The Genetics of Race

Not to pick at old wounds, but I remember distinctly at a New Republic editorial meeting over a decade ago that the idea that there was a biological component to race was described as an absurd and wicked anachronism. We all knew now that race was entirely a pernicious social construction that had no meaning whatsoever in biology or science. Moreover the notion that there might be subtle, genetic bell-curve differences in intelligence between what we identify as races was itself a form of neo-Nazi propaganda, as despicable as it was unfounded. Read this piece in the Science Times today and see whether you think this orthodoxy does not warrant some skepticism. Of course, race is a terribly problematic term. As miscegenation increases and we head toward a more multi-colored world, such concepts will hopefully become meaningless. But not yet. Race makes biological sense in broad categories:

A genomic survey of world populations by Dr. Feldman, Noah Rosenberg and colleagues in 2002 showed that people clustered genetically on the basis of small differences in DNA into five groups that correspond to the five continent-based populations: Africans, Australian aborigines, East Asians, American Indians and Caucasians, a group that includes Europeans, Middle Easterners and people of the Indian subcontinent. The clusterings reflect "serial founder effects," Dr. Feldman said, meaning that as people migrated around the world, each new population carried away just part of the genetic variation in the one it was derived from. The new scans for selection show so far that the populations on each continent have evolved independently in some ways as they responded to local climates, diseases and, perhaps, behavioral situations.

The concept of race as having a biological basis is controversial, and most geneticists are reluctant to describe it that way. But some say the genetic clustering into continent-based groups does correspond roughly to the popular conception of racial groups.

The differences are subtle, and bell curves apply. There’s massive overlap between different populations. Focusing on the minor differences while ignoring the huge similarities is a strange emphasis. But that such subtle differences exist, and that we will soon be able to measure them rather clearly, is something we’re just going to have to deal with at some point. From skin color (which seems to have become pale for Caucasians as recently as 7,000 years ago) to lactose tolerance to variants in disease and even hearing, the genetics of race are clear. And yes why would they not also affect cognitive functioning as well? Money quote:

Another puzzle is presented by selected genes involved in brain function, which occur in different populations and could presumably be responses to behavioral challenges encountered since people left the ancestral homeland in Africa.

But some genes have more than one role, and some of these brain-related genes could have been selected for other properties.

Two years ago, Bruce Lahn, a geneticist at the University of Chicago, reported finding signatures of selection in two brain-related genes of a type known as microcephalins, because when mutated, people are born with very small brains. Two of the microcephalins had come under selection in Europeans and one in Chinese, Dr. Lahn reported.

He suggested that the selected forms of the gene had helped improved cognitive capacity and that many other genes, yet to be identified, would turn out to have done the same in these and other populations.

Neither microcephalin gene turned up in Dr. Pritchard’s or Dr. Williamson’s list of selected genes, and other researchers have disputed Dr. Lahn’s claims. Dr. Pritchard found that two other microcephalin genes were under selection, one in Africans and the other in Europeans and East Asians.

Even more strikingly, Dr. Williamson’s group reported that a version of a gene called DAB1 had become universal in Chinese but not in other populations. DAB1 is involved in organizing the layers of cells in the cerebral cortex, the site of higher cognitive functions.

I don’t believe these scientists are racist.