Interesting article from Alasdair Wilkins on io9.com:
The evidence has been mounting for years that early humans and Neanderthals interbred, but now it’s pretty much a certainty. Part of the X chromosome found in people from outside Africa originally comes from our Neanderthal cousins.
It’s kind of amazing to think that, as recently as just a few years ago, the scientific consensus was that humans and Neanderthals were completely separate species and probably didn’t interbreed. Since then, a ton of new evidence has come to light to change that position, and now new research from Damian Labuda of the University of Montreal more or less completes this big reversal.
Neanderthals, one of the last extant hominid species other than our own, left Africa somewhere between 400,000 and 800,000 years ago and settled mostly in Europe until they went extinct 30,000 years ago. Early modern humans left Africa about 80,000 to 50,000 years ago, meaning they overlapped with Neanderthals in time and place for at least 20,000 years.