March 14, 2005


A Family Tree in Every Gene (ARMAND MARIE LEROI, 3/14/05, NY Times)

The idea that human races are only social constructs has been the consensus for at least 30 years.

But now, perhaps, that is about to change. Last fall, the prestigious journal Nature Genetics devoted a large supplement to the question of whether human races exist and, if so, what they mean. The journal did this in part because various American health agencies are making race an important part of their policies to best protect the public - often over the protests of scientists. In the supplement, some two dozen geneticists offered their views. Beneath the jargon, cautious phrases and academic courtesies, one thing was clear: the consensus about social constructs was unraveling. Some even argued that, looked at the right way, genetic data show that races clearly do exist.

The dominance of the social construct theory can be traced to a 1972 article by Dr. Richard Lewontin, a Harvard geneticist, who wrote that most human genetic variation can be found within any given "race." If one looked at genes rather than faces, he claimed, the difference between an African and a European would be scarcely greater than the difference between any two Europeans. A few years later he wrote that the continued popularity of race as an idea was an "indication of the power of socioeconomically based ideology over the supposed objectivity of knowledge." Most scientists are thoughtful, liberal-minded and socially aware people. It was just what they wanted to hear.

Three decades later, it seems that Dr. Lewontin's facts were correct, and have been abundantly confirmed by ever better techniques of detecting genetic variety. His reasoning, however, was wrong. His error was an elementary one, but such was the appeal of his argument that it was only a couple of years ago that a Cambridge University statistician, A. W. F. Edwards, put his finger on it.

The error is easily illustrated. If one were asked to judge the ancestry of 100 New Yorkers, one could look at the color of their skin. That would do much to single out the Europeans, but little to distinguish the Senegalese from the Solomon Islanders. The same is true for any other feature of our bodies. The shapes of our eyes, noses and skulls; the color of our eyes and our hair; the heaviness, height and hairiness of our bodies are all, individually, poor guides to ancestry.

But this is not true when the features are taken together. Certain skin colors tend to go with certain kinds of eyes, noses, skulls and bodies. When we glance at a stranger's face we use those associations to infer what continent, or even what country, he or his ancestors came from - and we usually get it right. To put it more abstractly, human physical variation is correlated; and correlations contain information.

Genetic variants that aren't written on our faces, but that can be detected only in the genome, show similar correlations. It is these correlations that Dr. Lewontin seems to have ignored. In essence, he looked at one gene at a time and failed to see races. But if many - a few hundred - variable genes are considered simultaneously, then it is very easy to do so.

Denying the existence of race was the least Darwinists could do after the Nazis applied Darwinism with such horrific scientific dispassion and it's understandable that the effort to deny it was led by the Darwinist Left, like Mr. Lewontin and Stephen Jay Gould. But it's such obvious nonsense that it has only helped undermine the overall theory, demonstrating the degree to which adherents are prepared to accept utter incoherence for merely political/philosophical purposes.

Posted by Orrin Judd at March 14, 2005 11:48 AM

From the article:

"Most scientists are thoughtful, liberal-minded and socially aware people."

Why, they're practically perfect!

Posted by: Bruce Cleaver at March 14, 2005 12:21 PM

"demonstrating the degree to which adherents are prepared to accept utter incoherence for merely political/philosophical purposes"

Goodness - now why did you impose that arbitrary limit on 'Nature' the other day, saying that it had some kind of border, just to try to make some kind of point that went nowhere? Seems to me it falls under this very category.

Posted by: creeper at March 14, 2005 2:13 PM


There is are definitions of species and race that are generally used by biologists.

It's always hard to pin Orrin down to just one, though.

Anyhow, if you think you can identify people's ancestries just by looking at them, come to Hawaii and show me. Bet you can't.

Posted by: Harry Eagar at March 15, 2005 4:39 PM