After analyzing the genomes of representatives of West African peoples, scientists found that up to 19 percent of their DNA is made up of genes obtained from unknown extinct hominids.
It is generally accepted that the descendants of a group of people who left Africa interbred with Neanderthals and other related species, receiving some of their genes, while the sapiens who remained in Africa kept the genome "pure". However, new findings make this picture more complex.
More recently, scientists have discovered that backward waves of migrations from Eurasia to Africa brought some Neanderthal genes to the continent. And the authors of a new article, published in the journal Science Advances, have identified traces of genes of a still unknown extinct group of hominids among "purely African" tribes.
Arun Durvasula and Sriram Sankararaman of the University of California, Los Angeles have determined that the genome of the West African Yoruba and Mende peoples contains from two to 19 percent of the DNA obtained from unknown hominids. It is curious that they received these genes, according to scientists, about 24 thousand years ago - at about the same time when the "Europeans" began to return to the continent, bringing some genes of the Neanderthals.
The authors note that some archaeological finds point to the existence of a mysterious group of hominids in Africa. So, some of the remains, dated to 16 thousand years old, show too ancient and primitive features, already uncharacteristic for the inhabitants of the late Stone Age. However, no reliably identified remains of the extinct group have yet been found, and there are still no samples suitable for DNA extraction.
Scientists also looked at the number of mutations accumulated in genes that Africans received from extinct hominids. Based on this, they concluded that their initial separation from our direct ancestors occurred about a million years ago. This figure is in good agreement with the results of a similar study in 2012.
Then scientists discovered that the genome of some modern African peoples carries about two percent of the DNA inherited from unknown hominids who diverged from our ancestors 1, 1 million years ago. However, it is still impossible to say whether we are talking about the same group of extinct relatives, or there were several of them in Africa at that time.