07/24/.....DNA detectives delving into Neanderthal genom

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DNA detectives delving into Neanderthal genom

BERLIN, Germany (AP) -- U.S. and German scientists launched a two-year project Thursday to decipher the genetic code of the Neanderthal, a feat they hope will help deepen understanding of how modern humans' brains evolved.

Neanderthals were a species that lived in Europe and western Asia from more than 200,000

years ago to about 30,000 years ago. Scientists from Germany's Max Planck Institute for

Evolutionary Anthropology are teaming up with a company in Connecticut to map the genome,

or DNA code.

"The Neanderthal is the closest relative to the modern human, and we believe that by

sequencing the Neanderthal we can learn a lot," said Michael Egholm, a vice president at 454

Life Sciences Corp. of Branford, Connecticut, which will use its high-speed sequencing

technology in the project.

There are no firm answers yet about how humans picked up key traits such as walking upright

and developing complex language. Neanderthals are believed to have been relatively

sophisticated, but lacking in humans' higher reasoning functions.

The Neanderthal project follows scientists' achievement last year in deciphering the DNA of the

chimpanzee, our closest living relative. That genome map produced a long list of DNA

differences between humans and chimps, and some hints about which differences might be

crucial.

The chimp genome "led to literally too many questions, there were 35 million differences

between us and chimpanzees -- that's too much to figure out," Jonathan Rothberg, 454's

chairman, said in a telephone interview.

"By having Neanderthal, we'll really be able to home in on the small percentage of differences

that gave us higher cognitive abilities," he said. "Neanderthal is going to open the box. It's not

going to answer the question, but it's going to tell where to look to understand all of those

higher cognitive functions."

Over two years, the scientists aim to reconstruct a draft of the 3 billion building blocks of the

Neanderthal genome -- working with fossil samples from several individuals.

They face the complication of working with 40,000-year-old samples, and of filtering out

microbial DNA that contaminated them after death.

Only about 5 percent of the DNA in the samples is actually Neanderthal DNA, Egholm estimated,

but he and Rothberg said pilot experiments had convinced them that the decoding was

feasible.

At the Max Planck Institute, the project also involves Svante Paabo, who nine years ago

participated in a pioneering, though smaller-scale, DNA test on a Neanderthal sample.

That study suggested that Neanderthals and humans split from a common ancestor a half-

million years ago and backed the theory that Neanderthals were an evolutionary dead end, not

a direct ancestor of modern humans.

The new project will help in understanding how characteristics unique to humans evolved and

"will also identify those genetic changes that enabled modern humans to leave Africa and

rapidly spread around the world," Paabo said in a statement Thursday.