Genealogy of Neanderthals
The late Neanderthals turned out to be guardians of "racial purity"
Researchers from Germany using a new technique were able to analyze the DNA of five Neanderthals who lived 39-47 thousand years ago. It turned out that modern humans (except for the inhabitants of Black Africa) interbred with late Neanderthals of European origin, but did not have sexual contacts with the older Altai Neanderthals. But the most surprising thing turned out to be that there are no traces of contacts with modern humans in the DNA of the Neanderthals themselves. It is still impossible to explain this mysterious result. The corresponding article is published in Nature (Hajdinjak et al., Reconstructing the genetic history of late Neanderthals).
Previously, scientists have achieved successful DNA analysis of Neanderthals in only four cases. The reason was that for tens and hundreds of thousands of years, DNA from the bones of these ancient people was contaminated with the genes of bacteria and the anthropologists themselves who discovered the bones. In the new work, the authors used pretreatment of samples with hypochlorites (a strong oxidizer) to eliminate surface contamination to obtain uncontaminated Neanderthal DNA, and then ground nine milligrams of Neanderthal bone or tooth tissue into a fine powder and analyzed DNA already from it.
They managed to obtain comprehensive data on the genomes of five individuals who lived on the territory of modern Belgium, France, Croatia and Russia from 39 to 47 thousand years ago. It turned out that the Neanderthal genes present in modern Caucasians and Mongoloids (native Africans do not have them) originate from a group of European Neanderthals, to which all five studied individuals belonged. The previously studied genomes of Neanderthals from Altai belong to completely different groups. At the same time, Altai Neanderthals have not interbred with the ancestors of late European Neanderthals for at least 150,000 years.
The most unexpected result of the work was that all five studied Neanderthals did not have any admixtures of the genes of modern humans. At the same time , most of the currently living representatives Homo sapiens from 3 to 8 percent of the genome is the legacy of late Neanderthals, close to the five studied individuals. This means that somehow the gene transfer between the two species was one-sided. This is a truly surprising situation, since usually the mixing of genes is observed in the descendants of both interbreeding groups.
The reasons for the detected oddity are not entirely clear. Perhaps the explanation lies in the field of some "cultural" features and customs. For example, Neanderthals could kill half-breeds after birth, and Homo sapiens, on the contrary, left them in the tribe. Another option, concerning the controversial theory of the destruction of Neanderthals by militant and aggressive people of the modern type, involves the capture and captivity of female Neanderthals, which our relatives themselves did not practice.
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