tag:theconversation.com,2011:/es/topics/svante-paabo-127928/articlesSvante Pääbo – The Conversation2022-10-07T12:22:44Ztag: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>
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<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>
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<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>
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<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>
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<p>The world has learned a startling amount about <a href="https://theconversation.com/six-recent-discoveries-that-have-changed-how-we-think-about-human-origins-190274">our human origins</a> in the last dozen years since Pääbo and teammates’ groundbreaking discoveries. And the field of paleogenomics has rapidly expanded. Scientists have now sequenced <a href="https://theconversation.com/we-sequenced-the-oldest-ever-dna-from-million-year-old-mammoths-155485">mammoths that lived a million years ago</a>. Ancient DNA has addressed questions ranging from the origins of the <a href="https://www.sapiens.org/archaeology/ancient-dna-native-americans/">first Americans</a> to the domestication of <a href="https://www.smithsonianmag.com/smart-news/genetic-sequencing-pinpoints-the-origins-of-the-domestic-horse-180978926/">horses</a> and <a href="https://bigthink.com/the-past/ancient-dogs/">dogs</a>, the spread of <a href="https://theconversation.com/ancient-dna-is-revealing-the-origins-of-livestock-herding-in-africa-114387">livestock herding</a> and our bodies’ adaptations – or lack thereof – to <a href="https://www.newscientist.com/article/2331213-evolution-of-lactose-tolerance-probably-driven-by-famine-and-disease/">drinking milk</a>. Ancient DNA can even shed light on <a href="https://doi.org/10.1073/pnas.2120786119">social questions</a> of marriage, kinship and mobility. Researchers can now sequence DNA not only from the remains of ancient humans, animals and plants, but even from their <a href="https://theconversation.com/digging-deep-dna-molecules-in-ancient-dirt-offer-a-treasure-trove-of-clues-to-our-past-172489">traces left in cave dirt</a>.</p>
<p>Alongside this growth in research, people have been grappling with <a href="https://theconversation.com/ancient-dna-unearths-fascinating-secrets-but-what-about-the-ethics-85186">concerns about the speed</a> with which skeletal collections around the world have been sampled for aDNA, leading to broader conversations about <a href="https://theconversation.com/rights-of-the-dead-and-the-living-clash-when-scientists-extract-dna-from-human-remains-94284">how research should be done</a>. Who should conduct it? Who may benefit from or be harmed by it, and who gives consent? And how can the field become more equitable? As an <a href="https://scholar.google.com/citations?user=3QKcZMoAAAAJ&hl=en&oi=ao">archaeologist</a> who partners with geneticists to study <a href="https://theconversation.com/ancient-dna-helps-reveal-social-changes-in-africa-50-000-years-ago-that-shaped-the-human-story-175436">ancient African history</a>, I see both challenges and opportunities ahead.</p>
<h2>Building a better discipline</h2>
<p>One positive sign: Interdisciplinary researchers are working to establish <a href="https://theconversation.com/why-scholars-have-created-global-guidelines-for-ancient-dna-research-169284">basic common guidelines</a> for research design and conduct.</p>
<p>In North America, scholars have worked to address inequities by designing programs that <a href="https://www.singconsortium.org/">train future generations of Indigenous geneticists</a>. These are now expanding to other historically underrepresented communities in the world. In museums, <a href="https://doi.org/10.1073/pnas.1822038116">best practices for sampling</a> are being put into place. They aim to minimize destruction to ancestral remains, while gleaning the most new information possible.</p>
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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>
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<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>
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<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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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">
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<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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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.