Wednesday, November 15, 2006

Neanderthal DNA decoded

Using a 38,000-year-old bone fragment found in a Croatian cave, scientists have decoded a section of DNA from humanity's closest related species ? the long extinct and enigmatic Neanderthal.

cavecroatia.jpgSo far, researchers have sequenced only about 1 million out of an estimated 3 billion base pairs of the Neanderthal genome. They expect it will take two years to complete a full draft.

The reports, to be published concurrently Thursday in the journals Nature and Science, demonstrate the feasibility of squeezing genetic information out of fossils ? a new way of probing the ancient past that until now has been glimpsed primarily through scattered bones and artifacts.

For more than 100,000 years, Neanderthals lived throughout Europe and western Asia but died out shortly after modern humans began to push their way north from Africa about 40,000 years ago.

"They disappeared from the fossil record from the planet about 28,000 to 30,000 years ago," said Edward Rubin, director of the genomics division at Lawrence Berkeley National Laboratory and senior author of the report in Science. "The sequence data will serve as a DNA time machine that will tell us about biology and aspects of Neanderthals that we could never get from their bones."

The preliminary sequences contain enough information to calculate that Homo neanderthalis and Homo sapiens shared at least 99.5% of their DNA. All the characteristics that make humans unique are contained in the remaining 0.5%.

The two species last shared a common ancestor about 700,000 year ago. Significant mixing between ancestors of Neanderthals and humans ended about 370,000 years ago, according to Rubin's group. - latimes

Interesting. Recall this study from 2003:
One study "found that 99.4 percent of the most critical DNA sites are identical in the corresponding human and chimp genes. With that close a relationship, the two living chimp species belong in the genus Homo, says Morris Goodman of Wayne State University in Detroit." - newsci

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