Were Humans and Neanderthals Swapping DNA Earlier Than We Thought?

Comparison of Modern Human and Neanderthal skulls from the Cleveland Museum of Natural History. (Credit: Wikimedia) We’ve known for years that a lot of us are a little Neanderthal: among non-Africans, Neanderthal genes account for about 1-4 percent of our DNA, the result of interbreeding roughly 47,000-65,000 years ago as modern humans left Africa and moved into Neanderthal territory in Europe and Asia. But a genetic study of multiple individuals, published today in Nature, reveals that Neanderthals interbred with a much earlier wave of human migration, one that left Africa at least 100,000 years ago — about twice as early as we’d thought. Other teams had previously identified a handful of human-occupied sites outside Africa that are older than 65,000 years, such as the Skhul and Qafzeh caves in Israel, but today’s study is the first evidence that our species overlapped with Neanderthals so early. It’s also the first time ...