Breeding with Neanderthals helped humans go global

WHEN the first modern humans left Africa they were ill-equipped to cope with unfamiliar diseases. But by interbreeding with the local hominins, it seems they picked up genes that protected them and helped them eventually spread across the planet. The publication of the Neanderthal genome last year offered proof that Homo sapiens bred with Neanderthals after leaving Africa. There is also evidence that suggests they enjoyed intimate relations with other hominins including the Denisovans, a species identified last year from a Siberian fossil. But what wasn't known is whether the interbreeding made any difference to their evolution. To find out Peter Parham of Stanford University in California took a closer look at the genes they picked up along the way.  link