Science News reports: Interbreeding with Neandertals restored some genetic heirlooms that modern humans left behind in the ancient exodus from Africa, new research suggests.

Those heirlooms are versions of genes, or alleles, that were present in humans’ and Neandertals’ shared ancestors. Neandertals carried many of those old alleles, passing them along generation after generation, while developing their own versions of other genes. A small number of humans left Africa around 100,000 years ago and settled in Asia and Europe. These migrants “lost” the ancestral alleles.

But when the migrants or their descendants interbred with Neandertals, Eurasians reinherited the ancestral heirlooms along with Neandertal DNA, John “Tony” Capra reported October 20 at the annual meeting of the American Society of Human Genetics.

Present-day Europeans have more than 47,000 of these reintroduced ancestral alleles, and East Asians — who have more Neandertal ancestry than Europeans (SN Online: 2/12/15) — carry more than 56,000, said Capra, an evolutionary geneticist at Vanderbilt University in Nashville. [Continue reading…]