sub-Saharan Africans to be slightly more closely related to Neanderthals than to Denisovans.24 This must reflect another example of interbreeding we didn’t know about. The pattern we observed could only be explained by Denisovan interbreeding with a deeply divergent, still unknown archaic population—one from which Africans and Neanderthals have little or no DNA, and which separated from the common ancestors of modern humans, Neanderthals, and Denisovans well before their separation from each other.
