Red hair a part of Neanderthal genetic profile

PHILADELPHIA — In an unprecedented feat of forensic anthropology, European researchers extracted enough DNA from two Neanderthal skulls to suggest their owners sported red hair and white skin when they were alive 43,000 and 50,000 years ago.

The hair color of humanity's closest relative might sound trivial, but the finding, announced today in the journal Science, stunned anthropologists with the sheer power of genetics to reveal what Neanderthals looked like and how they behaved. And that, some say, will change the way humanity views itself.

"We are building an image of these Neanderthal people — their physical aspects, cognitive abilities, metabolism, immunity — the range is enormous," said Carles Lalueza-Fox of Barcelona, an author of the paper.

The same team announced last week that Neanderthals and today's humans share a gene associated with language.

Until now, the understanding of Neanderthals was limited mostly to bone structure and artifacts. Scientists knew they used stone tools, were stockier than we are and had prominent brow ridges.

Only in recent years has genetics technology advanced enough to read the much-degraded DNA lodged in Neanderthal bone cells.

"My feeling is this will revolutionize the study of human origins," said Harold Dibble, a curator at the University of Pennsylvania Museum of Archaeology and Anthropology.

Scientists found the first Neanderthal fossils 150 years ago in Germany's Neander Valley. Since then, enough fossils surfaced to show their lineage branched off from ours about 500,000 years ago, in Africa.

Both human and Neanderthal lineages continued to evolve with bigger brains after parting ways. Neanderthals left behind stone tools, and they almost certainly used fire, but they went extinct about 17,000 years ago, after a considerable overlap with our own species.

Anthropologists generally consider Neanderthals to be human — a member of the human family that may have interbred with our ancestors.

But in the late 20th century the field split over just how similar Neanderthals were to us, Dibble said. He calls the two factions the "smart Neanderthal camp" and the "dumb Neanderthal camp."

The "dumb" camp says Neanderthals were significantly less intelligent than modern man despite a comparable brain size. They lacked language and complex social order and couldn't possibly have interbred with our ancestors.

The "smart" Neanderthal camp says they had intelligence comparable to ours, they talked and otherwise behaved like human beings.

To get past that impasse, a group of scientists led by Svante Paabo of the Max Planck Institute of Evolutionary Anthropology in Germany started attempting to sequence Neanderthal DNA — a venture many regarded as a longshot.

Lalueza-Fox said the team decided to focus on a skin-pigment gene, called MC1R, because it was related to one known difference between Neanderthal and modern human history: Neanderthals left for Europe and the Middle East some 400,000 years ago while our ancestors stayed in Africa until about 50,000 years ago.

In Africa, there's huge evolutionary pressure to retain a certain version of this gene that promotes dark pigment, he said. Anyone with a genetic mistake that interfered with that would be left vulnerable to sunburn and skin cancer.

But in Europe, variations of this pigment gene can thrive and even flourish, since light-skinned people more efficiently produce vitamin D in relatively northern regions. One variant, for example, is common among Irish people and leads to red hair and pale, freckled skin.

Lalueza-Fox and colleagues found a different variant of the same gene in their Neanderthal samples.

But how do they know this new variant led to red-haired, white-skinned Neanderthals? Both the Neanderthal and modern versions hold the recipe for a similarly disabled version of a protein, said Hopi Hoekstra, an evolutionary geneticist at Harvard University.

"It's like a proof of concept," Dibble said. The finding bolsters the case that scientists can sequence DNA from Neanderthal bones and shed light on dozens of other traits.