A team of researchers was able to give dates for the encounter between our ancestors – Homo Sapiens – and Homo Neanderthal. Mathilde Fontez, editor-in-chief of the magazine Epsilondeciphers the work of these geneticists who retraced their exchanges.
franceinfo: The first exchanges date back 50,000 years?
Mathilde Fontez : 7,000 years is what these researchers find. For 7,000 years, our human ancestors interacted with Neanderthals. For 7,000 years, the two species met, mixed, formed mixed couples, gave birth to hybrids, crossbreeds. In short, for 7,000 years, the two species co-evolved.
The encounters began 47,000 years ago, and they lasted until the disappearance of Neanderthals. And Homo Sapiens continued its expansion, exploring all the territories of the world, until today, en keeping 1 to 2%, in its chromosomes, of the genes transmitted by Neanderthals.
Was it from these genes that we were able to trace the chronology?
Yes, researchers have traced gene flow. They compared the genome of modern humans to those of ancient humans: they brought together the analyzes of 59 individuals who lived more than 2,200 years ago, up to 45,000 years for the oldest.
It is this global study which allowed them to gain in precision, compared to the dating deduced from all the archaeological traces: Neanderthal bones, tools, etc., and to reconstitute the story: this love story between two species.
Including when it goes wrong: the areas of our genome, devoid of Neanderthal genes, show that certain Neanderthal characteristics must have been fatal for Sapiens: certain hybrids were not viable. 70% of the Neanderthal genome was eliminated very quickly, in a sort of genetic lottery.
We kept a lot of Neanderthals?
We didn't keep his big bump on his forehead, nor his enormous muscles, nor his very large eyes, mbut we kept his immunity, sProtective genes against parasites and fungi. But alsoa resistance to the ancestors of influenza A, hepatitis C, coronaviruses, shas lipid assimilation capacity. The pigmentation of its skin, adapted to the northern sun, its resistance against the cold.
Neanderthals were there, in Asia, in Europe, for a very long time before us, for 300,000 years. He had become accustomed, generation after generation, to the harsh climate and the microbes. This study confirms that it probably helped us adapt when we left Africa to venture north. Without this history with Neanderthals, we might not have survived.
