The Reality of Race
SALLY LEHRMAN
Scientific American, 02 /2003
Race doesn't exist, the mantra went. The DNA inside people with different complexions and hair textures is 99.9 percent alike, so the notion of race had no meaning in science. At a National Human Genome Research Institute (NHGRI) meeting five years ago, geneticists were all nodding in agreement. Then sociologist Troy Duster pulled a forensics paper out of his briefcase. It claimed that criminologists could find out whether a suspect was Caucasian, Afro-Caribbean or Asian Indian merely by analyzing three sections of DNA.
"It was chilling," recalls Francis S. Collins, director of the institute. He had not been aware of DNA sequences that could identify race, and it shocked him that the information can be used to investigate crimes. "It stopped the conversation in its tracks."
In large part thanks to Duster, Collins and other geneticists have begun grappling with forensic, epidemiological and pharmacogenomic data that raise the question of race at the DNA level. The NHGRI now routinely includes experts from the social disciplines to assist in guiding research priorities and framing the results for the public. "The complexities of the DNA sequence require not just simplistic statements about similarities between groups but a full appreciation of history, anthropology, social science and politics," Collins has realized. "Duster is a person that rather regularly gets tapped on the shoulder and asked for help."
The urbane 66-year-old Duster, who splits his time between appointments at the University of California at Berkeley and New York University, examines how the public absorbs news about genetics into existing beliefs and how those perceptions also shape the use of genetic sequencing, DNA probes and other molecular techniques.
Those techniques have revealed that race is minor at the DNA level. The genetic differences between any two randomly selected individuals in one socially recognized population account for 85 percent of the variation one might find between people of separate populations. Put another way, the genetic difference between two individuals of the same race can be greater than those between individuals of different races--table sugar may look like salt, but it has more similarities with corn syrup.
DNA PROFILES raise issues about race that sociologists such as Troy Duster must ponder.
But genetics cannot prove that race doesn't exist, Duster explains. No amount of logic will erase the concept or destroy the disparities that arise from it, because people use race to sort their social groupings and to define their social and economic interactions. Moreover, they do so in ways that have significant biological consequences. Duster recently helped to draft a 15-page statement for the American Sociological Association showing how race persists as a factor in disparities in health and other areas of life. "You cannot just get rid of the concept without doing tremendous damage to the epidemiologic research done so far," Duster says. African-Americans are three times as likely to die from heart disease, for example. "Blacks are redlined by banks, followed by department store security, pulled over by the police. This can produce hypertension," he points out. "It can give you a heart attack."
A new approach, gene clustering, avoids race by dividing according to medically important markers, such as genes for the enzymes necessary to metabolize drugs. But society will very likely re-create racial categories and rankings under the new terms, Duster predicts. And by failing to name the social context, this strategy gives base-pair differences undue emphasis at the expense of environmental influences. Race is a social reality, Duster observes, and he warns that science itself is a social institution susceptible to essentialist perceptions of race.
Raised in poverty during the Great Depression by a mother from an upper-class family, Duster, whose father died when he was nine, grew up navigating between Chicago's tough streets and its privileged intellectual and civic parlors. He witnessed firsthand the complexities of social categories and learned to "code-switch" from one to another, much as he capably moves among sociology, anthropology and genetics now.
Duster started out as a journalist but quit in moral indignation when chided for failing to interview a trapped subway motorman waiting for a leg amputation. He turned to sociology and joined Berkeley in 1967, quickly developing a reputation for thought-provoking work on drugs and social policy. In the 1970s Duster was a familiar voice in National Institutes of Health committees reviewing grants for research on mental health and drug abuse. While sitting on a panel for President Jimmy Carter's Commission on Mental Health, he began to hear researchers speculate that drug addiction and mental illness were linked to genetic susceptibilities.
Duster found the conversations alarming. His book, Backdoor to Eugenics, aimed to stimulate public debate by showing how genetic-screening policies tended to reinforce the power structures already within society. Since then, he has pressed geneticists and molecular biologists to consider the social meaning that emerges from what they perceive as unbiased fact.
At first they resisted. As a member of the Ethical, Legal and Social Implications Working Group advising the agencies on human genome research, Duster urged the NIH and the Department of Energy to challenge The Bell Curve, the 1994 best-seller that argued that race correlated with intelligence. Government officials held up a response for eight months, convinced that the nonexistence of race at the genome level spoke for itself.
Duster, along with fellow committee member Dorothy Nelkin of New York University, highlighted the ways in which cultural context influences the application of medical and behavioral genetics. Now Collins is relying on Duster and other collaborators, such as University of Wisconsin molecular biologist Pilar Ossorio, to help explain why race must be acknowledged even if it is biologically inconsequential. "It's a tightrope between trying to rescue the importance and meaning of research on race without giving it a false reality," Duster says.
Indeed, although he maintains that race is significant in genetics, Duster insists it is misleading to reinscribe race as a definitive system to group people who share geographic origins and thus some genes. For one, concepts of race vary geographically as well as historically. The ethnic status of South Asians, for example, has changed over the past century in the U.S. and more often serves to define a political and cultural "other" than something biological. In 1920 Oregon granted citizenship to Bhagat Singh Thind of India during a ban on Asian immigration. But the U.S. Supreme Court disagreed, stating that even though Thind should be considered "Caucasian," he still wasn't "white." (Thind, who had joined the U.S. Army during World War I, managed to stay in the country, earn a Ph.D. and publish 15 books on metaphysics.)
Researchers have also advocated assessing health risks within ethnic groups based on inherited variations in just one DNA base pair. But such single-nucleotide polymorphism (SNP) profiles can be deceptive, Duster warns. Ethnic differences in drug metabolism or response to tobacco exist, but they appear to be minimal and depend strongly on the environment. The emphasis on DNA, he remarks, transforms health status into a biological inevitability, and it is tempting to use the same tools to profile criminality or intelligence at the genome level.
Specific variations in DNA can be linked to ancestral geographic origins, but those differences only occasionally offer a medically important clue. They fail to define any essential characteristics of a whole group. Race, itself a fluid idea, is part of the environmental context of the genome, Duster suggests. "Race is a relationship," he says. "When you talk about race as a relationship, it prevents anyone from giving it false meaning."