This interbreeding between species left an indelible mark that remains present in our current DNA. Between 50,500 and 43,000 years ago, Homo sapiens and Neanderthals shared a unique moment in history.

“Once humans came out of Africa and then encountered archaic species, they might also have encountered their pathogens,” said Rasmus Nielsen, an evolutionary biologist at the University of California, ...

For years, scientists have known that Neanderthals and modern humans interbred, leaving behind genetic traces that still ...

The profusion of breeds today -- at least 150 -- reflects intense, purposeful interbreeding of dogs in the past 150 years. At the same time, the entire history of dogs and their relationship with ...

They say that members of one species couldn't become so different from other individuals through natural variation that they would become two separate non-interbreeding species. One of the most ...