The only modern humans whose ancestors did not interbreed with Neanderthals are apparently sub-Saharan Africans, researchers say.

New findings suggest modern North Africans carry genetic traces from Neanderthals, modern humanity’s closest known extinct relatives.

Although modern humans are the only surviving members of the human lineage, others once roamed the Earth, including the Neanderthals. Genetic analysis of these extinct lineages’ fossils has revealed they once interbred with our ancestors, with recent estimates suggesting that Neanderthal DNA made up 1 percent to 4 percent of modern Eurasian genomes. Although this sex apparently only rarely produced offspring, this mixing was enough to endow some people with the robust immune systems they enjoy today.

….The researchers say their findings do not suggest that Neanderthals entered Africa and made intimate contact with ancient North Africans. Rather, “what we are saying is that the contact took place outside Africa, likely in the Near East, and that there was a back migration into Africa of some groups that peopled North Africa, likely replacing or assimilating some ancestral populations,” Lalueza-Fox told LiveScience.

This research also suggests that North African groups were not the source of the out-of-Africa migrations. Rather, other groups, perhaps out of East Africa, might have led this diaspora.

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Also – Faces of Our Ancestors – 27 fine model heads depicting the human lineage as so far discovered