A genetic advantage inherited from Neanderthals could give some people a 22% lower risk of severe COVID-19

<p><img src="https://static1.businessinsider.com/image/5e4e9fff0438955586558f24-2400/gettyimages-853018002.jpg" border="0" alt="Neanderthal" data-mce-source="Will Oliver/PA Images/Getty" data-mce-caption="An employee of the Natural History Museum in London looks at model of a Neanderthal male in his twenties, which is on display at the museum's &amp;quotBritain: One Million Years of the Human Story&amp;quot exhibition, September 2014."></p><p></p><bi-shortcode id="summary-shortcode" data-type="summary-shortcode" class="mceNonEditable" contenteditable="false">Summary List Placement</bi-shortcode><p>As an emergency room doctor, Hugo Zeberg has seen first-hand how widely COVID-19 infections can vary in severity. So he started digging for answers in a place that was familiar to him: the genome of Neanderthals.</p><p>Zeberg works at the Karolinska Institute in Sweden, and for the last couple of years, has been studying the degree to which Neanderthalsan extinct human species that died out about 40,000 years agopassed along genes to modern humans through interbreeding.</p><p>Scientists think Neanderthal DNA makes up 1% to 2% of the genomes of many people of European and Asian descent. That small fraction of people's genetic codes may hold important clues about our immune responses to pathogens.</p><p>In a <a href="https://www.pnas.org/content/118/9/e2026309118">study</a> published this week, Zeberg and his colleague Svante Pbo at the Max Planck Institute for Evolutionary Anthropology suggest that some people may have inherited a genetic advantage that reduces their risk of getting severe COVID-19 by 22%.</p><p>The advantage comes from a single haplotypeor long block of DNAon chromosome 12. The same haplotype has been shown to protect people against West Nile, hepatitis C, and SARS (another coronavirus that shares many genetic similarities with the new one, SARS-CoV-2).&nbsp;</p><p>"The protective effect of this haplotype is probably not unique to SARS-CoV-2, but a more general part of our immune system," Zeberg told Insider.&nbsp;</p><h2>Some Neanderthal genes are helpful, others are harmful</h2><p><img src="https://static6.businessinsider.com/image/602d92a631eb0600197c3dc5-2400/2020-04-09t204701z_1_lynxnpeg3828o_rtroptp_4_science-neanderthals.jpg" border="0" alt="FILE PHOTO: Hyperrealistic face of a Neanderthal male is displayed in a cave in the Neanderthal Museum in the northern Croatian town of Krapina February 25, 2010. REUTERS/Nikola Solic/File Photo" data-mce-source="Reuters" data-mce-caption="FILE PHOTO: Hyperrealistic face of a Neanderthal male is displayed in a cave in the Neanderthal Museum in the northern Croatian town of Krapina"></p><p>Zeberg and Pbo found that the Neanderthal-inherited haplotype may have become more common among humans in the last 1,000 years. One possible explanation for this, Zeberg said, is the genes' role in protecting people against other diseases caused by RNA viruses.</p><p>For their new study, the team relied on the genomes of three Neanderthalstwo whose remains were found in southern Siberia and one from Croatia. The DNA dates back 50,000 to 120,000 years. They compared those Neanderthal genomes to the DNA of thousands of people with severe COVID-19.</p><p>The haplotype associated with less severe COVID-19 was found in all three Neanderthal genomes. It codes for proteins that activate enzymes that help degrade RNA viruses.</p><p>However, a prior <a href="https://www.nature.com/articles/s41586-020-2818-3">study</a> from Zeberg and Pbo, published in September, showed that not all Neanderthal DNA confers an advantage. In that research, they found that some modern humans have inherited a haplotype on chromosome 3 that puts them at higher risk of respiratory failure due to COVID-19. That particular gene cluster was found in the Neanderthal from Croatia.</p><p>"If you have that variant, you have twice the risk of getting severely ill with COVID-19perhaps even more," Zeberg said.&nbsp;</p><p>Zeberg's research suggests that around 25% to 30% of people in Europe and Asia carry the protective haplotype, while up to 65% of people in South Asia and 16% of people in Europe carry the dangerous one. Unfortunately, he said, the protective haplotype doesn't offset the risk of the dangerous one for those who have both.</p><h2>Lingering mysteries about how genes influence COVID-19</h2><p><img src="https://static5.businessinsider.com/image/5faeb11d1c741f0019ac9a62-1500/GettyImages-1229588791.jpg" border="0" alt="france covid-19 europe second wave" data-mce-source="Nicolas Tucat/AFP via Getty Images" data-mce-caption="A medical worker swabbs the nose of a man as she administers a novel coronavirus Covid-19 test at a mobile testing unit at the main train station in Marseille, southern France, on November 12, 2020."></p><p>For the most part, people in Africa don't seem to have inherited any genes from Neanderthals.</p><p>"Neanderthals went to Europe and to Asia and lived there before modern humans," Zeberg said. "Then modern humans came 100,000 years ago and they probably mixed 60,000 years ago. So Africa has never met Neanderthals."</p><p>He added, though, that it's possible that Africans inherited other genetic variants from different ancestors that confer their own protection against COVID-19 .</p><p>"There are variants in Africa that we and others are looking into," Zeberg said.</p><p><img src="https://static6.businessinsider.com/image/5fd7c151e00bce00188bb45c-2400/2020-04-27T000000Z1227732581RC27DG9RL6UARTRMADP3HEALTH-CORONAVIRUS-NEW-YORK-LABORATORY.JPG" border="0" alt="covid scientist lab coronavirus testing samples" data-mce-source="Brendan McDermid/Reuters" data-mce-caption="Scientists work in a lab testing COVID-19 samples at New York City's health department, April 23, 2020." data-link="https://www.reutersconnect.com/all'id=tag%3Areuters.com%2C2020%3Anewsml_RC27DG9RL6UA&amp;share=true"></p><p>Scientists still don't know how much of our protection against disease was inherited from ancient ancestors versus acquired more recently. Figuring that out is made more difficult by the fact that part of the Neanderthal genome is still missing.</p><p>But studying ancient genes could still help reveal more about how the body responds to the coronavirus. A <a href="https://www.nature.com/articles/s41586-020-03065-y">December study</a>, for instance, identified eight locations on human chromosomes where particular gene variants were more common among critically ill COVID-19 patients.</p><p>"If we can get a deeper understanding of how our evolutionary history has shaped our immune system, that can be valuable," Zeberg said.&nbsp;</p><p>It's possible, for example, that human ancestors relied on specific genes to protect them from viruses that have since died out. That may explain why certain people's immune systems overreact to the new coronavirus, triggering inflammation that can prove fatal.&nbsp;</p><p>Zeberg said scientists have just started to scratch the surface of these findings.</p><p><a href="https://www.businessinsider.com/neanderthal-genes-lower-risk-severe-coronavirus-2021-2#comments">Join the conversation about this story &#187;</a></p> <p>NOW WATCH: <a href="https://www.businessinsider.com/neanderthal-teeth-reveal-real-paleo-diet-2017-3">50,000-year-old Neanderthal teeth reveal what the real 'paleo diet' was actually like</a></p>
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