According to new genetic research it is suggested that Neanderthals and modern humans interbred about 100,000 years ago, which is much earlier than thought. Some modern humans left Africa long before the ancestors of modern Europeans and Asians migrated out of Africa, scientists added.
Based on the fossil record, Neanderthals diverged from modern humans at least 430,000 years ago. Interbreeding led Neanderthals to contribute genetic material to modern humans outside Africa about 47,000 to 65,000 years ago and researchers have reported that the genetic legacy of the Neanderthal has had a subtle and significant impact on modern human health, influencing risks for depression, heart attacks, nicotine addiction, obesity and other problems.
“We find a rather ancient signal of gene flow from modern humans into the ancestors of Neanderthals from the Altai Mountains in Siberia, suggesting that early modern humans had already migrated out of Africa by the time Neanderthals from Europe moved eastward,” said study co-author Sergi Castellano, an evolutionary biologist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
It is considered that the Neanderthals were once the closest relatives of modern humans, living in Europe and Asia until they went extinct about 40,000 years ago. Scientists discovered that nowadays, about 1.5 to 2.1 percent of DNA in people outside Africa is Neanderthal in origin.
Researchers found that a group of modern humans contributed DNA to the ancestors of Neanderthals from Altai about 100,000 years ago but they did not see this genetic contribution in Neanderthals in Europe, nor in the Denisovan genome.
They noted that the modern human DNA found in the Altai came from a group that diverged from other modern human populations about 200,000 years ago, about the same time when the ancestors of present-day African populations separated. The modern human group that interbred with the Altai Neanderthals later went extinct, and are not among the ancestors of present-day people outside Africa, who left that continent about 65,000 years ago.
It was speculated that the episode of interbreeding they detected may have occurred in the Levant, the eastern Mediterranean region that includes Israel and Syria. Another research suggests that modern humans and Neanderthals were present in the Levant as early as 120,000 years ago. Another potential location for this amazing interbreeding was Southern Arabia and the area around the Persian Gulf.
“The exact place where the gene flow occurred is not settled, but the Near East fits the fossil evidence we currently have,” Castellano told Live Science.