The first examination of a long-extinct Neanderthal's Y chromosome suggests that fertility problems may have prevented Neanderthal men from successfully mating with modern human females, researchers said Thursday. The study in the American Journal of Human Genetics is based on a male Neanderthal whose 49,000-year-old remains were found in El Sidron, Spain. Until now, researchers have only sequenced the DNA of female Neanderthal fossils, and have found that one to four percent of European and Asian people's DNA can be traced to Neanderthals.
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Study of Neanderthal Y chromosome hints at fertility problems