Anthropologists have long speculated that early humans may have mated with Neanderthals, but the latest study provides the strongest evidence so far, suggesting that such encounters took place around 60,000 years ago in the Middle East.
    Small, pioneering groups of modern humans began to leave Africa 80,000 years ago and reached land occupied by the Neanderthals as they spread into Eurasia. The two may have lived alongside each other in small groups until the Neanderthals died out 30,000 years ago.
    Scientists led by Svante [*] took four years to sequence the whole Neanderthal genome from powdered bone fragments taken from three females who lived in Europe 40,000 years ago. To see how similar the Neanderthal was to modern humans, the team compared the ancient DNA with the genomes of five people from France, China, southern Africa, western Africa and Papua New Guinea. The study is the first to attempt a whole-genome comparison between Neanderthals and modern humans.
    The researchers found that modern humans and Neanderthals shared 99.7% of their DNA, which was inherited from a common ancestor 400,000 years ago. Further analysis revealed that Neanderthals were more closely related to modern humans who left Africa than to the descendants of those who stayed. Between 1% and 4% of the DNA in modern Europeans, Asians and those as far afield as Papua New Guinea, was inherited from Neanderthals.
    "Those of us who live outside Africa carry a little Neanderthal in us," said Professor [*] "Neanderthals probably mixed with early modern humans before Homo sapiens split into different groups in Europe and Asia. The comparison of these two genetic sequences enables us to find out where our genome differs from that of our closest relative."
    Interbreeding between humans and Neanderthals may nonetheless have been rare. Just two Neanderthal females in a group of around a hundred humans would have been enough to leave such a trace in our genome, provided that was the group that gave rise to all modern humans outside Africa.
    The study was greeted by scientists as almost certain confirmation that modern humans and Neanderthals mated when the groups crossed paths. "It certainly tells us something about human nature," said Chris Stringer, head of human origins at the Natural History Museum in London.
    Ed Green, a senior author on the study said: "How these peoples would have interacted culturally is not something we can speculate on in any meaningful way. But knowing that there was gene flow is important, and it is fascinating to think about how that may have happened."  The latest study is concerned with ______.