By Bruce Bower
An ancient, humanlike population still undiscovered in fossils left a genetic legacy in present-day West Africans, a new study suggests.
These extinct relatives of Homo sapiens passed genes to African ancestors of modern Yoruba and Mende people starting around 124,000 years ago or later, say UCLA geneticists Arun Durvasula and Sriram Sankararaman. Surviving DNA of those ancient hominids is different enough from that of Neandertals and Denisovans to suggest an entirely different hominid was the source.
Yoruba and Mende groups’ genomes contain from 2 to 19 percent of genetic material from this mysterious “ghost population,” the scientists report February 12 in Science Advances. Some DNA segments passed down from the mysterious Homo species influence survival-enhancing functions, including tumor suppression and hormone regulation. Those genes likely spread rapidly among modern West Africans, the investigators suspect.
DNA from Han Chinese in Beijing as well as Utah residents with northern and western European ancestry also showed signs of ancestry from the ancient ghost population, Durvasula and Sankararaman found. But DNA from those two groups was not studied as closely as that from the Yoruba and Mende people.