DNA shows humans and Neanderthals had sex

Interesting.

Many modern-day humans may be carrying around a fragment of Neanderthal DNA on one of their sex chromosomes, a new study finds.

The research adds a piece of corroborating evidence to the theory that Neanderthals and humans interbred sometime after humans migrated out of Africa between 50,000 and 80,000 years ago. The DNA fragment, found on the human X chromosome, is present in 9 percent of humans across the world from Asia to Europe to America — except in Africa, where it does not appear.

"It's in the Middle East, it's in Europe, it's in Eurasia, it's in America, it's in Australia," study researcher Damian Labuda of the University of Montreal told LiveScience. "This one event which led to this on the human X chromosome has to occur very early after modern man left Africa."