DNA Puts Neandertals on Edge of Human Ancestry

Article excerpt

In the ongoing battle over their role in human evolution, Neandertals have taken another hit. An unprecedented amount of genetic material removed from Stone Age fossils indicates that the heavy-boned, beetle-browed Neandertals made, at most, a small genetic contribution to our prehistoric ancestors.

A team led by David Serre of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, compared mitochondrial DNA sequences extracted from fossils of four Neandertals unearthed in Belgium, Croatia, and France with those of five early modern humans found either in the Czech Republic or France. The specimens range in age from around 30,000 to 60,000 years old.

When combined with prior evidence of mitochondrial-DNA differences between Neandertals and Stone Age Homo sapiens (SN: 5/17/03, p. 307), "the data are more supportive of the out-of-Africa hypothesis of human evolution," Serre says. In that scenario, people evolved around 200,000 years ago in Africa and then moved into Asia and Europe, replacing Neandertals and other Homo species.

The new findings buttress the out-of-Africa theory, agrees Christopher Stringer of the Natural History Museum in London, England.

Ancient bones don't often yield mitochondrial DNA, which is located outside the cell nucleus and inherited from the mother, Serre notes. His team successfully obtained only nine genetic samples from 24 Neandertal and 40 early modern-human remains.

Nucleotide sequences of mitochondrial DNA extracted from the four Neandertal specimens resembled comparable genetic sequences previously taken from four other Neandertal fossils, the scientists report in the March Public Library of Science Biology. …