Now scientists have found evidence of interbreeding between humans and another extinct hominoid group in Africa.
"The populations that interbred in Africa were on a similar scale of divergence as the expanding modern population and Neanderthals were outside of Africa," Hammer said. "They were similar enough biologically so that they were able to produce fertile offspring, thus allowing genes to flow from one population to the other."
The length of the exotic haplotypes from this extinct lineage suggests interbreeding might still have occurred until as recently as 35,000 years ago.
"We think there were probably thousands of interbreeding events," Hammer said. "It happened relatively extensively and regularly."Your family tree just got a whole lot weirder.