But it’s one thing to say that Neanderthals interbred with the ancestors of modern Europeans, or that the recently discovered Denisovans interbred with some older mystery group, or that they all ...

The human population may have lingered at about 1,300 for more than 100,000 years, and that population bottleneck could have fueled the divergence between modern humans, Neanderthals and Denisovans.

"When two populations are close to one another but they are very distinct — maybe they can have a different language and different traditions, they are in neighboring territories — they are going to ...