HOMO SAPIENS WANDERED OUT OF AFRICA 50,000 YEARS AGO AND MIXED WITH NEANDERTHALS AND DENISOVANS

When humans first wandered out of Africa more than 50,000 years ago, they soon struggled with strange and hostile surroundings, armed with little more than stone tools. Now a study suggests they got help from an unlikely source: trysts with the neighbors.

Evidence gleaned from DNA shows our species, Homo sapiens, benefited from mixing it up with Neanderthals and another human relative, the Denisovans. Both Neanderthals and Denisovans were well ensconced in other parts of the world when modern humans arrived. By pairing off and having children with these not-quite-human creatures, modern humans quickly acquired DNA that helped them adapt to their new homes, according to a study in this week’s Current Biology.

Mixing with other species “wasn’t just some curious feature of human history,” says study co-author Joshua Akey of the University of Washington in Seattle. "(It) actually had consequences, and it helped our ancestors survive and reproduce.”