Human evolution; Africa has a Neanderthal mixture (Introduction)

by David Turell , Thursday, January 30, 2020, 20:28 (1548 days ago) @ David Turell

Just discovered, and a result of migrations between Africa and Europe:

https://www.sciencenews.org/article/new-genetic-analysis-reveals-modern-africans-have-s...

"People who migrated out of Africa around 60,000 to 80,000 years ago interbred with Neandertals. That set the stage for some human groups to return to Africa carrying Neandertal genes that spread throughout the continent, apparently because those genes proved beneficial to ancient Africans, researchers report January 30 in Cell.

"Sets of Neandertal gene variants inherited by modern Africans include genes involved in bolstering the immune system and modifying sensitivity to ultraviolet radiation, geneticist Joshua Akey of Princeton University and his colleagues found. Those genes presumably spread quickly once introduced to African humans. A new statistical approach for detecting ancient genetic material that’s still present in modern DNA, developed by Akey’s team, enabled this discovery. (my bold)

"The researchers’ new technique also detected a human journey out of Africa roughly 100,000 to 150,000 years ago that led to the introduction of human genes into Neandertals via interbreeding. Some African DNA that appeared at first to have been inherited from Neandertals actually came from those ancient humans when scrutinized more closely, the investigators say.

“'Our work highlights how humans and Neandertals interacted for hundreds of thousands of years, with populations dispersing out of and back into Africa,” Akey says. “Remnants of Neandertal DNA survive in every modern human population studied to date.”

***

"Neandertal DNA accounts for, on average, about 0.5 percent of individual Africans’ genetic inheritance, or genome, far more than reported in earlier studies, Akey’s team concludes. Most present-day people outside Africa carry about three times as much Neandertal DNA as Africans do, the researchers say. More than 94 percent of Neandertal DNA sequences detected in today’s Africans have also been observed in non-Africans, they say."

Comment: the presence of different Homo species developed advantages for the final sapiens results as noted in the story ab out better immunity and better protection from the sun.