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Researchers believe they have discovered the date of the first sexual encounter of our ancestors “Homo Sapiens” outside Africa, about 300 thousand years ago, having fathered children with Neanderthals, who lived in the area that currently corresponds to Europe.
A team of international researchers analyzed the remains of three Neanderthals, including the skull of a baby who died in Russia 44,000 years ago and an adolescent of the same ancestral species as today’s humans prevailing in Europe, found in the Asturian cave of El Sidron. , in Spain, who died 49,000 years ago.
The researchers focused on the male remains because they wanted to analyze the Y chromosome, the genetic mark of fatherhood that is passed from father to son. They intended to understand who had children with whom: if it was the sturdy Neanderthal males that mated with the sapiens females, if the elegant sapiens males that sought out Neanderthal females to have children.
The results, published in the magazine “Sapiens”, revealed a new chapter of the cross between sapiens and Neanderthals, now extinct, occurred about 300 thousand years ago.
It is the oldest known cross between species, having occurred even before our species is what it is, since Homo Sapiens itself appeared about 200,000 years ago, approximately 100,000 years after this “first encounter”. sexual “between two of the three species of hominids that inhabited the earth 300,000 years ago.
Carles Lalueza-Fox, geneticist and co-author of the study, believes that the evidence of this cross, marked on the Y chromosome, proves that there was a migration out of Africa of the ancestors of Homo sapiens, who reunited with Neanderthals in a unidentified place.
“It is impossible to know where it happened, but the most plausible thing is that it was in the Middle East or, less likely, in the Balkans,” argues Antonio Rosa, another co-author of the study, quoted by the Spanish newspaper “El País”.
The research, focused on the Y chromosome, shows that males and females of both species, sapiens and Neanderthals participated in this encounter, but that it left a permanent mark on the species that was prevalent in Europe at that time: the Y chromosome of Neanderthals was replaced by those of the sapiens. , possibly because Neanderthals were far fewer, about 10,000 at the time.
Another previous study had already shown that the maternal genetic mark of Neanderthals, the mitochondrial genome passed from mother to child, was Sapiens, meaning that a cross between species left the mark of female Sapiens on Neanderthals.
Researchers place this cross at an identical date to that of male Sapiens with Neanderthal females, 300,000 years ago. Most likely, it all happened at the same meeting, admits Mikkel Schierup, a researcher at the University of Aaruhs in Denmark.
In this encounter now identified by scientists, and seen as the first cross between species outside of Africa, it was the sapiens who passed on the genes to the Neanderthals, the opposite of what happened some 50 thousand years ago, when the opposite happened.
This new study updates and tangles our family tree. Taking into account only the sex chromosomes of the fathers and the mitochondrial genome of the mothers, Sapiens and Neanderthals are the closest relatives. By analyzing the rest of the non-sexual DNA, Neanderthals are closer to Denisovans, a mysterious people that lived in Asia, at a time when the earth was inhabited by six different species of hominins.
Analysis of previous studies has shown that the three best-known species, Neanderthals, sapiens and Denisovans, met at various times in history and had children among them. Until this new study, sapiens and Neanderthals were thought to have interbred twice, once about 100,000 years ago, possibly in the Middle East, and another 50,000 years ago.
From these encounters, mestizo children were born who, according to the researchers, were welcomed by the tribes and raised as if they were their own species. They grew, they multiplied for thousands of years, to the point that today there is only one species of man, the sapiens.
As a result of these encounters between the three species, thousands of years ago, many modern humans have a percentage of Neanderthal DNA and, to a lesser extent, Denisovan.
Neanderthals and Denisovans were extinct thousands of years ago, but somehow they are still alive among us. All human beings outside of Africa have about 2% active Neanderthal DNA in each of their cells. Some Australian and New Guinea sapiens have a hint of Denisovan DNA.
In addition, some peoples of Africa and India have DNA marks of “ghost towns”, human species to be identified, but whose mark remains in humans today thousands of years later.
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