No Neanderthal Ancestors for Modern Humans

If ancient homo sapiens got it on with their Neanderthal cousins, there were no children to show for it. Researchers studying Neanderthal DNA have sequenced half of the Neanderthal genome, and shoot down the theory that European humans interbred with the now-extinct species. And the team says the genome has other things to teach us about Neanderthal life, including their sexual proclivities.

The research team at the Max Planck Institute for Evolutionary Anthology presented their findings last week at a human evolution conference. The researchers have compared the Neanderthal genome to that of modern humans of European and African descent. Because Neanderthals and modern humans coexisted in Europe, researchers have theorized that European genomes would have more similarities with the Neanderthal genome than would African genomes. However, European and African genomes have a similar number of differences from the Neanderthal genome, suggesting that modern humans in Europe outbred rather than assimilated the Neanderthals.

Earlier comparisons of mitochondrial similarly cast doubt on the Neanderthal interbreeding theory, but recent research has revealed that Neanderthals do not possess the very genes some researchers believed modern humans had received from Neanderthals. Neanderthals possess neither the microcephalin gene, linked to bulging brains in humans, nor humans’ increased fertility gene.

The team is planning to publish a rough draft of the Neanderthal nuclear genome, and hopes that a closer study of the genome will reveal more about the Neanderthal history. They believe, for example, that further analysis of the available genome will reveal whether Neanderthal practiced polygyny, with fewer males breeding with proportionally more females. But the study is hampered by the poor quality and small sample of available genetic samples, and the researchers say it will be another year or two before an adequate sequencing is complete.

[New Scientist]