Tuesday, June 1, 2010

Neanderthal DNA

An international team of scientists from the Department of Evolutionary Genetics at the Max-Planck Institute for Evolutionary Anthropology at Leipzig, Germany, reported a draft sequence of the Neanderthal Genome – the full complement of genes. Neanderthals lived in Europe some 30,000 to 45,000 years ago and in the Middle East some 80,000 years ago. This species did, in fact coexist with modern humans.

The Neanderthal DNA that was analyzed was harvested from three female Neanderthals that lived in Croatia approximately 38,000 years ago. Although an extraordinary amount of DNA has been successfully defined, about one-third of the genome remains ambiguous. The investigators, however, devised a novel technique to fill in these “gaps.” The scientists involved in this extensive undertaking then compared the Neanderthal-derived data to the DNA obtained from five individuals from distinct parts of the world. The results of these studies yielded some surprising conclusions.

They found that the Neanderthal and modern human genomes are 99.84% identical to each other, and that those regions of the DNA that are different represent those genes that have been modified since the human species diverged from Neanderthals estimated to have occurred between 270,000 and 444,000 years ago. Furthermore, the genetic areas that differ seem to involve genes that play a role in skin, metabolism, the skeleton and the development of higher order brain function.

The most surprising result of all was the discovery that both Europeans and Asians share from 1% to 4% of their DNA with Neanderthal DNA, whereas Africans do not. This result is strongly suggestive of interbreeding between modern humans after they emerged from Africa and Neanderthals.

These data shed some new interesting light on human evolution. It has become increasingly clear that the analysis of DNA of humans and other species is an important and often essential tool in the study of the evolutionary process.

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