About 50 thousand years ago the ancient representatives of Homo sapiens that lived on the territory of modern West Africa apparently intermarried with another group of ancient people, the existence of which is not known scientists.
researchers from the USA found evidence of an ancient “novel” in the genomes of today’s inhabitants of West Africa: representatives of the peoples of Yoruba and Mende. New data can tell a lot about a little-studied part of human history.
for quite some time it was found that people from Europe and Asia are in his DNA “inheritance” of the Neanderthals and the denisovans. These enable someone else’s “code” to indicate that the ancestors of modern humans interbred with other species of hominids. As a result, their offspring inherited those genes, and others. For example, five percent of the genome some people in Papua New Guinea is the legacy of the denisovans. Such a process known as introgression, that is, the acquisition of genes from other species.
the Neanderthals and the denisovans interbred with people who have left Africa — the homeland of modern man. Therefore, the gene of the present inhabitants of Africa contains the least genetic traces of denisovans and Neanderthals.
In a recent study Durvasula Arun (Arun Durvasula) and of Sankararaman Sriram (Sriram Sankararaman) from the University of California in Los Angeles studied the genomes of 405 representatives of the peoples of Yoruba and Mende. The researchers then compared the results with data on the DNA of the Neanderthals and the denisovans. In this they were helped by a computer model, allowing to consider genetic variation that could be obtained from other archaic species of hominids.
as a result, the experts found in the studied samples of DNA segments that did not match the DNA of denisovans and Neanderthals. Scientists came to the conclusion that the DNA belongs to an unknown science ancestor. Because fossils of this mysterious hominid was not found, scientists have dubbed the discovery of the “phantom” DNA from an unknown ancestor.
“I there is no clear definition for this archaic group. That’s why we use the concept of “Ghost.” I don’t think he is particularly closely associated with the groups through which we have received these or other sequences of the genome,” says Sankararaman.
Researchers believe that the crossing occurred about 50 thousand years ago, roughly at the same time when Neanderthals “affair” with representatives of Homo sapiens in other parts of the world.
interestingly, the contents of “phantom” DNA from representatives of the peoples of Yoruba and Mende ranged from 2 to 19 percent.
At the moment there is no data about the role that genetic material plays in the life of modern people, being their carriers.
experts Also found evidence of the same sections of DNA from several people in China. But these cases have not yet been thoroughly studied, but because experts do not make any conclusions.
Note that this is not the first case when the “Ghost” DNA unknown extinct ancestors was discovered in modern humans. Researchers studying the genome of Eurasians, had previously found a legacy of at least three as yet undiscovered ancient hominids in modern human genomes. However, for the first time experts have found something similar in the DNA of modern West Africans.
What genes these “ghosts” could convey and how it could help to survive to the ancient inhabitants of Western Africa, is unknown. As the authors of the new work, detailed understanding of archaic introgression will require analysis of existing and ancient genomes across the continent.
Therefore, the experts intend to continue the study of “gene-ghosts”, to learn more about their role in the life of ancient and modern people.
Scientific article on the results of the study published in Science Advances.