In the most thorough study to date of the Neanderthal genome, scientists suggest an early human-Neanderthal split. The two species have a common ancestry, say the authors, but do not share much else after evolving their separate ways. The study, published in this week's issue of Science, also finds no evidence of genetic admixture between Neanderthals and humans.
The study helps to explain the evolutionary relationship between Homo sapiens and Neanderthals (Homo neanderthalensis). It also "signifies the dawn of Neanderthal genomics," wrote the study's authors, who comprise scientists from the Lawrence Berkeley (Calif.) National Laboratory, the U.S. Department of Energy Joint Genome Institute (Walnut Creek, Calif.), the University of Chicago (Ill.) and the Max Planck Institute for Evolutionary Anthropology (Leipzig, Germany).
"Humans went through several key stages of evolution during the last 400,000 years," said study c-author Jonathan Pritchard, professor of human genetics who led the University of Chicago team that analyzed the sequencing data. "If we can compare humans and Neanderthals genomes, then we can possibly identify what the key genetic changes were during that final stage of human evolution."
Another author of the Science paper, Svante Pbo of the Max Planck Institute, sequenced Neanderthal mitochondrial DNA in 1997 and first suggested that Neanderthals did not make a substantial contribution to the modern human gene pool. This new study, headed up by Edward Rubin of the Lawrence Berkeley National Laboratory, reinforces that long-debated theory.
"While unable to definitively conclude that interbreeding between the two species of humans did not occur," Rubin said, "analysis of the nuclear DNA from the Neanderthal suggests the low likelihood of it having occurred at any appreciable level."
According to the authors, "If Neanderthal admixture did indeed occur, then [it would] manifest in our data as an abundanc
Contact: Catherine Gianaro
University of Chicago Medical Center