When Neanderthals and early humans shared Eurasia for over 35,000 years, they had sex far more often than scientists first imagined, a new research suggests.

Researchers from Temple University explained what had happened more than 75,000 years ago when early humans left Africa and explored Europe and Asia where they started to mingle with Neanderthals. As established, most humans nowadays have about 2 percent of Neanderthal DNA, a proof of what is passed down after the interbreeding took place ages ago.

Those who do not have Neanderthal genes were probably because their ancestors were not with the group who traveled into other parts of the world, meaning, they just stayed in Africa. Interestingly, people from East Asia have 12 to 20 percent more Neanderthal DNA than those from Europe, which strongly suggested the multiple times of interbreeding between early humans and Neanderthals.

Other experts still believe that small percentage of Neanderthal genes, which still has an effect on today's immune system and the development of diseases present in modern-day humans, was a product of just a one-time encounter. Prior to the recent findings, the frequency of interbreeding among the two species was unclear.

Study Using AI

Researchers Joshua Schraiber and Fernando Villanea, whose hypothesis explained that different species that stayed over a certain area for a period of time had sexual encounters, tried to see if their guess was right. With artificial intelligence, they found that, indeed, varying DNA patterns is a result of multiple times of interbreeding between East Asians, Europeans, and Neanderthals.

"These findings indicate a longer-term, more complex interaction between humans and Neanderthals than was previously appreciated," Schraiber explained.

Oase 1's Skull

Another proof of the frequent interbreeding was the skull that belonged to Oase 1, which was unearthed from Romania 16 years ago. The cranium, which is about 37,000 to 38,000 years old, showed it had Neanderthal ancestors. This means there was interbreeding just less than 40,000 years ago.

This study clarified what people had initially thought of Neanderthals. These species that were classified in 1864 were perceived to have failed in mating but was debunked by the latest study on interbreeding. Also, about 50,000 years ago, Neanderthals living in France reportedly knew how to start a fire.

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