February 12, 2009

Neanderthal Genome Mapped Out By Scientists

Scientists said Thursday that they have mapped a first draft of the Neanderthal genome, which might reveal the links between modern humans and their prehistoric cousins.

Researchers used DNA fragments extracted from three Croatian fossils to show over 60 percent of the entire Neanderthal genome and sequencing three billion bases of DNA.

"The Neanderthal genome sequence will clarify the evolutionary relationship between humans and Neanderthals as well as help identify those genetic changes that enabled modern humans to leave Africa and rapidly spread around the world," Germany's Max Planck Institute for Evolutionary Anthropology said in a press release.

"These DNA sequences can now be compared to the previously sequenced human and chimpanzee genomes in order to arrive at some initial insights into how the genome of this extinct form differed from that of modern humans."

The last common ancestor of Neanderthals and humans lived about 660,000 years ago, according to the researchers.

Neanderthals are believed to be the hominid form that is the most closely related to present-day humans, although the precise relationship remains unclear.

The Neanderthals lived in parts of Europe, Central Asia and the Middle East for around 170,000 years, but their last known refuge was Gibraltar about 28,000 years ago.

Reasons for why they died out is a matter of debate, because they did once co-exist alongside modern man.

Some say that Neanderthals were wiped out slowly by the smarter Homo sapiens in the competition for resources.

Others say that interbreeding took place, which implies that we could have Neanderthal heritage in our genome today.

Svante Paabo, the lead researcher, has organized a consortium of researchers from around the world to help analyze the Neanderthal genome.

A number of genes will be examined that have been identified as part of the role of recent human evolution, including those implicated in brain aging and development, which have been suggested to have come from Neanderthals.

"The preliminary results suggest that Neanderthals have contributed, at most, a very small fraction of the variation found in contemporary human populations," the institute said.


Image 1: Svante Pääbo holding a Neandertal skull © Max Planck Institute for Evolutionary Anthropology

Image 2: In 1980 the 38,000-year-old bone of a Neandertal was found in the Vindija Cave (Croatia). Max Planck researchers have now sequenced his complete mitochondrial genome. © Max Planck Institute for Evolutionary Anthropology


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