The mating of Neanderthals with other groups of ancient people improved human immunity
Last reviewed: 16.10.2021
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The mating of Neanderthals with representatives of other groups of ancient people played an important role in the formation of the immune system of modern man, American scientists reported in an article published in the journal Science.
They argue that as a result of mixing Neanderthals with the Altai Man (Denisovans), the remains of which were found in the Denisova cave in the Altai in 2008, genes have arisen, which to this day help people cope with different viruses.
Earlier studies indicate that up to 4% of the genome of modern man is due precisely to the pairing of different groups of ancient people. The scientists made their conclusions on the basis of studying the DNA chains taken from our distant ancestors.
In the human immune system, the so-called HLA (human leucocyte antigen) antigens play an important role in protecting against pathogens, such as viruses.
The researchers argue that the origin of some antigens proves that our ancient ancestors had had sexual intercourse with Neanderthals and Altaians for some time.
At least one species of antigen is very often present at present in natives of western Asia, but is rarely found in Africans.
Scientists attribute this to the fact that, after going beyond Africa 65 thousand years ago, an ancient man began to mate with his more primitive species relatives in Europe - unlike those who stayed in Africa.
"The tissue compatibility antigens that Neanderthals and Altaic people had for hundreds of thousands of years adapted to the conditions of life in Europe and Asia, while the newcomers from Africa did not have them," explains Project Manager Peter Parham of Stanford University in California. "And this means that those who received these genes as a result of mating had an advantage over newly arrived relatives."
When the researchers analyzed a variety of HLA-B * 73 antigen present in a modern person, they found evidence that it was acquired as a result of mating with the Altai Man.
Rare material
Neanderthal remains were found in many places in Europe and Asia, but information about the Altai man was obtained only on the basis of studying the remains of a finger and a tooth found in Russia.
"We base our research on the material of a single individual, and it's simply amazing how informative it turned out, and how our data, obtained from the analysis of individual genes, fits into modern genome studies and complements it," points out Professor Parham.
This was also true for tissue compatibility antigens in the Neanderthal genome.
According to scientists, more than half of the varieties of a separate class of HLA from Europeans arose as a result of mating the Neanderthals with the Altaic Man. The Asians have this number even higher - up to 80%, while the inhabitants of Papua New Guinea - up to 95%.
Unequal exchange
Some scientists, not challenging that in the course of evolution different groups of ancient people mixed with each other, express the uncertainty that this process is related to our immune system.
"These conclusions need to be approached with great care, since the antigen system of HLA in modern humans is very diverse," says anthropologist from the American University of Wisconsin-Madison John Hawkes. "Besides, it's very difficult to build ancient genes into this part of the genome. We do not know exactly what the role of these genes was, although we can hypothetically assume that they are, in some way, connected with diseases. "
It is possible that the acquired genes and helped the person in the fight against viruses, but neanderthals mixed with our other ancestors did not save - about 30 thousand years ago they completely disappeared from the face of the earth.
Peter Parham believes that you can draw a parallel between the events of that period and the processes that occurred when the Europeans developed the North and South America.
"Initially, small groups of Europeans explored the new land, overcoming many difficulties and getting to know the local population, but as they grew more and more in the new place, their attitude towards the local tribes became increasingly hostile, they sought to seize their resources and get rid of them from themselves, "says Parham.