Barbarian
Member
"The Neanderthals are not totally extinct," said Svante Pääbo, a geneticist at Germany's Max Planck Institute for Evolutionary Anthropology. "In some of us they live on, a little bit."
A tiny bit of genetic variation in humans turns out to be from a different species. That's not unusual in mammals.
Many species, under odd circumstances, will interbreed. But the fact that H. sapiens and H. neandertalis lived for thousands of years in the same area, and showed no interbreeding at all,(Mt. Carmel area in Israel) suggests that some sort of reproductive isolation was in place.