior Research Fellow in Translational Genomics, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1287432019-12-23T14:00:43Z2019-12-23T14:00:43ZArchaeological discoveries are happening faster than ever before, helping refine the human story<figure><img src="https://images.theconversation.com/files/308018/original/file-20191219-11896-dhp3e6.jpg?ixlib=rb-1.1.0&rect=4%2C4%2C3285%2C1808&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">20 years ago, who could predict how much more researchers would know today about the human past – let alone what they could learn from a thimble of dirt, a scrape of dental plaque, or satellites in space.</span> <span class="attribution"><span class="source">Manuel Domínguez-Rodrigo</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>In 1924, a 3-year-old child’s skull found in South Africa forever changed how people think about human origins. </p>
<p>The <a href="https://www.smithsonianmag.com/science-nature/how-africa-became-the-cradle-of-humankind-108875040/">Taung Child</a>, our first encounter with an ancient group of proto-humans or <a href="https://www.smithsonianmag.com/science-nature/whats-in-a-name-hominid-versus-hominin-216054/">hominins</a> called <a href="https://www.nature.com/scitable/knowledge/library/australopithecus-and-kin-145077614/">australopithecines</a>, was a turning point in the study of human evolution. This discovery shifted the focus of human origins research from Europe and Asia onto Africa, setting the stage for the last century of research on the continent and into its “<a href="https://www.maropeng.co.za/">Cradles</a> of <a href="https://www.ngorongorocrater.org/oldupai.html">Humankind</a>.” </p>
<p>Few people back then would’ve been able to predict what scientists know about evolution today, and now <a href="https://www.nytimes.com/2019/04/10/science/hominins-human-evolution.html">the pace of discovery is faster than ever</a>. Even since the turn of the 21st century, human origins textbooks have been rewritten over and over again. Just 20 years ago, no one could have imagined what scientists know two decades later about humanity’s deep past, let alone how much knowledge could be extracted from a thimble of dirt, a scrape of dental plaque or satellites in space.</p>
<h2>Human fossils are outgrowing the family tree</h2>
<p>In Africa, there are now <a href="https://www.nature.com/scitable/knowledge/library/the-earliest-hominins-sahelanthropus-orrorin-and-ardipithecus-67648286/">several fossil candidates for the earliest hominin</a> dated to between 5 and 7 million years ago, when we know <a href="https://theconversation.com/when-humans-split-from-the-apes-55104">humans likely split off from other Great Apes</a> based on differences in our DNA. </p>
<p>Although discovered in the 1990s, publication of the 4.4 million year old skeleton nicknamed “<a href="http://doi.org/10.1126/science.326.5960.1598-a">Ardi</a>” in 2009 <a href="https://www.scientificamerican.com/article/how-humanlike-was-ardi/">changed scientists’ views on how hominins began walking</a>. </p>
<p>Rounding out our new relatives are a few australopithecines, including <a href="https://theconversation.com/found-our-3m-year-old-forebear-who-lived-alongside-lucy-42444"><em>Australopithecus deryiremeda</em></a> and <a href="https://blogs.scientificamerican.com/observations/is-australopithecus-sediba-the-most-important-human-ancestor-discovery-ever/"><em>Australopithecus sediba</em></a>, as well as a <a href="https://theconversation.com/more-secrets-of-human-ancestry-emerge-from-south-african-caves-77352">potentially late-surviving species of early <em>Homo</em></a> that reignited debate about when humans first began <a href="https://www.sapiens.org/culture/hominin-burial/">burying their dead</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/308012/original/file-20191219-11909-obon37.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308012/original/file-20191219-11909-obon37.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308012/original/file-20191219-11909-obon37.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=451&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308012/original/file-20191219-11909-obon37.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=451&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308012/original/file-20191219-11909-obon37.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=451&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308012/original/file-20191219-11909-obon37.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=567&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308012/original/file-20191219-11909-obon37.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=567&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308012/original/file-20191219-11909-obon37.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=567&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Fossils like that of <em>Australopithecus sediba</em>, discovered in South Africa by a 9-year-old boy, are reshaping the human family tree.</span>
<span class="attribution"><span class="source">Photo by Brett Eloff. Courtesy Prof Berger and Wits University</span>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>Perspectives on our own species have also changed. Archaeologists previously thought <em>Homo sapiens</em> <a href="https://doi.org/10.1016/j.gde.2006.10.008">evolved in Africa around 200,000 years ago</a>, but <a href="https://www.vox.com/science-and-health/2017/6/7/15745714/nature-homo-sapien-remains-jebel-irhoud">the story has become more complicated</a>. <a href="https://www.sciencemag.org/news/2017/06/world-s-oldest-homo-sapiens-fossils-found-morocco">Fossils discovered in Morocco</a> have pushed that date back to 300,000 years ago, consistent with <a href="https://theconversation.com/ancient-dna-increases-the-genetic-time-depth-of-modern-humans-84716">ancient DNA evidence</a>. This <a href="https://www.sciencedaily.com/releases/2018/07/180711114544.htm">raises doubts that our species emerged in any single place</a>. </p>
<p>This century has also brought unexpected discoveries from Europe and Asia. From enigmatic <a href="https://theconversation.com/a-700-000-year-old-fossil-find-shows-the-hobbits-ancestors-were-even-smaller-60192">“hobbits” on the Indonesian island of Flores</a> to the <a href="https://theconversation.com/fresh-clues-to-the-life-and-times-of-the-denisovans-a-little-known-ancient-group-of-humans-110504">Denisovans</a> in Siberia, our ancestors may have encountered a <a href="https://theconversation.com/southeast-asia-was-crowded-with-archaic-human-groups-long-before-we-turned-up-119818">variety of other hominins when they spread out of Africa</a>. Just this year, researchers reported a <a href="https://doi.org/10.1038/d41586-019-01152-3">new species from the Philippines</a>.</p>
<p>Anthropologists are realizing that our <em>Homo sapiens</em> ancestors had <a href="https://www.nature.com/news/evidence-mounts-for-interbreeding-bonanza-in-ancient-human-species-1.19394">much more contact with other human species</a> than previously thought. Today, human evolution <a href="https://www.theguardian.com/science/2009/jan/21/charles-darwin-evolution-species-tree-life">looks less like Darwin’s tree</a> and more like a <a href="https://aeon.co/ideas/human-evolution-is-more-a-muddy-delta-than-a-branching-tree">muddy, braided stream</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307209/original/file-20191216-123998-1trhsoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/307209/original/file-20191216-123998-1trhsoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307209/original/file-20191216-123998-1trhsoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307209/original/file-20191216-123998-1trhsoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307209/original/file-20191216-123998-1trhsoy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307209/original/file-20191216-123998-1trhsoy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307209/original/file-20191216-123998-1trhsoy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307209/original/file-20191216-123998-1trhsoy.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">The rise of biomolecular archaeology means new opportunities for interdisciplinary collaboration among field- and lab-based scientists.</span>
<span class="attribution"><span class="source">Christina Warinner</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Ancient DNA reveals old relationships</h2>
<p>Many recent discoveries have been made possible by the <a href="https://www.discovermagazine.com/planet-earth/everything-worth-knowing-about-ancient-dna">new science of ancient DNA</a>. </p>
<p>Since scientists fully sequenced the <a href="https://www.nature.com/articles/nature08835">first ancient human genome</a> in 2010, data from <a href="http://www.frontlinegenomics.com/news/19758/1000-ancient-genomes-achieved/">thousands of individuals</a> have shed new insights on our species’ origins and early history.</p>
<p>One shocking discovery is that <a href="https://www.nationalgeographic.com/news/2013/10/131021-neanderthal-human-evolution-teeth/">although our lineages split up to 800,000 years ago</a>, modern humans and Neanderthals <a href="https://www.livescience.com/64189-neanderthals-and-humans-interbreeding.html">mated a number of times</a> during the last Ice Age. This is why many people today <a href="https://theconversation.com/paying-a-heavy-price-for-loving-the-neanderthals-67221">possess some Neanderthal DNA</a>.</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 were 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>
<p>Ancient DNA is how researchers first identified the <a href="https://www.sciencemag.org/news/2019/03/our-mysterious-cousins-denisovans-may-have-mated-modern-humans-recently-15000-years-ago">mysterious Denisovans</a>, who interbred with us <a href="https://www.nature.com/articles/d41586-018-06004-0">and Neanderthals</a>. And while most studies are still conducted on bones and teeth, it is now possible to extract ancient DNA from other sources like <a href="https://www.nature.com/news/ancient-human-genomes-plucked-from-cave-dirt-1.21910">cave dirt</a> and <a href="https://www.sciencemag.org/news/2019/12/nearly-6000-year-old-chewing-gum-reveals-life-ancient-girl">6,000-year-old chewing gum</a>.</p>
<p>Genetic methods are also reconstructing <a href="https://www.smithsonianmag.com/smart-news/no-wait-real-ava-bronze-age-woman-scottish-highlands-180970950/">individual</a> and <a href="https://www.sciencealert.com/this-5-000-year-old-grave-site-tells-a-tragic-tale-of-an-extended-family-s-murder">family relationships</a>, and connecting <a href="https://theconversation.com/kennewick-man-was-native-american-study-suggests-43503">ancient individuals to living peoples</a> to end <a href="https://www.discovermagazine.com/planet-earth/kennewick-mans-bones-reburied-settling-a-decades-long-debate">decadeslong debates</a>.</p>
<p>The applications go far beyond humans. Paleogenomics is yielding surprising discoveries about <a href="https://www.discovermagazine.com/planet-earth/ancient-dna-reveals-the-surprisingly-complex-origin-story-of-corn">plants</a> and <a href="https://www.nytimes.com/2016/01/19/science/the-big-search-to-find-out-where-dogs-come-from.html">animals</a> from <a href="https://doi.org/10.1016/j.tig.2019.02.006">ancient seeds and skeletons</a> hidden in the backrooms of museums. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307221/original/file-20191216-124036-13tvs7z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/307221/original/file-20191216-124036-13tvs7z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307221/original/file-20191216-124036-13tvs7z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307221/original/file-20191216-124036-13tvs7z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307221/original/file-20191216-124036-13tvs7z.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307221/original/file-20191216-124036-13tvs7z.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307221/original/file-20191216-124036-13tvs7z.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307221/original/file-20191216-124036-13tvs7z.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">Natural history museums hold a wealth of information, some of which can only be tapped through new biomolecular methods. Scientists analyze modern and fossil animal skeletons to ask questions about the past using ancient proteins.</span>
<span class="attribution"><span class="source">Mary Prendergast at National Museums of Kenya</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Biomolecules are making the invisible visible</h2>
<p>DNA is not the only molecule revolutionizing studies of the past. </p>
<p><a href="https://www.the-scientist.com/features/paleoproteomics-opens-a-window-into-the-past-30026">Paleoproteomics</a>, the study of <a href="https://www.discovermagazine.com/planet-earth/paleoproteomics-lets-researchers-study-the-past-anew">ancient proteins</a>, can <a href="https://www.nature.com/articles/d41586-019-01986-x">determine the species of a fossil</a> and recently linked a <a href="https://phys.org/news/2019-11-extinct-giant-ape-linked-orangutan.html">9-foot tall, 1,300-pound extinct ape</a> that lived nearly 2 million years ago to today’s orangutans.</p>
<p>Dental calculus – the hardened plaque that your dentist scrapes off your teeth – is particularly informative, revealing everything from <a href="https://www.bbc.com/news/science-environment-49650806">who was drinking milk 6,000 years ago</a> to the surprising <a href="https://theconversation.com/the-daily-life-of-a-neanderthal-revealed-from-the-gunk-in-their-teeth-73959">diversity of plants</a>, some <a href="https://www.sciencedaily.com/releases/2017/03/170308131218.htm">likely medicinal</a>, in Neanderthal diets. Calculus can help scientists understand <a href="https://www.theverge.com/2014/3/3/5465942/dental-plaque-preserves-bacteria-diet-1000-year-old-skeletons">ancient diseases</a> and how the human <a href="https://www.discovermagazine.com/planet-earth/uncovering-our-ancestral-microbiomes">gut microbiome has changed over time</a>. Researchers even find cultural clues – <a href="https://theconversation.com/we-found-lapis-lazuli-hidden-in-ancient-teeth-revealing-the-forgotten-role-of-women-in-medieval-arts-109458">bright blue lapis lazuli</a> trapped in a medieval nun’s calculus led historians to reconsider who penned illuminated manuscripts.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307207/original/file-20191216-123987-1q3l38p.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/307207/original/file-20191216-123987-1q3l38p.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307207/original/file-20191216-123987-1q3l38p.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=513&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307207/original/file-20191216-123987-1q3l38p.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=513&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307207/original/file-20191216-123987-1q3l38p.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=513&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307207/original/file-20191216-123987-1q3l38p.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=645&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307207/original/file-20191216-123987-1q3l38p.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=645&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307207/original/file-20191216-123987-1q3l38p.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=645&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Scientists unexpectedly found lazurite pigment in calcified plaque clinging to a 11th- to 12th-century woman’s tooth, challenging the assumption that male monks were the primary makers of medieval manuscripts.</span>
<span class="attribution"><span class="source">Christina Warinner</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Lipid residues trapped in pottery have revealed the <a href="https://www.wnycstudios.org/podcasts/takeaway/segments/217810-african-pottery-gives-hints-earliest-dairy-farmers">origins of milk consumption in the Sahara</a> and showed that oddly shaped pots found throughout Bronze and Iron Age Europe were <a href="https://theconversation.com/discovery-of-prehistoric-baby-bottles-shows-infants-were-fed-cows-milk-5-000-years-ago-124115">ancient baby bottles</a>. </p>
<p>Researchers use <a href="https://www.wired.com/beyond-the-beyond/2018/08/lab-zooarchaeology-mass-spectrometry/">collagen-based “barcodes”</a> of different animal species to answer questions ranging from when <a href="https://www.eurekalert.org/pub_releases/2017-08/mpif-eio081717.php">Asian rats arrived as castaways on Africa-bound ships</a> to what <a href="https://www.theatlantic.com/science/archive/2019/02/dna-books-artifacts/582814/">animals were used to produce medieval parchment</a> or even to detect <a href="https://www.sciencemag.org/news/2017/07/goats-bookworms-monk-s-kiss-biologists-reveal-hidden-history-ancient-gospels">microbes left by a monk’s kiss</a> on a page.</p>
<h2>Big data is revealing big patterns</h2>
<p>While biomolecules help researchers zoom into microscopic detail, other approaches let them zoom out. Archaeologists have used <a href="https://www.sciencemag.org/news/2019/04/declassified-u-2-spy-plane-photos-are-boon-aerial-archaeology">aerial photography</a> since the 1930s, but widely available <a href="https://www.discovermagazine.com/the-sciences/how-google-earth-has-revolutionized-archaeology">satellite imagery</a> now enables researchers to <a href="https://www.scientificamerican.com/article/satellites-expose-8000-years-lost-civilization/">discover new sites</a> and <a href="https://doi.org/10.1371/journal.pone.0188589">monitor existing ones at risk</a>. Drones flying over sites help <a href="https://www.wired.com/story/archaeologists-dont-always-need-to-digtheyve-got-drones/">investigate how and why they were made</a> and <a href="https://www.nationalgeographic.com/news/2014/4/140411-drones-jordan-dead-sea-looting-archaeology/">combat looting</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307923/original/file-20191219-11891-t26lov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/307923/original/file-20191219-11891-t26lov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307923/original/file-20191219-11891-t26lov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=369&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307923/original/file-20191219-11891-t26lov.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=369&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307923/original/file-20191219-11891-t26lov.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=369&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307923/original/file-20191219-11891-t26lov.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=464&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307923/original/file-20191219-11891-t26lov.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=464&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307923/original/file-20191219-11891-t26lov.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=464&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 increasingly use technology to understand how sites fit into their environment and to document sites at risk. Here, a drone captured a tell (a mound indicating build-up of ancient settlements) in the Kurdistan Region of Iraq.</span>
<span class="attribution"><span class="source">Jason Ur</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Originally developed for space applications, scientists now use <a href="https://theconversation.com/meet-lidar-the-amazing-laser-technology-thats-helping-archaeologists-discover-lost-cities-60915">LIDAR</a> – a remote sensing technique that uses lasers to measure distance – to map 3D surfaces and visualize landscapes here on Earth. As a result, ancient cities are emerging from dense vegetation in places like <a href="https://www.nytimes.com/2019/10/08/science/archaeology-lidar-maya.html">Mexico</a>, <a href="https://www.smithsonianmag.com/smart-news/laser-scans-reveal-massive-khmer-cities-hidden-cambodian-jungle-180959395/">Cambodia</a> and <a href="https://theconversation.com/how-we-recreated-a-lost-african-city-with-laser-technology-92852">South Africa</a>.</p>
<p>Technologies that can peer underground from the surface, such as <a href="https://theconversation.com/ice-age-footprints-of-mammoths-and-prehistoric-humans-revealed-for-the-first-time-using-radar-126696">Ground Penetrating Radar</a>, are also revolutionizing the field – for example, <a href="https://www.nationalgeographic.com/news/2014/9/140911-stonehenge-map-underground-monument-radar/">revealing previously unknown structures at Stonehenge</a>. More and more, archaeologists are able to do their work <a href="https://theconversation.com/why-archaeology-is-so-much-more-than-just-digging-108679">without even digging a hole</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307212/original/file-20191216-123992-1dzh788.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/307212/original/file-20191216-123992-1dzh788.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307212/original/file-20191216-123992-1dzh788.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307212/original/file-20191216-123992-1dzh788.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307212/original/file-20191216-123992-1dzh788.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307212/original/file-20191216-123992-1dzh788.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307212/original/file-20191216-123992-1dzh788.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307212/original/file-20191216-123992-1dzh788.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">Geophysical survey methods enable archaeologists to detect buried features without digging large holes, maximizing knowledge while minimizing destruction.</span>
<span class="attribution"><span class="source">Mary Prendergast and Thomas Fitton</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Teams of archaeologists are <a href="https://www.universiteitleiden.nl/en/news/2017/01/from-scarcity-to-abundance-big-data-in-archaeology">combining big datasets</a> in new ways to understand large-scale processes. In 2019, over 250 archaeologists pooled their findings to show that <a href="https://theconversation.com/surveying-archaeologists-across-the-globe-reveals-deeper-and-more-widespread-roots-of-the-human-age-the-anthropocene-122008">humans have altered the planet for thousands of years</a>, for example, with a <a href="https://gbtimes.com/ancient-chinese-irrigation-systems-added-to-world-heritage-list">2,000-year-old irrigation system</a> in China. This echoes <a href="https://www.smithsonianmag.com/smithsonian-institution/new-research-shows-late-pleistocene-humans-transforming-habitats-180959324/">other studies</a> <a href="https://doi.org/10.1073/pnas.1908179116">that challenge</a> the idea that the Anthropocene, the current period defined by human influences on the planet, <a href="https://www.theguardian.com/environment/2016/aug/29/declare-anthropocene-epoch-experts-urge-geological-congress-human-impact-earth">only began in the 20th century</a>.</p>
<h2>New connections are raising new possibilities</h2>
<p>These advances bring researchers together in exciting new ways. Over <a href="https://www.sciencealert.com/over-140-mysterious-geoglyphs-discovered-within-the-ancient-nazca-lines">140 new Nazca Lines</a>, ancient images carved into a Peruvian desert, were discovered using artificial intelligence to sift through drone and satellite imagery. With the wealth of high-resolution satellite imagery online, teams are also turning to <a href="https://www.wired.com/2017/01/want-space-archaeologist-heres-chance/">crowdsourcing</a> to find new archaeological sites.</p>
<p>Although new partnerships among archaeologists and scientific specialists <a href="https://theconversation.com/ancient-dna-is-a-powerful-tool-for-studying-the-past-when-archaeologists-and-geneticists-work-together-111127">are not always tension-free</a>, there is growing consensus that studying the past means reaching across fields.</p>
<p>The <a href="http://www.unesco.org/new/en/communication-and-information/portals-and-platforms/goap/open-science-movement/">Open Science movement</a> aims to makes this work accessible to all. <a href="https://www.nature.com/articles/s41467-018-05227-z">Scientists</a> including <a href="http://www.openaccessarchaeology.org/">archaeologists</a> are sharing data more freely within and beyond the academy. <a href="https://www.saa.org/education-outreach/public-outreach/what-is-public-archaeology">Public archaeology</a> programs, <a href="https://theconversation.com/how-community-digs-can-inspire-the-next-generation-of-archaeologists-70352">community digs</a> and <a href="https://theconversation.com/a-digital-archaeologist-helps-inaccessible-collections-be-seen-123672">digital museum collections</a> are becoming common. You can even print your own copy of famous fossils from <a href="https://www.forbes.com/sites/kristinakillgrove/2015/09/19/how-to-print-your-own-3d-replicas-of-homo-naledi-and-other-hominin-fossils/#48db66c512c0">freely available 3D scans</a>, or an <a href="http://christinawarinner.com/outreach/children/adventures-in-archaeological-science/">archaeological coloring book</a> in more than 30 languages.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/307983/original/file-20191219-11946-1kkh5ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/307983/original/file-20191219-11946-1kkh5ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/307983/original/file-20191219-11946-1kkh5ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/307983/original/file-20191219-11946-1kkh5ns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/307983/original/file-20191219-11946-1kkh5ns.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/307983/original/file-20191219-11946-1kkh5ns.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/307983/original/file-20191219-11946-1kkh5ns.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/307983/original/file-20191219-11946-1kkh5ns.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">Archaeologists are increasingly reaching out to communities to share their findings, for example at this school presentation in Tanzania.</span>
<span class="attribution"><span class="source">Agness Gidna</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Efforts to make <a href="https://www.cbc.ca/news/canada/british-columbia/a-voice-to-confront-one-woman-s-journey-to-decolonize-archeology-1.5137875">archaeology</a> and <a href="https://phys.org/news/2019-12-d-museums-repatriation-decolonization-efforts.html">museums</a> more equitable and engage <a href="https://www.crowcanyon.org/index.php/what-is-indigenous-archaeology-and-what-does-it-mean-for-crow-canyon">indigenous research partners</a> are gaining momentum as archaeologists consider <a href="https://science.sciencemag.org/content/360/6387/384">whose past is being revealed</a>. Telling the human story requires a community of voices to do things right.</p>
<h2>Studying the past to change our present</h2>
<p>As new methods enable profound insight into humanity’s shared history, a challenge is to ensure that these insights are relevant and beneficial in the present and future. </p>
<p>In a year marked by <a href="https://time.com/person-of-the-year-2019-greta-thunberg/">youth-led climate strikes</a> and <a href="https://blogs.scientificamerican.com/observations/a-scary-year-for-climate-change/">heightened awareness of a planet in crisis</a>, it may seem counterproductive to look back in time. </p>
<p>Yet in so doing, archaeologists are providing <a href="https://theconversation.com/using-archaeology-to-understand-the-past-present-future-of-climate-change-108668">empirical support for climate change</a> and revealing how ancient peoples coped with challenging environments. </p>
<p>As one example, studies show that while industrial meat production has <a href="https://www.smithsonianmag.com/science-nature/beef-uses-ten-times-more-resources-poultry-dairy-eggs-pork-180952103/">serious environmental costs</a>, <a href="https://www.britannica.com/topic/transhumance">transhumance</a> – a traditional practice of seasonally moving livestock, now <a href="https://www.euromontana.org/en/transhumance-as-unesco-intangible-cultural-heritage/">recognized by UNESCO as intangible cultural heritage</a> – is not only <a href="https://www.iucn.org/content/pastoralism-provides-crucial-services-humanity-can-support-green-economy-transition">light on the land</a> today, but helped promote <a href="https://natureecoevocommunity.nature.com/users/175450-fiona-marshall/posts/38272-ancient-herders-enriched-and-restructured-african-grasslands">biodiversity and healthy landscapes</a> in the past.</p>
<p>Archaeologists today are contributing their methods, data and perspectives toward a vision for a less damaged, more just planet. While it’s difficult to predict exactly what the next century holds in terms of archaeological discoveries, a new focus on “<a href="https://doi.org/10.1007/s10437-019-09347-9">usable pasts</a>” points in a positive direction.</p>
<p>[ <em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters/weekly-highlights-61?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=weeklysmart">You can get our highlights each weekend</a>. ]</p><img src="https://counter.theconversation.com/content/128743/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>20 years ago, who could predict how much more researchers would know today about the human past – let alone what they could learn from a thimble of dirt, a scrape of dental plaque, or satellites in space.Elizabeth Sawchuk, Postdoctoral Fellow and Research Assistant Professor of Anthropology, Stony Brook University (The State University of New York)Mary Prendergast, Professor of Anthropology, Saint Louis University – MadridLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1266382019-11-21T15:33:10Z2019-11-21T15:33:10ZWere other humans the first victims of the sixth mass extinction?<figure><img src="https://images.theconversation.com/files/302005/original/file-20191115-66945-1ccxz9v.jpg?ixlib=rb-1.1.0&rect=5%2C291%2C830%2C485&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A Neanderthal skull shows head trauma, evidence of ancient violence</span> <span class="attribution"><a class="source" href="http://humanorigins.si.edu/evidence/human-fossils/fossils/saint-c%C3%A9saire">Smithsonian National Museum of Natural History</a></span></figcaption></figure><p>Nine human species walked the Earth 300,000 years ago. Now there is just one. The Neanderthals, <em>Homo neanderthalensis</em>, were <a href="https://theconversation.com/why-the-neanderthals-may-have-been-more-sophisticated-hunters-than-we-thought-new-study-98870">stocky hunters</a> adapted to Europe’s cold steppes. The related <a href="https://theconversation.com/fresh-clues-to-the-life-and-times-of-the-denisovans-a-little-known-ancient-group-of-humans-110504">Denisovans</a> inhabited Asia, while the more primitive <a href="https://theconversation.com/a-snapshot-of-our-mysterious-ancestor-homo-erectus-101122"><em>Homo erectus</em></a> lived in Indonesia, and <a href="https://www.nature.com/articles/108371a0.pdf"><em>Homo rhodesiensis</em></a> in central Africa. </p>
<p>Several short, small-brained species survived alongside them: <a href="https://theconversation.com/homo-naledi-fossil-discovery-a-triumph-for-open-access-and-education-47726"><em>Homo naledi</em></a> in South Africa, <a href="https://theconversation.com/how-much-evidence-is-enough-to-declare-a-new-species-of-human-from-a-philippines-cave-site-115139"><em>Homo luzonensis</em></a> in the Philippines, <a href="https://theconversation.com/fast-evolution-explains-the-tiny-stature-of-extinct-hobbit-from-flores-island-124747"><em>Homo floresiensis</em></a> (“hobbits”) in Indonesia, and the mysterious <a href="https://theconversation.com/bone-suggests-red-deer-cave-people-a-mysterious-species-of-human-52437">Red Deer Cave People</a> in China. Given how quickly we’re discovering new species, more are likely waiting to be found.</p>
<p>By 10,000 years ago, they were all gone. The disappearance of these other species resembles a mass extinction. But there’s no obvious environmental catastrophe – volcanic eruptions, climate change, asteroid impact – driving it. Instead, the extinctions’ timing suggests they were caused by the spread of a new species, evolving <a href="https://science.sciencemag.org/content/358/6363/652.abstract">260,000-350,000 years ago</a> in <a href="https://www.nature.com/articles/s41586-019-1714-1">Southern Africa</a>: <em>Homo sapiens</em>. </p>
<p>The spread of modern humans out of Africa has caused a <a href="https://www.theguardian.com/environment/2017/jul/10/earths-sixth-mass-extinction-event-already-underway-scientists-warn">sixth mass extinction</a>, a greater than 40,000-year event extending from the disappearance of Ice Age mammals to the destruction of rainforests by civilisation today. But were other humans the first casualties? </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/302000/original/file-20191115-66925-p0qco1.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/302000/original/file-20191115-66925-p0qco1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/302000/original/file-20191115-66925-p0qco1.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=398&fit=crop&dpr=1 600w, https://images.theconversation.com/files/302000/original/file-20191115-66925-p0qco1.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=398&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/302000/original/file-20191115-66925-p0qco1.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=398&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/302000/original/file-20191115-66925-p0qco1.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=500&fit=crop&dpr=1 754w, https://images.theconversation.com/files/302000/original/file-20191115-66925-p0qco1.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=500&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/302000/original/file-20191115-66925-p0qco1.png?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"></a>
<figcaption>
<span class="caption">Human evolution.</span>
<span class="attribution"><span class="source">Nick Longrich</span></span>
</figcaption>
</figure>
<p>We are a uniquely dangerous species. We hunted <a href="https://www.amazon.com/Quaternary-Extinctions-Prehistoric-Paul-Martin/dp/0816511004/ref=sr_1_3?keywords=prehistoric+extinctions+martin&qid=1573645985&sr=8-3">wooly mammoths, ground sloths</a> and <a href="https://science.sciencemag.org/content/287/5461/2250.full?_ga=2.156387641.382776719.1573642705-28080894.1573476299">moas</a> to extinction. We destroyed plains and forests for farming, modifying over <a href="https://www.geosociety.org/gsatoday/archive/22/12/article/i1052-5173-22-12-4.htm">half the planet’s land area</a>. We altered the planet’s climate. But we are most dangerous to other human populations, because we compete for resources and land.</p>
<p>History is full of examples of people warring, displacing and wiping out other groups over territory, from Rome’s destruction of Carthage, to the American conquest of the West and the British colonisation of Australia. There have also been recent genocides and ethnic cleansing in <a href="https://theconversation.com/remembering-srebrenica-more-than-20-years-on-99122">Bosnia</a>, Rwanda, <a href="https://theconversation.com/islamic-states-genocidal-crimes-demand-justice-how-can-it-be-done-97646">Iraq</a>, Darfur and <a href="https://theconversation.com/rohingya-crisis-this-is-what-genocide-looks-like-83924">Myanmar</a>. Like language or tool use, a capacity for and tendency to engage in genocide is arguably an intrinsic, <a href="https://www.amazon.com/Third-Chimpanzee-Evolution-Future-Animal/dp/0060845503/ref=sr_1_1?keywords=the+third+chimpanzee&qid=1573645399&sr=8-1">instinctive part of human nature</a>. There’s little reason to think that early <em>Homo sapiens</em> were less territorial, less violent, less intolerant – less human.</p>
<p>Optimists have painted early hunter-gatherers as peaceful, <a href="https://theconversation.com/explainer-the-myth-of-the-noble-savage-55316">noble savages</a>, and have argued that our culture, not our nature, creates violence. But field studies, historical accounts, and archaeology <a href="https://www.amazon.com/Constant-Battles-Why-We-Fight/dp/0312310900/ref=sr_1_1?keywords=constant+battles&qid=1573829278&sr=8-1">all show</a> that war in <a href="https://www.amazon.com/War-Before-Civilization-Peaceful-Savage/dp/0195119126">primitive cultures was intense, pervasive and lethal</a>. Neolithic weapons such as clubs, spears, axes and bows, combined with guerrilla tactics like raids and ambushes, were devastatingly effective. Violence was the leading cause of death among men in these societies, and wars saw higher casualty levels per person than World Wars I and II. </p>
<p>Old bones and artefacts show this violence is ancient. The 9,000-year-old Kennewick Man, from North America, has a spear point embedded in his pelvis. The 10,000-year-old <a href="https://www.nature.com/articles/nature16477">Nataruk site</a> in Kenya documents the brutal massacre of at least 27 men, women, and children. </p>
<p>It’s unlikely that the other human species were much more peaceful. The existence of <a href="https://www.nature.com/articles/nature13727">cooperative violence in male chimps</a> suggests that war predates the evolution of humans. Neanderthal skeletons show <a href="https://www.nature.com/articles/s41586-018-0696-8">patterns</a> of <a href="https://www.pnas.org/content/99/9/6444.short">trauma</a> consistent with warfare. But sophisticated weapons likely gave <em>Homo sapiens</em> a military <a href="http://www.paleoanthro.org/media/journal/content/PA20100100.pdf">advantage</a>. The arsenal of early <em>Homo sapiens</em> probably included <a href="https://www.sciencedirect.com/science/article/pii/S030544030500230X">projectile weapons</a> like javelins and <a href="http://digitallibrary.amnh.org/bitstream/handle/2246/2613/N2403.pdf?sequence=1">spear-throwers</a>, throwing sticks and <a href="https://www.nature.com/articles/nature16477">clubs</a>.</p>
<p>Complex tools and culture would also have helped us efficiently harvest a wider range of animals and plants, feeding larger tribes, and giving our species a strategic advantage in numbers.</p>
<h2>The ultimate weapon</h2>
<p>But cave <a href="https://theconversation.com/borneo-cave-discovery-is-the-worlds-oldest-rock-art-in-southeast-asia-106252?fbclid=IwAR38kVzZ5Pa1zSZH7ZGWz1jFwJBRt_m035lvW-H6coqc8evaHWD1Ba6HisI">paintings</a>, <a href="https://www.nature.com/articles/nature07995">carvings</a>, and <a href="https://www.nature.com/articles/nature08169">musical instruments</a> hint at something far more dangerous: a sophisticated capacity for abstract thought and communication. The ability to cooperate, plan, <a href="https://www.amazon.com/War-Carl-von-Clausewitz-ebook/dp/B005R9EB68/ref=sr_1_1?keywords=clausewitz+on+war&qid=1573644303&s=digital-text&sr=1-1">strategise</a>, <a href="http://www.gutenberg.org/ebooks/1232">manipulate</a> and <a href="https://www.amazon.com/Art-War-Sun-Tzu-ebook/dp/B07YRX3MBM/ref=sr_1_2?keywords=sun+tzu+giles&qid=1573644250&s=digital-text&sr=1-2">deceive</a> may have been our ultimate weapon.</p>
<p>The incompleteness of the fossil record makes it hard to test these ideas. But in Europe, the only place with a relatively complete archaeological record, fossils show that within <a href="https://www.nature.com/articles/nature13621">a few thousand years</a> of our arrival , Neanderthals vanished. Traces of <a href="https://science.sciencemag.org/content/328/5979/710/tab-pdf">Neanderthal DNA in some Eurasian people</a> prove we didn’t just replace them after they went extinct. We met, and we mated.</p>
<p>Elsewhere, DNA tells of other encounters with archaic humans. East Asian, Polynesian and Australian groups have <a href="https://www.nature.com/articles/nature09710">DNA</a> from <a href="https://www.cell.com/cell/fulltext/S0092-8674(19)30218-1">Denisovans</a>. DNA from <a href="https://www.nature.com/articles/ng.3621#ref23">another species</a>, possibly <em>Homo erectus</em>, occurs in many Asian people. African genomes <a href="https://www.pnas.org/content/108/37/15123">show traces of DNA</a> from yet another <a href="https://www.sciencedirect.com/science/article/pii/S0092867412008318">archaic species</a>. The fact that we interbred with these other species proves that they disappeared only after encountering us. </p>
<p>But why would our ancestors wipe out their relatives, causing a mass extinction – or, perhaps more accurately, a mass genocide?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/301300/original/file-20191112-178506-5fhhk2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/301300/original/file-20191112-178506-5fhhk2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=639&fit=crop&dpr=1 600w, https://images.theconversation.com/files/301300/original/file-20191112-178506-5fhhk2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=639&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/301300/original/file-20191112-178506-5fhhk2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=639&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/301300/original/file-20191112-178506-5fhhk2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=803&fit=crop&dpr=1 754w, https://images.theconversation.com/files/301300/original/file-20191112-178506-5fhhk2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=803&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/301300/original/file-20191112-178506-5fhhk2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=803&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">13,000-year-old spear points from Colorado.</span>
<span class="attribution"><span class="source">Chip Clark, Smithsonian Institution</span></span>
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</figure>
<p>The answer lies in <a href="https://www.amazon.com/Constant-Battles-Why-We-Fight/dp/0312310900/ref=sr_1_1?keywords=constant+battles&qid=1573829278&sr=8-1">population growth</a>. Humans reproduce exponentially, like all species. Unchecked, we historically <a href="http://www.gutenberg.org/ebooks/4239">doubled our numbers every 25 years</a>. And once humans became cooperative hunters, we had no predators. Without predation controlling our numbers, and little family planning beyond <a href="http://www.gutenberg.org/ebooks/4239">delayed marriage</a> and <a href="https://www.annualreviews.org/doi/pdf/10.1146/annurev.es.06.110175.000543">infanticide</a>, populations grew to exploit the available resources.</p>
<p>Further growth, or food shortages caused by drought, harsh winters or overharvesting resources <a href="https://www.amazon.com/Constant-Battles-Why-We-Fight/dp/0312310900/ref=sr_1_1?keywords=constant+battles&qid=1573829278&sr=8-1">would inevitably lead tribes into conflict</a> over food and foraging territory. Warfare became a check on population growth, perhaps the most important one.</p>
<p>Our elimination of other species probably wasn’t a planned, coordinated effort of the sort practised by civilisations, but a war of attrition. The end result, however, was just as final. Raid by raid, ambush by ambush, valley by valley, modern humans would have worn down their enemies and taken their land. </p>
<p>Yet the extinction of Neanderthals, at least, took a long time – thousands of years. This was partly because early <em>Homo sapiens</em> lacked the advantages of later conquering civilisations: <a href="https://www.amazon.com/Third-Chimpanzee-Evolution-Future-Animal/dp/0060845503/ref=sr_1_1?keywords=the+third+chimpanzee&qid=1573645399&sr=8-1">large numbers, supported by farming</a>, and <a href="https://www.amazon.com/Plagues-Peoples-William-McNeill-ebook/dp/B0047747QK/ref=sr_1_1?keywords=plagues+and+peoples&qid=1573645434&sr=8-1">epidemic diseases like smallpox, flu, and measles</a> that <a href="https://theconversation.com/european-colonisation-of-the-americas-killed-10-of-world-population-and-caused-global-cooling-110549">devastated their opponents</a>. But while Neanderthals lost the war, to hold on so long they must have fought and won many battles against us, suggesting a level of intelligence close to our own.</p>
<p>Today we look up at the stars and wonder if we’re <a href="https://theconversation.com/evolution-tells-us-we-might-be-the-only-intelligent-life-in-the-universe-124706">alone in the universe</a>. In <a href="https://www.amazon.com/Hobbit-Lord-Rings-Fellowship-Towers/dp/0345538374/ref=sr_1_2?keywords=the+lord+of+the+rings&qid=1573645527&sr=8-2">fantasy</a> and <a href="https://www.imdb.com/title/tt0060028/">science fiction</a>, we wonder what it might be like to meet other intelligent species, like us, but not us. It’s profoundly sad to think that we once did, and now, because of it, they’re gone.</p><img src="https://counter.theconversation.com/content/126638/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Nicholas R. Longrich 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>300,000 years ago, there were lots of different species of human. Now it’s only us – and we’re probably the reason why.Nicholas R. Longrich, Senior Lecturer, Paleontology and Evolutionary Biology, University of BathLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1224582019-09-26T09:03:12Z2019-09-26T09:03:12ZDishing the dirt: sediments reveal a famous early human cave site was also home to hyenas and wolves<figure><img src="https://images.theconversation.com/files/292356/original/file-20190913-35596-16zhd63.JPG?ixlib=rb-1.1.0&rect=24%2C57%2C3187%2C2074&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Sampling sediments in Denisova Cave.</span> <span class="attribution"><span class="license">Author provided</span></span></figcaption></figure><p>Denisova Cave in Siberia’s Altai Mountains is one of the world’s most important archaeological sites. It is famous for preserving evidence of three early human groups: Neanderthals, early <em>Homo sapiens</em>, and a third group known as the <a href="https://theconversation.com/fresh-clues-to-the-life-and-times-of-the-denisovans-a-little-known-ancient-group-of-humans-110504">Denisovans</a>. </p>
<p>Fossil bones, stone tools and ancient DNA gathered from the cave have told a story that is extremely significant for understanding the early chapters of human evolution in Asia, going back 300,000 years.</p>
<p>But our <a href="https://www.nature.com/articles/s41598-019-49930-3">new analysis</a> of the cave’s dirt floor reveals that it was also frequented by hyenas, wolves, and even bears for much of its history.</p>
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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>
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<p>Our research, carried out with Russian colleagues and <a href="https://www.nature.com/articles/s41598-019-49930-3">published today in Scientific Reports</a>, takes the story of the cave’s occupation down to the microscopic level – examining the dirt from the cave to piece together new evidence that is invisible to the naked eye.</p>
<p>We found that the sediments contain abundant fossil droppings, but surprisingly scant evidence of human activity such as fires.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/292367/original/file-20190913-35624-1bh38gx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/292367/original/file-20190913-35624-1bh38gx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/292367/original/file-20190913-35624-1bh38gx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/292367/original/file-20190913-35624-1bh38gx.JPG?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/292367/original/file-20190913-35624-1bh38gx.JPG?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/292367/original/file-20190913-35624-1bh38gx.JPG?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/292367/original/file-20190913-35624-1bh38gx.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">
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<span class="caption">The foothills of the Altai Mountains in the area of Denisova Cave.</span>
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<h2>Digging deeper</h2>
<p>The Denisova Cave fossils have already told us some remarkable tales about the cave’s past, and the now-extinct cousins of our own species that sought shelter there. DNA analysis of one bone fragment showed that it belonged to the <a href="https://theconversation.com/ancient-teenager-the-first-known-person-with-parents-of-two-different-species-101965">teenage daughter of a Neanderthal mother and a Denisovan father</a>.</p>
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Read more:
<a href="https://theconversation.com/ancient-teenager-the-first-known-person-with-parents-of-two-different-species-101965">Ancient teenager the first known person with parents of two different species</a>
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<p>But by looking more closely at the very fabric of the cave, we can learn even more. Dirt – or sediment, to archaeologists – is the material that links all archaeological sites. And it can preserve evidence that would otherwise have little chance of surviving the ravages of time.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/292373/original/file-20190913-35592-2m0u5e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/292373/original/file-20190913-35592-2m0u5e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=719&fit=crop&dpr=1 600w, https://images.theconversation.com/files/292373/original/file-20190913-35592-2m0u5e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=719&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/292373/original/file-20190913-35592-2m0u5e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=719&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/292373/original/file-20190913-35592-2m0u5e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=903&fit=crop&dpr=1 754w, https://images.theconversation.com/files/292373/original/file-20190913-35592-2m0u5e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=903&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/292373/original/file-20190913-35592-2m0u5e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=903&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Block of sediment (dirt) extracted from the site for laboratory analysis.</span>
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</figure>
<p>By using a technique called micromorphology to study archaeological deposits at microscopic scales, we can spot particular features and arrangements of sediment particles that reveal clues about what was happening at the time those sediments were deposited.</p>
<p>This method can potentially identify miniscule traces of detritus left behind by humans living in the cave. These can include the products of burning, such as ash and charcoal, which indicate that humans lit fires there.</p>
<p>Caves are also attractive shelters for other animals, and fossil droppings can indicate the presence of both human and non-human cave dwellers.</p>
<h2>Carnivores’ cave</h2>
<p>The sediment in Denisova Cave contains evidence for its long-term use by humans and other animals, including hyenas, bears and wolves, that inhabited the wider landscape. We indeed found microscopic traces of both human and animal occupation, judging by the dropping fragments we identified.</p>
<p>But curiously, despite the cave having been occupied by humans for hundreds of thousands of years, as evidenced by the many fossils and stone tools already found there, its sediments contain scant evidence for the use of fire.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/292370/original/file-20190913-35624-1brlq9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/292370/original/file-20190913-35624-1brlq9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=225&fit=crop&dpr=1 600w, https://images.theconversation.com/files/292370/original/file-20190913-35624-1brlq9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=225&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/292370/original/file-20190913-35624-1brlq9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=225&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/292370/original/file-20190913-35624-1brlq9y.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=282&fit=crop&dpr=1 754w, https://images.theconversation.com/files/292370/original/file-20190913-35624-1brlq9y.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=282&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/292370/original/file-20190913-35624-1brlq9y.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=282&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Microscope images of fossil hyena dropping (coprolite) with evidence of a meal (bone fragment) contained inside (left), and small charcoal fragments associated with burning by ancient human cave-dwellers (right)</span>
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<p>This is intriguing, as archaeological evidence for fire-use in caves is usually commonplace, even if the sediments have been disturbed by processes such as animal burrowing, erosion by wind or water, or chemical changes to the sediment. </p>
<p>One possibility is that these traces were washed away by percolating water or weathered away by increased acidity.</p>
<p>But what the sediments do clearly tell us is that large carnivores were common visitors to the cave. As humans and large carnivores would not have happily cohabited the cave, this tells us that what we see in the sediments is a compression in time, with animal and human evidence overlain on top of one another.</p>
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Read more:
<a href="https://theconversation.com/southeast-asia-was-crowded-with-archaic-human-groups-long-before-we-turned-up-119818">Southeast Asia was crowded with archaic human groups long before we turned up</a>
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<p>We also recorded the presence of ice in some of the sediments, indicating periods when it was both colder and wetter than at present.</p>
<p>Our findings show just how much we can learn by putting dirt under the microscope. It is likely this “microarchaeological” approach will continue to surprise us with finds that are invisible to the naked eye.</p><img src="https://counter.theconversation.com/content/122458/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mike W Morley receives funding from the Australian Research Council. </span></em></p><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>Paul Goldberg 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>Denisova Cave in Siberia has a rich fossil history of early humans - and deposits of droppings from hyenas, wolves and even bears, according to a new analysis of the cave’s dirt floor.Mike W. Morley, Senior research fellow, Flinders UniversityPaul Goldberg, Associate research scientist, University of WollongongRichard 'Bert' Roberts, Director, ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH), University of WollongongLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1198182019-07-15T05:23:35Z2019-07-15T05:23:35ZSoutheast Asia was crowded with archaic human groups long before we turned up<figure><img src="https://images.theconversation.com/files/283013/original/file-20190708-51273-o0si3h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The ancestral population of modern humans appears to have split as it moved across Asia.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/thursday-island-australia-february-20-2019-1377625862?src=MW-IovWrGzMMMZVGn77kKw-1-15&studio=1">Shutterstock</a></span></figcaption></figure><p>Around 55,000-50,000 years ago, a population of modern humans left Africa and started on the long trek that would lead them around the world. After rapidly crossing Eurasia and Southeast Asia, they travelled through the islands of Indonesia, and eventually as far as <a href="https://theconversation.com/when-did-aboriginal-people-first-arrive-in-australia-100830">the continent of Sahul</a> – modern-day Australia and New Guinea. </p>
<p>Their descendants are the modern human populations found right across this enormous region today.</p>
<p>In new research <a href="https://www.pnas.org/content/early/2019/07/11/1904824116">published in Proceedings of the National Academy of Sciences</a>, we detail how during this remarkable journey the ancestors of modern humans met and genetically mixed with a number of archaic human groups, including Neandertals and Denisovans, and several others for which we currently have no name. The traces of these interactions are still preserved in our genomes. </p>
<p>For example, all modern non-African populations contain about 2% Neandertal ancestry. This strong universal signal shows that the original Neandertal mixing event must have happened just after the small founding population left Africa. </p>
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Read more:
<a href="https://theconversation.com/when-did-aboriginal-people-first-arrive-in-australia-100830">When did Aboriginal people first arrive in Australia?</a>
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<p>We can even use the Neandertal genetic signal to date when they left Africa. The large size of Neandertal DNA fragments in the genome of an ancient skeleton from southern Russia, which is 45,000 years old, shows that at most 230-430 generations could have passed since the initial mixing event (dating it around 50-55,000 years ago).</p>
<p>By analysing where the archaic genetic traces are found today (from previous genetic studies) and using paleovegetation maps that identify favourable savannah-like habitat along the route 55,000 years ago, we have reconstructed the likely geographic locations and number of the archaic hominin mixing events. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/282999/original/file-20190708-51312-1e8uawy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/282999/original/file-20190708-51312-1e8uawy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/282999/original/file-20190708-51312-1e8uawy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=386&fit=crop&dpr=1 600w, https://images.theconversation.com/files/282999/original/file-20190708-51312-1e8uawy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=386&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/282999/original/file-20190708-51312-1e8uawy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=386&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/282999/original/file-20190708-51312-1e8uawy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=485&fit=crop&dpr=1 754w, https://images.theconversation.com/files/282999/original/file-20190708-51312-1e8uawy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=485&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/282999/original/file-20190708-51312-1e8uawy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=485&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">A map showing where the ancestors of modern humans appear to have met and mixed with archaic hominins.</span>
<span class="attribution"><span class="license">Author provided</span></span>
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<h2>Leaving Africa</h2>
<p>One of the first mixing events after the Neandertals appears to have taken place during the movement across southern Asia. The archaic human group involved was neither the Neandertals or Denisovans, but something similar – which currently has no name. </p>
<p>The genetic traces of this archaic group can be found from modern Punjabi and Bengal populations all the way through to New Guinea and Australia. As a result, we think this mixing event (marked 1 on the map) likely took place somewhere around northern India, which is the most “upstream” or westerly position it is first observed.</p>
<p>The ancestral population of modern humans then appears to have split as it moved across Asia with one pulse dispersing north into mainland Asia, where it met and mixed with a Denisovan group (marked 2 on the map). These Denisovans were genetically close to those we already know about from the Altai mountains. The traces of this event can be seen in East Asia today, and also in North and South America populations, who stem from northeastern Asia.</p>
<h2>Island Southeast Asia was already crowded</h2>
<p>The other pulse of modern humans headed south down the Malaysian Peninsula and into Island Southeast Asia (ISEA) where a big surprise awaited. They found the area was already crowded with different archaic human groups, including completely different species. </p>
<p>Recent fossil finds of small skeletons have shown that apparent relatives of <em>Homo erectus</em> (whose early fossils are common on Java) had survived on the Philippines and Flores (where they are known as “hobbits”) until around <a href="https://www.nature.com/articles/d41586-019-01019-7">52,000 years ago</a>. Effectively right up until the modern humans arrived.</p>
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Read more:
<a href="https://theconversation.com/an-incredible-journey-the-first-people-to-arrive-in-australia-came-in-large-numbers-and-on-purpose-114074">An incredible journey: the first people to arrive in Australia came in large numbers, and on purpose</a>
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<p>The incoming modern human population apparently first met and mixed with a distant relative of the Denisovans in the area, leaving a signal in the genomes of Australo-Papuans and several ISEA populations. These signals are very different from the above East Asian mixing event, and instead come from a Denisovan relative that had separated genetically from the Altai/East Asian Denisovans around 280,000 years ago. This mixing event appears to have been somewhere around southern Malaysia/Borneo (marked 3 on the map).</p>
<h2>Landfall in Australia</h2>
<p>The wave of modern humans does not appear to have waited long to cross Wallace’s Line – the famous biogeographic barrier that effectively marks the edge of the ISEA landmasses joined together during past glacial periods, when sea levels were up to 120 metres lower. </p>
<p>We know this because a sudden appearance of archaeological sites right across Australia around 50,000 years ago indicates that modern humans had <a href="https://theconversation.com/an-incredible-journey-the-first-people-to-arrive-in-australia-came-in-large-numbers-and-on-purpose-114074">quickly crossed the marine gaps</a> through ISEA. </p>
<p>While there is one much earlier Australian site, the 65-80,000 year old Madjedbebe rock shelter in Arnhem Land, it is a complete outlier to <a href="https://theconversation.com/australias-epic-story-a-tale-of-amazing-people-amazing-creatures-and-rising-seas-115701">the rest of the Australian record</a> and the age of the site has <a href="https://theconversation.com/when-did-aboriginal-people-first-arrive-in-australia-100830">been queried</a>.</p>
<p>While moving through ISEA, the modern human population appears to have met – and mixed with – two more archaic human groups. Hunter-gatherer populations in the Philippines preserve signals of yet another Denisovan-mixing event (marked 4 on the map), after they had diverged from the main wave of modern humans moving through ISEA. </p>
<p>Similarly, a genetic study of the short-statured modern day population that lives around the Flores cave where the tiny skeletons of the “hobbits” were found identified signals of DNA not from <em>Homo erectus</em>, the target of the study, but an enigmatic signal from something else. The source was neither Neandertal nor Denisovan but something of similar age – yet another currently unknown archaic group (marked 5 on the map).</p>
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<em>
<strong>
Read more:
<a href="https://theconversation.com/australias-epic-story-a-tale-of-amazing-people-amazing-creatures-and-rising-seas-115701">Australia’s epic story: a tale of amazing people, amazing creatures and rising seas</a>
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<h2>The last survivors</h2>
<p>What the different genetic studies across this region tell us is that the ancestors of modern humans appear to have met and mixed with four different archaic hominins, in at least six events. And this all happened in the very short window of time between leaving Africa 50-55,000 years ago, and arriving in Australia and New Guinea at most 5,000 years later. </p>
<p>Remarkably, none of these genetic mixing events appears to have involved fossil species in ISEA that we know were still around when modern humans arrived, such as <em>Homo luzonensis</em> (Philippines) and the Flores hobbits. </p>
<p>ISEA was clearly a very crowded place around 50,000 years ago, occupied by many different archaic human groups on many different islands. But shortly thereafter there was only one survivor: us.</p><img src="https://counter.theconversation.com/content/119818/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>João Teixeira receives funding from the Australian Research Council.</span></em></p>New research outlines how the ancestors of modern humans interbred with several archaic human groups on the passage from Africa to Australia.João Teixeira, Research associate, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1105042019-01-30T19:08:48Z2019-01-30T19:08:48ZFresh clues to the life and times of the Denisovans, a little-known ancient group of humans<figure><img src="https://images.theconversation.com/files/256038/original/file-20190129-108342-1xsrrfp.JPG?ixlib=rb-1.1.0&rect=0%2C966%2C5590%2C2211&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Richard ‘Bert’ Roberts, Vladimir Uliyanov and Maxim Kozlikin (clockwise from top) examining sediments in the East Chamber of Denisova Cave.</span> <span class="attribution"><span class="source">Institute of Archaeology and Ethnography of the Siberian Branch of the Russian Academy of Sciences, Author provided</span></span></figcaption></figure><p>We know that some modern human genomes contain fragments of DNA from an ancient population of humans called Denisovans, the remains of which have been found at only one site, a cave in what is now Siberia.</p>
<p><a href="https://www.nature.com/articles/s41586-018-0843-2">Two</a> <a href="https://www.nature.com/articles/s41586-018-0870-z">papers</a> published in Nature today give us a firmer understanding of when these little-known archaic humans (hominins) lived.</p>
<p>Denisovans were unknown until 2010, when their genome was first <a href="https://www.nature.com/articles/nature08976">announced</a>. The DNA was obtained from a girl’s fingerbone found buried in <a href="https://www.britannica.com/place/Denisova-Cave">Denisova Cave</a> in the Altai Mountains of southern Siberia.</p>
<p>The new studies provide the first robust timeline for the Denisovan fossils and DNA recovered from the cave sediments, as well as the environments that the Denisovans experienced.</p>
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<strong>
Read more:
<a href="https://theconversation.com/borneo-cave-discovery-is-the-worlds-oldest-rock-art-in-southeast-asia-106252">Borneo cave discovery: is the world's oldest rock art in Southeast Asia?</a>
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<p>A few Neanderthal fossils have also been retrieved from the site, along with their genetic traces in the sediments at Denisova Cave, which was first excavated 40 years ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/255683/original/file-20190127-108364-acf5nx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/255683/original/file-20190127-108364-acf5nx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255683/original/file-20190127-108364-acf5nx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=538&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255683/original/file-20190127-108364-acf5nx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=538&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255683/original/file-20190127-108364-acf5nx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=538&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255683/original/file-20190127-108364-acf5nx.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=676&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255683/original/file-20190127-108364-acf5nx.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=676&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255683/original/file-20190127-108364-acf5nx.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=676&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Location map of Denisova Cave and photo (inset) of cave entrance.</span>
<span class="attribution"><span class="source">Institute of Archaeology and Ethnography of the Siberian Branch of the Russian Academy of Sciences/Bert Roberts</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Modern humans (<em>Homo sapiens</em>) arrived later, making the site unique in the world as home to three groups of humans at various times.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/255689/original/file-20190127-108364-1bxphf2.gif?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/255689/original/file-20190127-108364-1bxphf2.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255689/original/file-20190127-108364-1bxphf2.gif?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=417&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255689/original/file-20190127-108364-1bxphf2.gif?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=417&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255689/original/file-20190127-108364-1bxphf2.gif?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=417&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255689/original/file-20190127-108364-1bxphf2.gif?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=524&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255689/original/file-20190127-108364-1bxphf2.gif?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=524&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255689/original/file-20190127-108364-1bxphf2.gif?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=524&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">All fossils of Denisovans and Neanderthals, and hominin bones not assigned to either group, discovered at Denisova Cave. Next to each fossil is the specimen number (for example, Denisova 2 in the top-left corner).</span>
<span class="attribution"><span class="source">Zenobia Jacobs</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Who were the Denisovans?</h2>
<p>We currently know much more about the DNA of Denisovans than we do about their physical appearance, as hominin fossils are exceedingly rare at the site. </p>
<p>Besides the fingerbone, a total of three teeth have been genetically identified as Denisovan. The DNA from a tiny fragment of long bone from the <a href="https://www.nature.com/articles/d41586-018-06004-0">daughter of Denisovan and Neanderthal parents</a> provides direct evidence that the two groups met and interbred at least once.</p>
<p>We know frustratingly little about the geographic distribution and demography of the Denisovans, except for the head-scratching finding that Aboriginal Australians and New Guineans are the only people alive today with substantial amounts of <a href="https://www.newscientist.com/article/mg21128323-200-the-vast-asian-realm-of-the-lost-humans/">Denisovan DNA in their genome</a>.</p>
<p>But while hominin fossils are few and far between at Denisova Cave, the deposits contain thousands of artefacts made from stone. The upper layers also contain artefacts crafted from other materials, including ornaments made of marble, bone, animal teeth, mammoth ivory and ostrich eggshell. There are also animal and plant remains that bear witness to past environmental conditions.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/255685/original/file-20190127-108351-9r1sf2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/255685/original/file-20190127-108351-9r1sf2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255685/original/file-20190127-108351-9r1sf2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=799&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255685/original/file-20190127-108351-9r1sf2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=799&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255685/original/file-20190127-108351-9r1sf2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=799&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255685/original/file-20190127-108351-9r1sf2.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1004&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255685/original/file-20190127-108351-9r1sf2.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1004&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255685/original/file-20190127-108351-9r1sf2.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1004&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Selection of artefacts from Denisova Cave. a, Upper Palaeolithic; b, Initial Upper Palaeolithic; c, middle Middle Palaeolithic; and d, early Middle Palaeolithic.</span>
<span class="attribution"><span class="source">Institute of Archaeology and Ethnography of the Siberian Branch of the Russian Academy of Sciences</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<h2>Dating the Denisovans</h2>
<p>Despite the importance of Denisova Cave to studies of human evolution, the history of the site and its inhabitants has persisted as a puzzle, due to the lack of a reliable timescale for the cave deposits and their contents.</p>
<p>With the publication of the two new papers, some of the critical pieces of this puzzle now fall into place.</p>
<p>The new studies build on the detailed work carried out by our Russian colleagues over several decades in all three chambers of Denisova Cave. They have painstakingly documented the complex layering of the deposits, along with the excavated cultural, animal and plant remains.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/255686/original/file-20190127-108364-f8a665.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/255686/original/file-20190127-108364-f8a665.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255686/original/file-20190127-108364-f8a665.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255686/original/file-20190127-108364-f8a665.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255686/original/file-20190127-108364-f8a665.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255686/original/file-20190127-108364-f8a665.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255686/original/file-20190127-108364-f8a665.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255686/original/file-20190127-108364-f8a665.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">Sediment profiles (stratigraphy) in Denisova Cave: a, Main Chamber; b, East Chamber. The string lines in each photo are 50 cm apart.</span>
<span class="attribution"><span class="source">Institute of Archaeology and Ethnography of the Siberian Branch of the Russian Academy of Sciences</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We used <a href="https://www.aber.ac.uk/en/media/departmental/dges/pdf/english_heritage_luminescence_dating.pdf">optical dating</a> to determine when the sediments were last exposed to sunlight and deposited in the cave. Optical dating has been applied to archaeological sites around the world, with the minerals quartz and potassium feldspar most often used.</p>
<p>We measured more than 280,000 individual grains of these minerals from more than 100 samples using a combination of well-established and new procedures.</p>
<p>This enabled us to carry out a variety of experimental cross-checks, identify parts of the deposit that had been disturbed, date the oldest sediment layers, and construct a <a href="https://www.nature.com/articles/s41586-018-0843-2">robust chronology for the site</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/255687/original/file-20190127-108367-1ofso8e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/255687/original/file-20190127-108367-1ofso8e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255687/original/file-20190127-108367-1ofso8e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255687/original/file-20190127-108367-1ofso8e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255687/original/file-20190127-108367-1ofso8e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255687/original/file-20190127-108367-1ofso8e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255687/original/file-20190127-108367-1ofso8e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255687/original/file-20190127-108367-1ofso8e.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">Optical dating of sediments: a, Zenobia Jacobs in the red-lit laboratory at the University of Wollongong; b, Sample holder for 100 individual sand-sized grains; b, Sample holders loaded onto carousel for optical dating of individual grains; d, green laser beam used to stimulate quartz grains in optical dating.</span>
<span class="attribution"><span class="source">University of Wollongong/Erich Fisher</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>To better constrain the ages of the hominin fossils, our colleagues at the University of Oxford, UK, and two of the Max Planck Institutes in Germany developed a <a href="https://www.nature.com/articles/s41586-018-0870-z">new statistical (Bayesian) model</a>.</p>
<p>The new studies show that hominins have occupied the site almost continuously through relatively warm and cold periods over the past 300,000 years, leaving behind stone tools and other artefacts in the cave deposits.</p>
<p>Fossils and DNA traces of Denisovans are found from at least 200,000 to 50,000 years ago, and those of Neanderthals from between 200,000 and 100,000 years ago. The girl with mixed ancestry reveals that the two groups of hominins met and interbred around 100,000 years ago.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/255682/original/file-20190127-108338-fbjbxe.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/255682/original/file-20190127-108338-fbjbxe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/255682/original/file-20190127-108338-fbjbxe.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=296&fit=crop&dpr=1 600w, https://images.theconversation.com/files/255682/original/file-20190127-108338-fbjbxe.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=296&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/255682/original/file-20190127-108338-fbjbxe.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=296&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/255682/original/file-20190127-108338-fbjbxe.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=372&fit=crop&dpr=1 754w, https://images.theconversation.com/files/255682/original/file-20190127-108338-fbjbxe.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=372&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/255682/original/file-20190127-108338-fbjbxe.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=372&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Summary timeline for the archaeology, hominin fossils and hominin DNA retrieved from the sediments at Denisova Cave. All age ranges are shown at the 95.4% confidence interval.</span>
<span class="attribution"><span class="source">Bert Roberts</span>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Although Denisovans persisted at the site until 50,000 years ago, this does not preclude their later survival elsewhere. They were evidently a hardy bunch, living through multiple episodes of the cold Siberian climate before finally going extinct.</p>
<h2>An incomplete history</h2>
<p>We now know much more about the life and times of the Denisovans, but there are still many unanswered questions.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/ancient-teenager-the-first-known-person-with-parents-of-two-different-species-101965">Ancient teenager the first known person with parents of two different species</a>
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<p>For example, we don’t know the nature of any encounters between them and modern humans, who were already present in <a href="http://theconversation.com/old-teeth-from-a-rediscovered-cave-show-humans-were-in-indonesia-more-than-63-000-years-ago-82075">other parts of Asia</a> and in <a href="https://theconversation.com/buried-tools-and-pigments-tell-a-new-history-of-humans-in-australia-for-65-000-years-81021">Australia</a> by 50,000 years ago.</p>
<p>So while our understanding of the history of Denisovans has come a long way since 2010, there are still many missing pieces of this intriguing puzzle.</p><img src="https://counter.theconversation.com/content/110504/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Zenobia Jacobs receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Bo Li receives funding from the Australian Research Council. </span></em></p><p class="fine-print"><em><span>Kieran O'Gorman receives funding from the Australian Government Research Training Program. </span></em></p><p class="fine-print"><em><span>Richard 'Bert' Roberts receives funding from the Australian Research Council.</span></em></p>New studies reveal when the Denisovans and their Neanderthal cousins occupied a cave in southern Siberia. It’s the only site known to have been inhabited by them and by modern humans.Zenobia Jacobs, Professor, University of WollongongBo Li, Principal Research Fellow in Archaeological Science, University of WollongongKieran O'Gorman, PhD candidate, University of WollongongRichard 'Bert' Roberts, Director, ARC Centre of Excellence for Australian Biodiversity and Heritage (CABAH), University of WollongongLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1019652018-08-22T20:04:32Z2018-08-22T20:04:32ZAncient teenager the first known person with parents of two different species<figure><img src="https://images.theconversation.com/files/232983/original/file-20180822-149484-1jq00oc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">We don't have the full skeleton of a Denisovan so we don't really know what they looked like. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/cave-people-by-fire-neanderthals-original-789130387?src=zsk4PRNGIg4gsAutupFX8A-1-0">from www.shutterstock.com </a></span></figcaption></figure><p>A new <a href="http://discovermagazine.com/2017/jul-aug/ancient-dna">ancient DNA</a> study <a href="https://www.nature.com/articles/s41586-018-0455-x">published in Nature today</a> reports the first known person to have had parents of two different species. The studied remains belonged to a girl who had a Neanderthal mother and a Denisovan father. </p>
<p><a href="http://humanorigins.si.edu/evidence/human-fossils/species/homo-neanderthalensis">Neanderthals</a> (<em>Homo neanderthalensis</em>) lived throughout Europe and Western Asia until around 30,000 years ago. This species lived in several different ecological zones, survived three glacial periods, and were excellent hunters and tool-makers. </p>
<p><a href="https://www.history.com/topics/denisovans">Denisovans</a> (<em>Homo sapiens denisova</em>), on the other hand, we know very little about. Thus far they have only been found in Denisova Cave in Sibera as tiny bone fragments. We don’t yet know what they looked like – nor exactly what they were capable of. </p>
<p>Neanderthal, Denisovans, and modern humans all shared a common ancestor more than 400,000 years ago. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/232980/original/file-20180822-149496-wrlmga.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/232980/original/file-20180822-149496-wrlmga.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/232980/original/file-20180822-149496-wrlmga.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/232980/original/file-20180822-149496-wrlmga.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/232980/original/file-20180822-149496-wrlmga.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/232980/original/file-20180822-149496-wrlmga.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/232980/original/file-20180822-149496-wrlmga.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">Is this what Denisova 11’s mother looked like? A museum model of a Neanderthal woman.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/madrid-spain-july-10-2016-lifesized-455061862?src=ia6LoWjeYu9LTg1n5e5_Wg-1-8">from www.shutterstock.com</a></span>
</figcaption>
</figure>
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<p>
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<strong>
Read more:
<a href="https://theconversation.com/why-the-neanderthals-may-have-been-more-sophisticated-hunters-than-we-thought-new-study-98870">Why the Neanderthals may have been more sophisticated hunters than we thought – new study</a>
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<p>Found in <a href="http://www.sciencemag.org/news/2015/09/siberian-cave-was-home-generations-mysterious-ancient-humans">Denisova Cave</a>, this child — known as “Denisova 11” — was at least 13 years of age at the time of her death. Analysis of a piece of her bone found that the girl died around 90,000 years ago. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/232989/original/file-20180822-149493-6v5dwo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/232989/original/file-20180822-149493-6v5dwo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=516&fit=crop&dpr=1 600w, https://images.theconversation.com/files/232989/original/file-20180822-149493-6v5dwo.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=516&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/232989/original/file-20180822-149493-6v5dwo.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=516&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/232989/original/file-20180822-149493-6v5dwo.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=649&fit=crop&dpr=1 754w, https://images.theconversation.com/files/232989/original/file-20180822-149493-6v5dwo.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=649&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/232989/original/file-20180822-149493-6v5dwo.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=649&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Over many thousands of years, Denisova Cave in Siberia was occupied by Denisovans, Neanderthals and modern humans.</span>
<span class="attribution"><span class="source">Google Earth</span></span>
</figcaption>
</figure>
<p>This discovery occurred through <a href="http://discovermagazine.com/2017/jul-aug/ancient-dna">ancient DNA analysis</a>, whereby a small piece of the teenager’s bone was pulverised, the DNA extracted, and then sequenced. The sequence was then compared to previously analysed samples from Neanderthals, modern humans, and Denisovans. Her genetic traits could only be explained if her mother was a Neanderthal and her father was a Denisovan. </p>
<p>Denisova 11 was a first generation Neanderthal-Denisovan woman – perhaps we could call her a “Neandersovan”?</p>
<h2>Neighbours of modern humans</h2>
<p><a href="http://humanorigins.si.edu/evidence/human-fossils/species/homo-neanderthalensis">Neanderthals</a> and <a href="https://www.history.com/topics/denisovans">Denisovans</a> inhabited Eurasia until about 40,000 years ago when they were <a href="https://www.inverse.com/article/38035-neanderthal-demise-modern-human-replacement">replaced by modern humans</a> (<em>Homo sapiens</em>). </p>
<p>But before this replacement occurred, there appears to have been a fair bit of mingling going on whenever the different groups met. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/232975/original/file-20180822-149493-1bnw2ll.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/232975/original/file-20180822-149493-1bnw2ll.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=800&fit=crop&dpr=1 600w, https://images.theconversation.com/files/232975/original/file-20180822-149493-1bnw2ll.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=800&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/232975/original/file-20180822-149493-1bnw2ll.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=800&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/232975/original/file-20180822-149493-1bnw2ll.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1005&fit=crop&dpr=1 754w, https://images.theconversation.com/files/232975/original/file-20180822-149493-1bnw2ll.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1005&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/232975/original/file-20180822-149493-1bnw2ll.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">
<figcaption>
<span class="caption">Where ancient people roamed: the valley above the Denisova Cave archaeological site, Russia.</span>
<span class="attribution"><a class="source" href="https://www.smc.org.au/">Bence Viola</a></span>
</figcaption>
</figure>
<p>Indeed, the ancestors of <a href="https://genographic.nationalgeographic.com/denisovan/">modern-day Oceanians and Asians</a> contain Denisovan DNA, while present-day non-Africans contain <a href="https://genographic.nationalgeographic.com/neanderthal/">2-4% Neanderthal DNA</a>. </p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/neanderthals-didnt-give-us-red-hair-but-they-certainly-changed-the-way-we-sleep-85173">Neanderthals didn't give us red hair but they certainly changed the way we sleep</a>
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<h2>More mobile than we thought</h2>
<p>The DNA of this girl — Denisova 11 — also suggests that there was some quite significant movement of Neanderthal groups between Western Europe and the East. Analysis of her DNA found that rather than being more closely related to a Neanderthal who lived in her home cave sometime prior to her birth, she instead showed more connections to those recovered in Western Europe.</p>
<p>This finding is interesting because most <a href="https://www.sciencedirect.com/science/article/pii/S1040618216001968">archaeological evidence</a> indicates that Neanderthals — unlike modern humans — were not interested in long-distance movement. They don’t seem to have moved much beyond relatively <a href="https://www.newscientist.com/article/mg21328470-400-into-the-mind-of-a-neanderthal/">constrained territories</a> which provided everything they needed for day-to-day life.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/neanderthals-cared-for-each-other-and-survived-into-old-age-new-research-93110">Neanderthals cared for each other and survived into old age – new research</a>
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</em>
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<p>Denisova 11 suggests that at least some major movement of ancient humans occurred between west and east. But when? And why? </p>
<p>And how did a Neanderthal woman meet a Denisovan man? How did their respective communities interact? These are questions that now must be asked and investigated.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/232978/original/file-20180822-149478-3ykf5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/232978/original/file-20180822-149478-3ykf5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/232978/original/file-20180822-149478-3ykf5o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/232978/original/file-20180822-149478-3ykf5o.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/232978/original/file-20180822-149478-3ykf5o.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/232978/original/file-20180822-149478-3ykf5o.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/232978/original/file-20180822-149478-3ykf5o.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">Scientists found the unique bone in the East Chamber of Denisova Cave, Russia.</span>
<span class="attribution"><a class="source" href="https://www.smc.org.au/">Bence Viola</a></span>
</figcaption>
</figure>
<h2>Mystery girl</h2>
<p>While this young girl has told us so much about her ancestors, we know very little about her. </p>
<p>Because it was only a small piece of one of her long bones found, we don’t know how she died. We can’t know if she suffered any serious illness in her short life, nor if she ever broke a bone. </p>
<p>We only know that she lived.</p><img src="https://counter.theconversation.com/content/101965/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michelle Langley is an Australian Research Council DECRA Research Fellow in the Australian Research Centre for Human Evolution at Griffith University.</span></em></p>Ancient DNA in a 50,000+ year old bone tells us that two species of early humans did produce offspring together.Michelle Langley, ARC DECRA Research Fellow, Griffith UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/657452016-09-21T17:07:13Z2016-09-21T17:07:13ZGenetic studies reveal diversity of early human populations – and pin down when we left Africa<figure><img src="https://images.theconversation.com/files/138606/original/image-20160921-21711-9j6rw8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Aubrey Lynch, elder from the Wongatha Aboriginal language group, participated in one of the studies. </span> <span class="attribution"><span class="source">Preben Hjort, Mayday Film.</span></span></figcaption></figure><p>Humans are a success story like no other. We are now living in the “Anthropocene” age, meaning much of what we see around us has been made or influenced by people. Amazingly, all humans alive today – from the inhabitants of Tierra del Fuego on the southern tip of the Americas to the Sherpa in the Himalayas and the mountain tribes of Papua New Guinea – came from one common ancestor. </p>
<p>We know that our lineage arose in Africa and quickly spread to the four corners of the globe. But the details are murky. Was there just one population of early humans in Africa at the time? When exactly did we first leave the continent and was there just one exodus? Some scientists believe that all non-Africans today can trace their ancestry back to a single migrant population, while others argue that there were several different waves of migration out of Africa.</p>
<p>Now, three new studies mapping the genetic profiles of more than 200 populations across the world, published in <em>Nature</em>, have started to answer some of these questions. </p>
<h2>Out of Africa</h2>
<p>Humans initially spread out of Africa through the Middle East, ranging further north into Europe, east across Asia and south to Australasia. Later, they eventually spread north-east <a href="https://theconversation.com/first-americans-lived-on-land-bridge-for-thousands-of-years-genetics-study-suggests-23747">over the top of Beringia</a> into the Americas. We are now almost certain that on their way across the globe, <a href="http://www.nature.com/nature/journal/v524/n7564/full/nature14558.html">our ancestors interbred with</a> at least two archaic human species, the Neanderthals in Eurasia, and the <a href="http://www.nature.com/nature/journal/v468/n7327/abs/nature09710.html">Denisovans</a> in Asia. </p>
<p>Genetics has been invaluable in understanding this past. While <a href="http://science.sciencemag.org/content/239/4845/1263">hominin fossils hinted</a> that Africa was the birthplace of humanity, it was genetics that <a href="http://www.nature.com/nature/journal/v325/n6099/abs/325031a0.html">proved this to be so</a>. Patterns of genetic variation – how similar or different people’s DNA sequences are – have not only shown that most of the diversity we see in humans today is present within Africa, but also that there are fewer differences within populations the further you get from Africa. </p>
<p>These observations support the “Out of Africa” model; the idea that a small number of Africans moved out of the continent – taking a much reduced gene-pool with them. This genetic bottleneck, and the subsequent growth of non-African populations, meant that there was less genetic diversity to go round, and so there are fewer differences, on average, between the genomes of non-Africans compared to Africans.</p>
<p>When we scan two genomes to identify where these differences, or mutations, lie, we can estimate how long in the past those genomes split from each other. If two genomes share long stretches with no differences, it’s likely that their common ancestor was in the more recent past than the ancestor of two genomes with shorter shared stretches. By interrogating the distribution of mutations between African and non-African genomes, two of the papers just about agree that the genetic bottleneck caused by the migration out of Africa occurred roughly 60,000 years ago. This is also broadly in line with dating from archaeological investigations.</p>
<p>Their research also manages to settle a long-running debate about the structure of African populations at the beginning of the migration. Was the small group of humans who left Africa representative of the whole continent at that time, or had they split off from more southerly populations earlier?</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=464&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=464&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=464&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=583&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=583&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138486/original/image-20160920-12453-wwkp61.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=583&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">SGDP model of the relationships among diverse humans (select ancient samples are shown in red) that fits the data.</span>
<span class="attribution"><span class="source">Credit: Swapan Mallick, Mark Lipson and David Reich.</span></span>
</figcaption>
</figure>
<p>The Simons Genome Diversity Project compared the genomes of 142 worldwide populations, including 20 from across Africa. They <a href="http://nature.com/articles/doi:10.1038/nature18299">conclusively show</a> that modern African hunter-gatherer populations split off from the group that became non-Africans around 130,000 years ago and from West Africans around 90,000 years ago. This indicates that there was substantial substructure of populations in Africa prior to the wave of migration. A second study, led by Danish geneticist Eske Willersev, with far fewer African samples, used similar methods <a href="http://nature.com/articles/doi:10.1038/nature18964">to show</a> that divergence within Africa also started before the migration, around 125,000 years ago.</p>
<h2>More migrations?</h2>
<p>Following the move out of the continent, the pioneers must then have journeyed incredibly quickly to Australia. The Danish study, the most comprehensive analysis of Aboriginal Australian and Papuan genomes to date, is the first to really examine the position of Australia at the end of the migration.</p>
<p>They found that the ancestors of populations from “Sahul” – Tasmania, Australia and New Guinea – split from the common ancestor of Europeans and Asians 51,000-72,000 years ago. This is prior to their split from each other around 29,000-55,000 years ago, and almost immediately after the move out of Africa. This implies that the group of people who ended up in the Sahul split away from others almost as soon as the initial group left Africa. Substantial mixing with Denisovans is only seen in Sahulians, which is consistent with this early split.</p>
<p>Crucially, because the ancestors of modern-day Europeans and Asians hadn’t split in two at this point, we think that they must have still been somewhere in western Eurasia at this point. This means that there must have been a second migration from west Eurasia into east Asia later on. The Simons Genome Diversity Project study, by contrast, albeit with a far smaller sample of Sahulian genomes, found no evidence for such an early Sahulian split. It instead shows that the ancestors of East Asians and Sahulians split from western Eurasians before they split from each other, and therefore that Denisovan admixture occurred after the former split from each other.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=553&fit=crop&dpr=1 600w, https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=553&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=553&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=694&fit=crop&dpr=1 754w, https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=694&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/138484/original/image-20160920-12465-1c3mlo8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=694&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A graphic representation of the interaction between modern and archaic human lines, showing traces of an early out of Africa (xOoA) expansion within the genome of modern Sahul populations.</span>
<span class="attribution"><span class="source">Dr Mait Metspalu at the Estonian Biocentre, Tartu, Estonia</span></span>
</figcaption>
</figure>
<p>Meanwhile, a third paper <a href="http://nature.com/articles/doi:10.1038/nature19792">proposes an earlier, “extra” migration</a> out of Africa, some 120,000 years ago. This migration is only visible in the genomes of a separate set of Sahulians sequenced as part of the Estonian Biocentre Human Genome Diversity Panel. Only around 2% per cent of these genomes can be traced to this earlier migration event, which implies that this wave can’t have many ancestors left in the present day. If true (the two other papers find little support for it), this suggests that there must have been a migration across Asia prior to the big one about 60,000 years ago, and that anatomically modern human populations left Africa earlier than many think.</p>
<p>Whatever the reality of the detail of the Out of Africa event, these studies provide some benchmarks for the timings of some of the key events. Importantly, they are also a huge resource of over 600 new and diverse human genomes that provide the genomics community with the opportunity for further understanding of the paths our ancestors took towards the Anthropocene.</p><img src="https://counter.theconversation.com/content/65745/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>George Busby 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>New research into how early humans spread across the world settles several long-running debates.George Busby, Research Associate in Statistical Genomics, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/288182014-07-04T14:14:48Z2014-07-04T14:14:48ZHow breeding with an ancient human species gave Tibetans their head for heights<figure><img src="https://images.theconversation.com/files/53050/original/vdnxkndh-1404469861.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Cool in the clouds.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/darcym/47498371/">darcym</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>A new study of the DNA of Tibetans has looked at the gene underlying their ability to live in the low-oxygen conditions at high altitudes. It found that this gene has come from an unexpected source – the mysterious group of ancient humans called the Denisovans. This work, a collaboration between Chinese, Danish and American scientists, has been published in the journal <a href="http://dx.doi.org/10.1038/nature13408">Nature</a>.</p>
<p>In the 1990s, a consensus existed about the origin of our human species, <em>Homo sapiens</em>. Our species is young, evolving in Africa around 200,000 years ago, and spreading throughout the world, reaching Europe perhaps only 60,000 years ago. </p>
<p>But we are not the first species of the genus Homo to live in Europe. Fossils from 300,000 to 30,000 years ago reveal the Neanderthal people, <em>Homo neanderthalensis</em>. Many viewed the process where modern Europeans and Asians left Africa and supplanted the Neanderthals as a complete replacement, with no interbreeding. This is what the fossils seemed to say, and seemed confirmed when the sequence of one small part of the Neanderthals’ DNA – that found in the cell’s mitochondria, revealed the Neanderthals to be quite distinct from all modern humans.</p>
<h2>More than just us</h2>
<p>But, in 2010, studies refuted this simple picture. The <a href="http://www.eva.mpg.de/neandertal/index.html">Neanderthal genome project</a> found that Modern Europeans and Asians, but not Africans, had somewhere between 1% and 4% of their DNA that came from the Neanderthals. There had been interbreeding between the groups after all.</p>
<p>But another surprise was looming. In a cave at Denisova in Siberia, fragmentary human sub-fossils, around 50,000 years old, yielded high-quality DNA, and from them the genome of the “Denisovans” was <a href="http://www.eva.mpg.de/denisova">sequenced</a>. And the Denisovans were almost as genetically different from Neanderthals as are modern humans. Suddenly, we had to get used to three distinct groups of humans 50,000 years ago. Did the Denisovans breed with modern humans? Apparently, yes, as a small proportion of modern New Guineans’ DNA showed strong similarity to Denisovan sequences.</p>
<p>While this ancient DNA was surprising to the scientific world, researchers were looking at modern human DNA to find evidence for recent adaptations arising by natural selection. For some studies the goal was to identify the genetic causes of the important biological differences between modern humans and our ancestors, as in the search for “genes for language” or such. Other researchers identified local adaptations in specific human populations, which had evolved to allow them to cope with unusual local environments.</p>
<p>It was the latter that went looking for genetic variants that may have led to adaptation among Tibetans that allowed them to live 4,000 metres above sea level, where the oxygen concentration is less than half of that at sea level. They found that one gene, called <em>EPAS1</em>, makes a protein that regulates many genes involved in how the body processes oxygen. The variant of the gene seen in Tibetans is also seen in related high-mountain people like the Sherpas and Mongolians.</p>
<p><em>EPAS1</em> showed a “signature of selection” in the Tibetans, where an initially rare variant had become common in the population though natural selection. But the assumption was, as in other cases of local adaptation in humans, that the low-oxygen-adapted version of this gene was created by a random mutation in the modern humans (<em>Homo sapiens</em>) of Central Asia.</p>
<h2>Interbreeding can help</h2>
<p>The new study has revealed an unexpected result. By sequencing this gene in many Tibetans, and Han Chinese for comparison, the authors initially showed that this gene is indeed unusually different between Tibetans and the Chinese compared to the rest of their chromosomes. This confirms that natural selection played a role in the difference observed. </p>
<p>But the gene showed too many differences from the Han Chinese. That is why an explanation beyond natural selection was needed. Nothing like it was seen in any other modern human populations, but something like it did exist in the databases- the Denisovans’ version of the same gene. </p>
<p>So, it seemed that, in this case of local adaptation is the result of acquiring a gene from a pre-existing human group – the Denisovans. Among them, it had presumably been carrying out the role of low-oxygen adaptation for hundreds of thousands of years. This gene then spread in the one modern human group whose environment necessitated it.</p>
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<p><em>Next, read this: <a href="https://theconversation.com/out-of-africa-modern-humans-left-the-home-continent-in-at-least-two-waves-25834">Out of Africa: modern humans left the home continent in at least two waves</a></em></p><img src="https://counter.theconversation.com/content/28818/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>John Brookfield 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>A new study of the DNA of Tibetans has looked at the gene underlying their ability to live in the low-oxygen conditions at high altitudes. It found that this gene has come from an unexpected source – the…John Brookfield, Professor of Evolutionary Genetics, University of NottinghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/34652011-09-22T20:47:17Z2011-09-22T20:47:17ZSex with our evolutionary cousins? What’s not to love?<figure><img src="https://images.theconversation.com/files/3798/original/Kaptain_Kobold.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">So what's it to be, buddy, my cave or yours?</span> <span class="attribution"><span class="source">Kaptain Kobold</span></span></figcaption></figure><p>We humans had sex with Neandertals; we bonked the relatives of Neandertals; we got down and dirty with members of an as-yet unrecognised African population; and we, of course, got jiggy with each other. </p>
<p>Yes, we really got around, as shown by papers such as the one published today in the <a href="http://www.cell.com/AJHG/">American Journal of Human Genetics</a>. </p>
<p>It’s a remarkable story, within an even more remarkable framework.</p>
<p>That’s because the 150-year-old study of human evolution is in the midst of a revolution. It’s a transformation with implications as immense as the “discovery” by Darwin of <a href="http://theconversation.com/explainer-theory-of-evolution-2276">Natural Selection</a>. </p>
<p>Yet it’s a revolution just beginning, and one that has barely touched the thinking of most anthropologists who, like me, are specialists in the fossilised remains of our ancestors.</p>
<p>Geneticists now have the capacity to extract and compare the DNA of our long-extinct cousins with our own genes, and to understand not just our biological relationships to them, but also differences in function between our genes, and their impact on our genome through hybridisation. </p>
<p>As already said, this shows our ancestors were “shagging” the Neandertals, with each of us carrying around the genetic legacy of a rather unique love affair! </p>
<p>The closest image in my mind is a fling between <a href="http://1.bp.blogspot.com/-8-YMeBqI9_Q/TcIacrhWaMI/AAAAAAAACqA/TcPtkA638mg/s1600/Captain+Kirk+Buried+in+Tribbles.jpg">Captain Kirk</a> and a <a href="http://starbase400.org/pegasus/bios/Mektor.jpg">female Klingon</a>.</p>
<p>We humans are the product of hybrid mating between early modern humans (who looked just like people alive today around the globe) and archaic humans, including the Neandertals. </p>
<p>And also the “<a href="http://www.time.com/time/health/article/0,8599,1974903,00.html/">Denisovans</a>”, a 30-50 thousand year old relative of Neandertals found in a cave in Central Asia – known from a single tooth and a finger bone.</p>
<p>We were also doing the love-thang with an archaic African population, as yet unrecognised from the fossil record, although its DNA signature is clear among living Africans. </p>
<p>Talk about sowing the seeds of love! Keep your woolly mammoth cloaks on, boys!</p>
<p>The American Journal of Human Genetics paper, by Harvard geneticist David Reich and his international colleagues, has compared the genome of the extinct Denisovans to those of a wide range of living Asians and Oceanians. </p>
<p>Over the last 30 years, a large body of DNA evidence has accumulated supporting the peopling of Asia in a single dispersal of modern humans from Africa 60,000 to 70,000 years ago. </p>
<p>It was, after hundreds of confirmatory studies, cut and dry. </p>
<p>Modern humans got into the region (actually right across Eurasia) either after archaic humans had long gone extinct, or were pushed to extinction by invading moderns. </p>
<p>This was the earliest example of megafaunal extinction, and one with a rather unsavory twist.</p>
<p>But until last year, when the fossilised <a href="http://www.eva.mpg.de/neandertal/press/presskit-neandertal/pdf/Science_Green.pdf">Neandertal genome</a> was published by US anthropologist Richard Green and colleagues, there was no evidence in human DNA for any hanky panky. </p>
<p>We were genetically untarnished by our archaic cousins. A number of possible hybrid skeletons were hotly debated, but largely disbelieved by anthropologists. </p>
<p>The Neandertal genome from 2010 showed that 1-4% of the DNA of living non-Africans had its origins through interbreeding with this archaic population.</p>
<p>In December 2010, the same geneticists published the <a href="http://genome.ucsc.edu/cgi-bin/hgTrackUi?db=hg18&c=chrX&g=bamSLDenisova">genome of the Denisovans</a> and argued that there was evidence for up to 6% of the DNA of living Papua New Guineans having originated from interbreeding. </p>
<p>Yet, Papua New Guinea is a hell of a long way from Central Asia (i.e. Siberia). The study raised many more questions than it answered and left some anthropologists deeply troubled.</p>
<p>This new work builds dramatically on the earlier Denisova work. It suggests modern humans colonised East Asia/Oceania in two waves: one from Africa, following a southern route into Southeast Asia, and a much later one, perhaps from the north. </p>
<p>All of these people carried Neandertal DNA.</p>
<p>Moreover, the earliest immigrants into East Asia/Oceania, the ancestors of indigenous people living today in the southern Philippines, eastern Indonesia, Papua New Guinea and Australia, apparently also interbred with the Denisovans in Southeast Asia before settling distant parts of our region. That’s two interbreeding events!</p>
<p>But how can this be? Southeast Asia, the geographic source of most modern humans in our region tens of thousands of years ago, is a long way south and east of Siberia, the location of the cave where the Denisovan bone was found. </p>
<p>The only solution is that the Denisovan population must have had a very broad geographical distribution, one that spanned Siberia to the tropics of Southeast Asia.</p>
<p>Were the Denisovans Neandertals on a tropical holiday? Or a hitherto unknown archaic population from Southeast Asia?</p>
<p>While answering some of the questions I had from the last Denisova installment, this new study raises a whole set of new ones. I guess only more fossils and fossil DNA will provide the answers. </p>
<p>There has never been a more exciting time to be a student of human evolution. I’m sure Darwin would have been astonished.</p><img src="https://counter.theconversation.com/content/3465/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Darren Curnoe receives funding from the Australian Research Council.</span></em></p>We humans had sex with Neandertals; we bonked the relatives of Neandertals; we got down and dirty with members of an as-yet unrecognised African population; and we, of course, got jiggy with each other…Darren Curnoe, Human evolution specialist, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.