DNA Proves Man Not Descended from Neanderthals

July 11, 1997 6:31 AM EDT

By Maggie Fox

LONDON (Reuter) - They looked a lot like us and acted a lot like us but Neanderthals were not our ancestors, ground-breaking genetic evidence published Friday indicates.

An international team of scientists said they had, for the first time, extracted DNA from the bones of a Neanderthal and proved he was too distant genetically to have been an ancestor of modern humans.

The finding will help tip the balance in the bitter dispute about how humans evolved.

``This is equivalent to landing the Pathfinder on Mars and getting it to work,'' said Chris Stringer, an expert in early humans at London's Natural History Museum. ``It's marvelous that someone has achieved it.''

Svante Paabo of the University of Munich and a team of experts from Germany and from Pennsylvania State University managed to extract and analyze the DNA from the bones of a Neanderthal more than 30,000 years old.

Using techniques that help scientists determine how closely living beings are related genetically, they determined that the ancestors of Neanderthals branched off the human family tree 600,000 years ago.

``It is extremely difficult to do, particularly since the techniques we use are so sensitive, so they tend to pick up (outside) DNA contamination,'' Paabo told a news conference in London. The findings are published in the journal Cell.

Paabo said his team ran four separate tests for authenticity -- checking to see whether other amino acids had survived, making sure the DNA sequences they found did not exist in modern humans, making sure the DNA could be replicated in their own lab and then getting other labs to duplicate their results.

``I have not encountered anyone in the scientific world who doubts that they have recovered Neanderthal DNA,'' Stringer said.

Paabo said the DNA came from the first skeleton of a Neanderthal ever found, in Germany's Neander Valley in 1856.

``The fossil we have worked with is not just any Neanderthal...it is the Neanderthal that has given the name to the species,'' he said.

``We know if anything is a Neanderthal, this is a Neanderthal,'' Stringer added. ``One couldn't have hoped for a better specimen.''

Comparisons with the DNA of modern humans and of apes showed the Neanderthal was about halfway between a modern human and a chimpanzee.

Stringer said the evidence firmly supported the so-called ``Out of Africa'' theory of human origins. He and others who subscribe to this theory say modern humans evolved in Africa and spread across the world about 100,000 years ago.

The other, competing theory is that Homo Erectus -- an early ancestor of humans -- moved out of Africa and across the world and that modern humans evolved separately but in parallel in several different regions.

Both theories were reached by examining fossils. ``Now we have a completely different approach,'' Stringer said. ``About 100,000 years ago our real ancestors emerged from Africa.''

Friday's announcement should help settle a ``heated'' and ``sometimes unpleasant'' debate, he said.

There is much evidence that Cro-Magnon people, who became modern humans, lived side-by-side with and interacted with Neanderthals, which died out about 30,000 years ago. Some ancient tools and jewelry indicate they may have traded.

But Stringer said the genetic evidence showed that was it. ``It does not look like they interbred with our ancestors,'' he said.

But, he stressed: ``They weren't ape-men...They were like us in many ways. They had big brains. They walked upright.''

Thomas Lindahl, a DNA expert for Britain's Imperial Cancer Research Fund, said it was remarkable the DNA had survived. It degraded very easily. ``It's a real tour de force and probably the most important work that has been done so far on ancient DNA,'' he said.

Paabo said perhaps the DNA had survived because the fossil came from the cold north of Germany. Efforts to get DNA from fossils from the Middle East had so far failed, he said.

He also said the bones had been shellacked, which could have preserved the DNA and protected them from contamination by modern DNA.