Sleep with Neanderthals? Apparently we (homo Sapiens) did

Though it's been 150 years since mysteriously humanlike bones first turned up in Germany's Neander Valley, the find continues to shake our collective sense of human identity.

Neanderthals are humanity's closest relatives, with brains at least as big as ours, and yet we don't know whether we should include them as members of our own species.

No longer does science consider them our direct ancestors but some suspect Neanderthals and modern homo Sapiens interbred during the 20,000 some-odd years we co-existed in Europe. The archaeological record doesn't tell us one way or another, but earlier, researchers announced they would seek more clues by scraping DNA from Neanderthal bones and teeth.

The question of sex with Neanderthals speaks to our understanding of ourselves, our origins and our uniqueness. If this other type of human being wasn't like us, what was he like?

As I started researching this issue, I found myself staring at a picture of a nude Neanderthal man — a forensic sculpture created by Duke University paleoanthropologist Steve Churchill that was published last year in the journal Science. The model, based on a skeleton found at La Ferrassie in France, is mesmerizing in its combination of familiarity and alienness.

To be honest, he's really not half bad looking. He's got a good, muscular body, and while he's nobody's idea of handsome, that could be forgiven if he had a nice personality or I was starving and he offered to throw some rhino steaks on the fire for me.

We're not talking about the stoop-shouldered, hairy, apelike Neanderthal of popular culture. There's no evidence they were hairier than modern people, says anthropologist Harold Dibble, a curator at the University of Pennsylvania Museum of Archaeology and Anthropology. For all we know our La Ferrassie man had a smooth chest and back.

Nor is there any reason to consider Neanderthals more closely related to chimpanzees than we are. The current scientific consensus holds that our ancestors and those of Neanderthals branched off from a common "archaic human" ancestor about 800,000 years ago.

Around half a million years ago the Neanderthal line spread through Europe and the Middle East, while our dominant ancestral line didn't move into Europe until much later — around 45,000 years ago. There, we overlapped until about 28,000 years ago.

The archaeological record suggests Neanderthals knew how to control fire and created complex tools. "No matter how you cut it, they were not the stone-age idiots they were portrayed as in bad movies," says John Relethford, an anthropologist at State University of New York at Oneonta and author of "Genetics and the Search for Modern Human Origins."

We don't know why Neanderthals went extinct, he says. It could have been genocide, disease, a change in available food sources or absorption into our gene pool through sex. It didn't have to be anything dramatic, he says. When two groups are living in the same environment, it takes only a slight edge for one group to dominate.

Will genetics fill in the story's gaps? That's the hope, says Michael Egholm of the Connecticut-based 454 Life Sciences. Getting good information from Neanderthal bones is a long shot considering the majority of DNA they extract comes from bacteria and contamination from people.

But clues also lay within the DNA we're carrying around in our cells today. Biologist Alan Templeton of Washington University in St. Louis has found hints that some people of European ancestry carry genes that emerged in Europe more than 300,000 years ago — far before our main ancestors left Africa.

The story Templeton's genetic studies tell is one of successive waves of humanlike groups moving from Africa to Europe and Asia, first more than a million years ago, again 800,000 years ago and again less than 100,000 years ago. Each wave of immigrants appears to have mixed with the previous one already living in Eurasia.

It certainly mirrors what we know of the more recent history of human migration and exploration. Even when unfamiliar groups label each other as subhuman, they almost always have sex anyway.

Faye Flam's Carnal Knowledge column appears Sundays in The Seattle Times.