"For Cave Women, Farmers Had Extra Sex Appeal"

MADELEINE BRAND, host:

Ladies, you know how men seem to be in love with their gadgets? Does all their gear make them more or less attractive? Science suggests that the answer is more.

And guys, before you run out and upgrade your smart phones, take note of this: The technology in this next story refers to stone axes and other basic tools of agriculture. And the smitten women are the hunter-gatherers of prehistoric Europe.

NPR's Richard Harris explains.

RICHARD HARRIS: In these days of electronic gizmos and biotech, we don't necessarily think of farming and animal herding as cutting-edge technologies. But when people in the Near East developed them about 10,000 years ago, it changed everything.

Professor MARK JOBLING (Department of Genetics, University of Leicester): You can regard it as the most important cultural change in the history of modern humans.

HARRIS: Mark Jobling is at the University of Leicester in England.

Prof. JOBLING: It allowed people to generate their own food and populations to grow and society to become specialized and so on.

HARRIS: It was the foundation of modern civilization, so there's more than a little interest in understanding just how agriculture spread from where it originated, which was in present-day Turkey and Iraq.

Over about 4,000 years, these transforming technologies moved west, throughout all of Europe. The question is whether just the ideas swept the continent or whether the farmers themselves did.

Prof. JOBLING: We certainly know that the technology moved, so the evidence for whether the people moved or not has come a lot from genetic research in modern populations.

HARRIS: And that brings us to the story of the guys with their agricultural know-how. To track their movements, Jobling and his colleagues have been tracing the genetics of the Y chromosome, which is passed only from father to son. And in his new study in the journal PLoS Biology, he concludes that farming men did, indeed, move from the Fertile Crescent in the Near East all across Europe.

But here's the strange part. He did not see that pattern of westward movement of women when he looked at genes handed down exclusively from mothers.

Prof. JOBLING: And some people think, well, one of them must be wrong. They've got to be the same. But our view really is, well, why should they be, because they reflect the different sexes. And we know that men and women have behaved differently today and in the past.

HARRIS: In this case, Jobling sees a couple of possible explanations. He says maybe only farming men went west to seek their fortunes and left the farming women behind. As they moved west, the men made families with the hunter-gatherer women. Another possibility:

Prof. JOBLING: More likely that as the populations expanded from the Near East, they contained men and women. But then the indigenous people, the hunter-gatherers who were already in Europe, the women were incorporated into these societies and had offspring.

HARRIS: Men can have more kids than women, presuming they aren't monogamous, so their genes would spread much faster than the genes of any women who were traveling with them. And it seems the women in Europe welcomed the farmers with open arms.

In fact, the finding implies that the hunter-gatherer men of Europe were the real losers here. They couldn't compete with the Johnny-come-latelies who knew how to grow grain and tend animals, so their genes faded from the population.

The result is the genetic pattern we see in many Europeans today: male genes from farmers who hailed from the Near East and female genes mostly from women who had been hunter-gatherers in Europe after the last Ice Age.

So, to the punch line: Does technology make men more sexy?

Dr. PETER UNDERHILL (Department of Genetics, Stanford University): That would be one way to interpret it.

HARRIS: That's Peter Underhill at Stanford University. And he says sex appeal isn't the only possible reason.

Dr. UNDERHILL: Might be in terms of not just physical appearance but in terms of ability to provide for offspring.

HARRIS: So the farmer's daughters and sons would have more to eat and therefore would be more likely to survive and spread their genes to future generations. Underhill says the British study makes a pretty strong case for that.

Michael Hammer from the University of Arizona has found the same sort of story in how agriculture spread both in Africa and Japan.

Dr. MICHAEL HAMMER (Biotechnology Research Scientist, University of Arizona): Again, the Y chromosome shows a very clear pattern that looks like it's reflecting the spread of agriculture into Japan, starting about 2,100, 2,300 years ago.

HARRIS: And once again, it appears that men moved in on a population of women and outcompeted the men who where there already. So, assuming these scientists are reading the genes right, technology really can make a guy more attractive.

Richard Harris, NPR News.

(Soundbite of song, "She Thinks My Tractor's Sexy")

Mr. KENNY CHESNEY (Singer): (Singing) She thinks my tractor's sexy. It really turns her on. She's almost never left me while I'm chugging along.

ROBERT SIEGEL, host:

This is ALL THINGS CONSIDERED from NPR News.