Humans carry Neanderthal DNA we mated about 50,000 years ago according to DNA studies:
http://www.livescience.com/48399-when-neanderthals-humans-first-interbred.html
he DNA from the 45,000-year-old bone of a man from Siberia is helping to pinpoint when modern humans and Neanderthals first interbred, researchers say.
Although modern humans are the only surviving human lineage, others once lived on Earth. The closest extinct relatives of modern humans were the Neanderthals, who lived in Europe and Asia until they went extinct about 40,000 years ago. Recent findings revealed that Neanderthals interbred with ancestors of modern humans when modern humans began spreading out of Africa — 1.5 to 2.1 percent of the DNA of anyone living outside Africa today is Neanderthal in origin.