DNA yields secrets of Neanderthals

BY STEVE CONNOR
14 February 2009
New Zealand Herald
English
(c) 2009 The New Zealand Herald

Scientists say clues in fossils point to similarities with modern man.

Their lives may have been nasty, brutish and short but their DNA has survived long enough to be almost fully decoded in a pioneering study that has revealed just how closely related Neanderthals were to modern humans.

For the first time, scientists have deciphered the genetic sequence of the Neanderthal genome.

It is the first genetic blueprint of an extinct human species and a tour de force in terms of the scientific techniques used to recover tiny strands of ancient DNA from fragments of fossilised bones tens of thousands of years old.

Although scientists are far from answering the many questions about the last of our relatives known to live alongside anatomically modern humans, they believe the research is close to finding out what it is, genetically, that made us human.

Professor Svante Paabo, of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, will reveal at the American Association for the Advancement of Science in Chicago this weekend that he and his colleagues have deciphered 60 per cent of the Neanderthal genome and used it to calculate that the last common, apelike ancestor of modern man and the Neanderthals lived about 830,000 years ago.
The project took more than 21/2 years of research on dozens of Neanderthal bones between 40,000 and 70,000 years old excavated from four archaeological sites in Europe, stretching from southern Russia and Croatia, to Germany and Spain.

They extracted enough DNA from an analysis of 70 fossilised bones to build up a library of Neanderthal DNA covering 3.7 billion "base pairs" - the individual letters of the genetic code - and in the process discovered that the extinct humans were very closely related to modern people.

"The Neanderthals are so closely related to us that they fall into our [genetic] variation," Paabo said yesterday.

In other words, it would be difficult to distinguish Neanderthal DNA from the DNA of a modern European, Asian or African. The last Neanderthals died out about 30,000 years after sharing the same European landscape with modern humans for many thousands of years. It has been an enduring mystery why they disappeared and whether they ever interbred with their close human cousins - although the latest evidence from the DNA suggests they did not.

"What we have looked at from the point of view of variation today is the contribution from Neanderthals into the human gene pool. That was very little, if anything. Our data shows that, if there was a contribution, it was very small," Paabo said.

"But the cool thing is that interbreeding was a two-way street. For the first time we can look at whether there was a contribution from human ancestors into Neanderthals because, for the first time, we have a Neanderthal genome.

"We can analyse the Neanderthal genome and look at the contribution from human ancestors into them and that question remains totally open, and the analysis is ongoing."

Another question is whether Neanderthals could speak. Although they are known to have a hyoid bone in the throat, which is anatomically important for articulating words, the only other evidence comes from an analysis of a gene called FOXP2 known to be critical for speech development in modern humans.

Paabo said the Neanderthal FOXP2 gene shared two changes to its DNA sequence that were also seen in modern humans, but not in chimpanzees. These two changes supported the view that Neanderthals might have been able to communicate verbally.