Our ancestors were not a picky bunch. Overwhelming genetic evidence shows that Homo sapiens had sex with Neanderthals, Denisovans and other archaic relatives. Now researchers are using large genomics studies to unravel the decidedly mixed contributions that these ancient romps made to human biology — from the ability of H. sapiens to cope with environments outside Africa, to the tendency of modern humans to get asthma, skin diseases and maybe even depression.
Source: Neanderthals had outsize effect on human biology : Nature News & Comment