Modern populations acquired important immune system DNA from ancient, cross-species breeding
Sleeping around can expose you to diseases, but, at least in the course of human evolution, it may help you fight ’em. New research suggests that thousands of years ago humans acquired important immune system genes via liaisons with some of our extinct hominid cousins, the Neandertals and Denisovans. These dalliances may have allowed modern humans to persist in regions where unfamiliar pathogens may have otherwise killed them.
Many modern human populations appear to have the same versions of certain immune system genes found in those archaic relatives, a team of researchers reports online August 25 in Science. The Neandertal and Denisovan versions are most prevalent in modern populations in Europe and Asia. Because modern African populations harbor little to none of these archaic gene variants, the discovery suggests that humans acquired them after heading out of Africa and running into Neandertals and Denisovans in Europe and Asia.