Ann GibbonsNeanderthals have long been seen as uber-masculine hunks, at least compared with their lightweight human cousins, with whom they competed for food, territory, and mates.
But a new study finds Homo sapiens men essentially emasculated their brawny brethren when they mated with Neanderthal women more than 100,000 years ago.
Those unions caused the modern Y chromosomes to sweep through future generations of Neanderthal boys, eventually replacing the Neanderthal Y.The new finding may solve the decade-old mystery of why researchers have been unable to find a Neanderthal Y chromosome.
Part of the problem was the dearth of DNA from men: Of the dozen Neanderthals whose DNA has been sequenced so far, most is from women.