Posted on April 22, 2008

Race in a Genetic World

John Harvard’s Journal, Harvard Magazine, May 2008


Is race, then, purely a social construct? The fact that racial categories change from one society to another might suggest it is. But now, says [Donna] Fullwiley, assistant professor of anthropology and of African and African American studies, genetic methods, with their precision and implied accuracy, are being used in the same way that physical appearance has historically been used: “to build—to literally construct—certain ideas about why race matters.”

Genetic science has revolutionized biology and medicine, and even rewritten our understanding of human history. But the fact that human beings are 99.9 percent identical genetically, as Francis Collins and Craig Venter jointly announced at the White House on June 26, 2000, when the rough draft of the human genome was released, risks being lost, some scholars fear, in an emphasis on human genetic difference. Both in federally funded scientific research and in increasingly popular practice—such as ancestry testing, which often purports to prove or disprove membership in a particular race, group, or tribe—genetic testing has appeared to lend scientific credence to the idea that there is a biological basis for racial categories.

In fact, “There is no genetic basis for race,” says Fullwiley, who has studied the ethical, legal, and social implications of the human genome project with sociologist Troy Duster at UC, Berkeley. She sometimes quotes Richard Lewontin, now professor of biology and Agassiz professor of zoology emeritus, who said much the same thing in 1972, when he discovered that of all human genetic variation (which we now know to be just 0.1 percent of all genetic material), 85 percent occurs within geographically distinct groups, while 15 percent or less occurs between them. The issue today, Fullwiley says, is that many scientists are mining that 15 percent in search of human differences by continent.


Nor can genetic tests verify a person’s race or ethnicity. Genes that affect skin pigmentation or blood proteins involved in malarial resistance, the authors note, may not measure direct and unique ancestry (for example, a founder effect), but reflect instead an evolutionary response to “shared environmental exposures.” Furthermore, the tests are based on comparisons to databases of DNA from living populations, and are therefore vulnerable to “systematic bias” because of “incomplete geographic sampling” or the fact that “present-day patterns of residence are rarely identical to what existed in the past.” One testing company even uses an underlying model that “reinforces the archaic racial view that four discrete ‘parental’ populations (Africans, Europeans, East Asians, and Native Americans) existed in the past” even though “there is little evidence that four biologically discrete groups of humans ever existed. . . .”


Lost in the discussion about genes, [Fullwiley] fears, are “epigenetic” influences: factors that affect gene expression but are not part of one’s genetic code, such as prenatal nutrition (which may influence rates of heart disease late in life). Such biosocial factors—environmental, cultural, and economic—can sometimes be more influential than genes. Fullwiley questions, for example, if the prevalence of diabetes among Native Americans on reservations, or of asthma among U.S. Latinos, is only genetic. Her research in Senegal has reinforced that doubt. Scientists have long searched for a genetic difference that would explain why many Senegalese experience a relatively mild form of sickle cell disease. Fullwiley’s work suggests that many of them may instead be mitigating their symptoms with a widespread cultural practice: phytotherapy—the ingestion of roots from a plant that, preliminary studies suggest, triggers production of fetal hemoglobin, a blood-cell type that doesn’t sickle. “When environmental history, or evolutionary history, gets reduced to racial or ethnic difference,” she says, “that’s a big mistake.”

Not all genetics projects are so potentially divisive, however. In February, Spencer Wells, Ph.D. ‘94, a former Lewontin student, came to Harvard to tell a story of human connectedness. Wells, who heads the joint National Geographic Society-IBM nonprofit Genographic Project, spent an afternoon with student members of the Harvard Foundation, which represents 72 student organizations “from the Albanian Society to the Vietnamese Society,” says director S. Allen Counter. Wells had previously invited the students to participate in the Genographic Project by sending in cheek swabs with their DNA for analysis. “The idea,” says Counter, “was to show a diverse group of students how they connect to the rest of humanity.”

Wells has created a human family tree that traces “the journey of man” (as he titled his 2002 book) in populating the entire planet from a homeland in Africa. The project has used linguistic and genetic studies to guide its sampling of indigenous populations from around the globe—many of them isolated and remote—and now has the world’s largest and most representative anthropological database of human DNA.

At Harvard, a Pakistani-American student whose family had always told her they were originally from an area near the Arabian Sea had this confirmed by her DNA result. “Your family was part of the first migration out of Africa,” noted Wells. “You share that with the Australian aborigines.” An African-American student with ancestors from East Africa carried a genetic signature characteristic of that region. But an Asian-American student was surprised to find that she carried almost the same genetic markers as a Mexican-American student. Wells explained, “There is only one change, but you are fairly different because your lines diverged a long time ago. Still, you are part of the same branch of the tree”: the Native Americans who populated the Western Hemisphere originally came from Asia.

Fullwiley’s own ethnographic research among genetic scientists suggests that much of current medical genetics may reinforce ideas of racial difference. Because certain diseases occur at higher frequencies in some populations (sickle cell anemia in blacks, Tay-Sachs disease in Jews of eastern European ancestry), they have become linked to the idea of race, even when the disease does not result from common ancestry. Sickle cell trait, for example, has arisen independently in several populations as an evolutionary response to malaria. The genetic change appeared first in India and then in Africa; it is also found in Greeks and Italians. But in the United States, Fullwiley says, sickle cell trait is very much linked to African-American racial identity through the history of medicine.

She says the potential for racialization of medical genetics has been institutionalized because “you can’t get a grant from the NIH unless you recruit in racial groups, label people by census category, and then report back the data in terms of outcomes by racial type.” The original intent—to counter the widespread use of the white male body as the working research norm—is “fine and good,” she says, but there “ought to be some flexibility to these race categories, and some thinking about what they mean. This new construction of race . . . is socially inflected—but it is not solely a social construct because biology is front and center.”