Demographic history and genetic differentiation in apes

Analysis of one million base pairs of Neanderthal DNA

Neanderthals are the extinct hominid group most closely related to contemporary humans, so their genome offers a unique opportunity to identify genetic changes specific to anatomically fully modern humans. We have identified a 38,000-year-old Neanderthal fossil that is exceptionally free of contamination from modern human DNA. Direct high-throughput sequencing of a DNA extract from this fossil has thus far yielded over one million base pairs of hominoid nuclear DNA sequences. Comparison with the human and chimpanzee genomes reveals that modern human and Neanderthal DNA sequences diverged on average about 500,000 years ago. Existing technology and fossil resources are now sufficient to initiate a Neanderthal genome-sequencing effort.

Archaic admixture in the human genome

One of the enduring questions in the evolution of our species surrounds the fate of 'archaic' forms of Homo. Did Neanderthals go extinct without interbreeding with modern humans 25-40 thousand years ago or are their genes present among modern-day Europeans? Recent work suggests that Neanderthals and an as yet unidentified archaic African population contributed to at least 5% of the modern European and West African gene pools, respectively. Extensive sequencing of Neanderthal and other archaic human nuclear DNA has the potential to answer this question definitively within the next few years.