Genetic heritage: scientists have discovered the DNA of Neanderthal “cousins” in modern humans
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Scientists have found the genes of the “cousins” of Neanderthals – Denisovans – in the DNA of modern humans. Their genetic information affects our fertility, immune system and even how the body coped with the COVID-19 virus, reports AP. Denisovans were relatives of Homo sapiens, they lived next to each other, gave birth to children, and accordingly their genes mixed. Until recently, the genetic heritage of ancient people was invisible. Scientists were limited to what they could get from the shape and size of the bones. Photo: deosum/Depositphotos But Nobel laureate Svante Paabo was the first to dissect the Neanderthal genome and initiate a series of ancient DNA studies. He also discovered a hominin named “Denysov Man”. Recent research shows that some African populations have almost no Neanderthal DNA. And representatives of European or Asian origin have from 1% to 2%. Denisovan DNA is barely visible in most parts of the world, but makes up 4% to 6% of the DNA of people in Melanesia, a region northeast of Australia that stretches from New Guinea to the Fiji Islands. Dr. Hugo Seeberg of the Karolinska Institute in Sweden noted that this may seem like a small number, but there were once only a thousand Neanderthals. “Half of the Neanderthal genome still exists, in small pieces scattered around modern humans,” he added. Therefore, the Denisovan genome probably also has a significant impact on modern humans. For example, Neanderthal DNA has been linked to autoimmune diseases such as Graves’ disease and rheumatoid arthritis. Researchers note that when Homo sapiens left Africa, they did not have immunity to diseases in Europe and Asia, but the Neanderthals and Denisovans who already lived there did. “By interbreeding with them, we quickly fixed our immune system, which was good news 50,000 years ago. Some people have an oversensitive immune system that turns itself on,” said Chris Stringer, a researcher on human evolution at the Natural History Museum in London. Another scientist, Rick Potts, said that in a similar way, a gene related to blood clotting, which is believed to have been passed down from Neanderthals in Eurasia, may have been useful around 12,000 years ago. A gene related to blood clotting was probably passed down from Neanderthals in Eurasia. It may have been useful in a harsh world about 12,000 years ago, but now the gene may increase the risk of stroke in the elderly. In 2020, research by Seeberg and Paabo found that the main genetic risk factor for severe COVID-19 was inherited from Neanderthals. “We compared it with the Neanderthal genome, and it had a complete match,” the scientist said. Subsequently, researchers discovered that the set of Denisovan DNA in the chromosome, on the contrary, protected people from a severe form of COVID. The same goes for genes responsible for skin and hair, behavioral traits, skull shape, type 2 diabetes, and even high sensitivity to pain. The presence of the Denisovan gene is also associated with an effect on metabolism and better adaptation to high altitudes. In particular, it was found in Tibetans who adapted to living and developing in an environment with a lower oxygen content. Read also: Neanderthals were cannibals: scientists found new confirmation
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