Race is good enough for government work: Geneticist Neil Risch, who recently moved from Stanford to UC San Francisco medical school, has done a DNA study of 3,636 people from 15 locations in the US and Taiwan.
Checking a box next to a racial/ethnic category gives several pieces of information about people - the continent where their ancestors were born, the possible color of their skin and perhaps something about their risk of different diseases. But a new study by researchers at the Stanford University School of Medicine finds that the checked box also says something about a person's genetic background.
This work comes on the heels of several contradictory studies about the genetic basis of race. Some found that race is a social construct with no genetic basis while others suggested that clear genetic differences exist between people of different races.
What makes the current study, published in the February issue of the American Journal of Human Genetics, more conclusive is its size. The study is by far the largest, consisting of 3,636 people who all identified themselves as either white, African-American, East Asian or Hispanic. Of these, only five individuals had DNA that matched an ethnic group different than the box they checked at the beginning of the study. That's an error rate of 0.14 percent....
Without knowing how the participants had identified themselves, Risch and his team ran the results through a computer program that grouped individuals according to patterns of the 326 [DNA] signposts. This analysis could have resulted in any number of different clusters, but only four clear groups turned up. And in each case the individuals within those clusters all fell within the same self-identified racial group.
"This shows that people's self-identified race/ethnicity is a nearly perfect indicator of their genetic background," Risch said.
When the team further analyzed each of the four clusters, they found two distinct sub-groups within the East Asian genetic cluster. These two groups correlated with people who identified themselves as Chinese and Japanese. None of the other genetic groups could be broken down into smaller sub-sections. This suggests that there isn't enough genetic difference to distinguish between people who have ancestry from northern Europe versus southern Europe, for example. Risch admitted that few people in this study were of recent mixed ancestry, who might not fall into such neat genetic categories.
I've often pointed out the absurdities inherent in the U.S. Government's race and ethnicity guidelines, but I've also admitted that on the whole they tend to be good enough for government work.
Risch has been working to show that self-identification into broad categories is good enough for medicine, too. I think it's important, though, that doctors keep a relativistic, nesting model of racial groups in mind. For example, although most white subgroups are fairly similar genetically, they should watch out for where they aren't.
Consider alcohol. While doctors who believe that one glass of red wine per day helps the heart shouldn't hesitate to recommend it to Italians and Jews, whose ancestors have been drinking wine for thousands of years, they should ask some questions before recommending alcohol to Swedes and Finns, who often have a hard time stopping once they start drinking. Likewise, the Japanese tend to get drunk fast but also don't have much trouble getting up and getting to work the next morning, but their distant cousins the American Indians have terrible problems with alcohol. Although Risch found that Hispanics lump together pretty well, I would guess that they'd be quite variable in relation to drinking, depending upon whether they inherited Iberian or Amerindian genes for processing alcohol.