Photo: Shannon Stapleton / Reuters
Scientists at the temple University (USA) found that interbreeding between humans and Neanderthals occurred many times. So, group of people, the ancestors of modern European and East Asian populations came in contact with palaeoanthropes at least two times. This was reported in the journal Nature Ecology and Evolution.
According to the generally accepted hypothesis is that the first Homo sapiens appeared in Africa between 200 and 400 thousand years ago. It is believed that the resettlement of people of modern type from the African continent began 177 thousand years ago when they came to the territory of the Levant, to the East of the Mediterranean sea.
At the same time in Eurasia, people were 60-120 thousand years ago, where they met the Neanderthals and denisovans. The genomes of people whose ancestors migrated from Africa, consist of DNA fragments of palaeoanthropes 2-6 percent. While the East Asian populations of this share at 12-20 percent more than the Europeans.
The researchers found that the proportion of Neanderthal DNA in modern European and Asian populations more than should be expected with a single contact between the species. Scientists also analyzed the influence of other possible factors on the incidence of Neanderthal genes in the modern genome, including natural selection, directed against DNA palaeoanthropes, or the genetic contribution of the basal Evrazii, which as a group has been formed before the separation of people on the European and East Asian populations. It turned out that the model several contacts best explains the observed number of Neanderthal genes.
It is known that the denisovans interbred with ancestors of modern humans at least twice, which led to the emergence of two different genetic components in the genome of Homo sapiens. The first spread among Papuans and aboriginal Australians, but bears little resemblance to the genome of the denisovans. The second is found in representatives of East Asian civilization, very similar to the Denisovskaya DNA.
However, such a double genomic structure do not exist in the case of ancestral Neanderthal DNA. This may be due to the fact that, when men began to spread over Eurasia, the Neanderthals were a homogeneous group, and different populations of denisovans had their genetic characteristics.
Video, photo All from Russia.