Scientists map Neanderthal genome

15th February 2009, Comments 0 comments

They will examine a number of genes that have been identified as playing a role in recent human evolution, including those implicated in brain aging and development that have been suggested to have come from Neanderthals.

Chicago -- In a development that could reveal how modern humans evolved differently than our closest prehistoric cousins, scientists have mapped a first draft of the Neanderthal genome.

"Studying the Neanderthal genome will tell us what makes modern humans really modern and really human," said Jean-Jacques Hublin of Germany's Max Planck Institute for Evolutionary Anthropology last week. "Why we are alone, why we have these amazing capacities that drove our ancestors to draw, paint" and develop complex tools, he said at a press conference.

Researchers used DNA fragments extracted from three Croatian fossils to map out more than 60 percent of the entire Neanderthal genome by sequencing three billion bases of DNA.

The analysis showed that it is highly unlikely that much interbreeding occurred as there was "very little, if any" Neanderthal contribution to the human gene pool, said lead researcher Svante Paabo of the Max Planck Institute.

But it also revealed that our Neanderthal cousins may have been closer to us than we thought: they share a gene that plays a key function in speech and language.

"How human were they and how would they have interacted?” Paabo asked. “We probably will never fully know. They are not very different from us from a genomic perspective."

Neanderthals and modern humans shared a common ancestor from which they diverged about 300,000 years ago.

The squat, low-browed Neanderthals lived in parts of Europe, Central Asia and the Middle East for around 170,000 years but traces of them disappear some 28,000 years ago. Their last known refuge was Gibraltar.

Why they died out is a matter of furious debate because they coexisted alongside modern man.

Some argue the smarter Homo sapiens slowly wiped out Neanderthals in the competition for resources.

Others contend that the Neanderthal traits disappeared through interbreeding.

Paabo said the Neanderthal genome project will help answer why humans triumphed by "finding evidence of positive selection, of where something changed in our ancestors that really made a difference in how we reproduced and survived."

It will also allow researchers to identify which changes occurred in the human genome prior to divergence from Neanderthals and which occurred afterwards.

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

They will examine a number of genes that have been identified as playing a role in recent human evolution, including those implicated in brain aging and development that have been suggested to have come from Neanderthals.

Results are expected to be published later this year.

AFP/Expatica

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