DNA extracted from the remains found in a Bulgarian cave by three people who lived about 45,000 years ago reveals surprises about some of the first populations of Homo sapiens to enter Europe, including extensive crossbreeding with Neanderthals and genetic links to today’s East Asians.
Scientists said Wednesday that they had sequenced the genomes of the three men, all men, using DNA obtained from molar and bone fragments discovered at Bacho Kiro Cave near the town of Dryanovo, as well as a woman who lived about 35,000 years ago.
Homo sapiens first appeared in Africa about 300,000 years ago and later traveled to other parts of the world, sometimes encountering Neanderthals – close relatives of homo sapiens – who already inhabit parts of Eurasia. The three men from the Bacho Kiro cave represent the oldest persons with certainty dated Homo sapiens from Europe.
They had 3% to 3.8% Neanderthal DNA and had Neanderthal ancestors of about five to seven generations in their family history, which is evidence of crossbreeding, said geneticist Mateja Hajdinjak of the Francis Crick Institute in London, lead author of the study. Nature.
A crossover, known as an adjunct, between homo sapiens and Neanderthals before the extinction of Neanderthals just over 40,000 years ago, with today’s human populations outside Africa carrying a small percentage of Neanderthal DNA, is shown above.
The prevalence of this crossover and the dynamics of the relationship and power between Homo sapiens and Neanderthals are more difficult to understand, including any role that Homo sapiens played in the decline of Neanderthals. A new study suggests that crossbreeding was more common than was previously known for the first Homo sapiens in Europe.
“It’s an amazing observation” that all three individuals had Neanderthal ancestors in recent family history, said geneticist and co-author of the study Svante Pääbo, director of the Max Planck Institute for Evolutionary Anthropology in Germany.
“This makes it likely that the earliest modern humans often mingled with Neanderthals when they met. Perhaps even the case that part of the reason Neanderthals disappeared is that they were simply absorbed into larger modern human groups. That may be just part of the reason why have disappeared, but the data supports such a scenario, ”Pääbo said.
Researchers have discovered a genetic contribution among today’s people from the group that included these three, but it was unexpectedly determined that it was especially in East Asia, including China, and not in Europe. This suggests that some people from this group eventually headed east.
“This study redirected our previous understanding of early human migration to Europe in a way that showed how even the earliest history of modern humans in Europe could have been turbulent and involved population replacement,” Hajdinjak said.
The notion of population replacement was illustrated by the fact that a 35,000-year-old person from the Bacho Kiro cave belonged to a group that was not genetically related to the earlier inhabitants of the site.
Another study published Wednesday in the journal Ecology and evolution of nature shed more light on the early European populations of Homo sapiens.
The scientists sequenced the genome of the female person homo sapiens using DNA extracted from a skull found at a site southwest of Prague in the Czech Republic. It is thought to have lived more than 45,000 years ago, although efforts to find radiocarbon to establish a firm date have been unsuccessful.
This woman carried 3% of Neanderthal descent and had genetic traits that suggest she had dark skin and dark eyes, said geneticist Kay Prüfer of the Max Planck Institute for Evolutionary Anthropology, lead author of the study.
“Her skull shows evidence of predator milling, possible hyenas,” Prüfer said.
Her group, different from the one in Bulgaria, seems to have become extinct without leaving a genetic lineage among modern humans.