When our human ancestors were dispersed From Africa More than 50,000 years ago, they encountered Neanderthals, who already carried some of their genes.
Today, we are the only human species in the world, but that wasn’t always the case. 400,000 years ago, Homo sapiens Although their ancestors lived in East Africa, Neanderthals were already living in Eurasia. It was a world apart, literally, when the only way to get around was by foot. But 50,000 years ago, Homo sapiens Upon arriving in Europe, the Neanderthals disappeared. Was it an unfortunate coincidence? Were they killed by our ancestors? This topic has been debated for a long time.
In 2010, The Neanderthal genome Traces of their DNA have been found in the genomes of modern humans.Maybe you love) Contact with ancient humans continued. Since then, parts of the Neanderthal genome found in modern humans have COVID-19 Susceptibility, Type 2 diabetes,Furthermore autism.
Recent research has reversed this question, Homo sapiens The gene was present in the Neanderthal genome.A new story emerged. Homo sapiens He made several terrifying journeys out of Africa (on foot!) to meet Neanderthals and have children with them.
In the new study, Li-Min Li and colleagues compared the ancestry of 2,000 humans, three Neanderthals, and one Denisovans Researchers sequenced the Neanderthal genome to examine the flow of genetic information between these people over 200,000 years, and found that Neanderthal DNA contains 2.5 to 3.7 percent of our ancestry, a strikingly higher percentage than the 2 percent of Neanderthal DNA found in modern humans.
According to their model, two waves of genetic inflow from humans to Neanderthals predate the last encounter 50,000 years ago: one about 250,000 to 200,000 years ago, and the second about 120,000 to 100,000 years ago, coinciding with the existence of the Nile-Sinai land bridge connecting Africa and Europe. Homo sapiens Arriving in Europe, NeanderthalsTheir descendants and their genomes were likely then assimilated into the Neanderthal population.
Wave Homo sapiens When humans last encountered Neanderthals 50,000 years ago, gene flow changed direction and non-African ancestors assimilated Neanderthal ancestors. It remains an open question whether African gene flow occurred only after this last wave. Future studies of African genetic diversity may help discover further migration patterns within and possibly back to the African continent.
Li and colleagues also Homo sapiens The presence of this element in the Neanderthal genome reduces estimates of the Neanderthal population by about 20%, and the researchers suggest that this small population size may have led to increased interbreeding and the accumulation of harmful mutations that were then passed on to later generations. Homo sapiens.
The small population size means “Neanderthals were probably on the brink of extinction for a very long time,” said Joshua Akey, the study’s lead author. statementRepeatedly encountered Homo sapiens Over 200,000 years, “essentially like waves crashing on a shore, slowly but steadily eroding the coast,” the Neanderthals disappeared into the ocean. Homo sapiens population.
This study Science.
