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Thursday, Feb. 12, 2004
To run, or not to run, the race issue
By ROWAN HOOPER
Last year, when Californians had to choose between Hollywood star Arnold Schwarzenegger and incumbent Democrat Gray Davis to be their governor, they also had to vote on another divisive issue: Proposition 54. This law, the so-called Racial Privacy Initiative, sought to ban the state collection of information on race, ethnicity, color or national origin.
It was a law, said its supporters, that would make California colorblind. It was championed by businessman Ward Connerly, who was also the primary force behind Proposition 209, which banned affirmative-action programs in the state in 1996.
"The only way we're going to solve the dilemma of race," said Connerly, "is to start seeing ourselves as basically one human family, not divided by color or by where our granddaddy came from."
Admirable sentiments, and ones supported by some recent genetic studies. Reviewing them in a paper in Science in 2001, Svante Paabo of the Max Planck Institute of Evolutionary Anthropology, Leipzig, Germany, concluded that the gene pool in Africa is more diverse than elsewhere, and the genetic variation found outside Africa is only a subset of that found in Africa.
Such variation, said Paabo, means that we're all essentially African even if we don't live there, and that divisions of race are biologically meaningless.
But other studies, including one in the journal Nature Reviews Cancer -- published last month -- suggest that human populations can be divided into groups consistent with race, and that furthermore, genetic markers linked to ethnicity may predict cancer risk. So what do we do? Retain the old categories based on skin color or strive for a "colorblind" society?
The Nature Reviews Cancer paper, by epidemiologist John Wiencke of the University of California, San Francisco, may help us to solve this problem. It comes at a time when there is growing concern about the collection of racial data, about genetic privacy and about the use of the information in the human genome in general.
When it was announced in 2001 that the human genome had been sequenced, British Prime Minister Tony Blair called it "the first great technological triumph of the 21st century." That is true, but with the genome's completion came another first, the first great philosophical/moral problem of this century. How much should the state know about the genetic makeup of its citizens, and what -- if anything -- should we do with that information?
The huge genetic variation within races notwithstanding, it turns out that many diseases are more likely to occur in certain ethnic groups. For example, sickle cell anemia disproportionately affects African-Americans; Hispanics are twice as likely to have diabetes as whites of similar age; and adult-onset diabetes strikes Native Americans three times as often as whites. How much of this is due to environmental factors and how much is genetic? Only more research can tell us.
"Attention to racial differences might help in identifying new cancer-causing agents," writes Wiencke. "If a specific cancer is prevalent in among one racial/ethnic group, investigations into the lifestyle and environment of that group could uncover a previously unrecognized carcinogen."
It is cancer that Wiencke is interested in. For example, he found that Texan Hispanics have a higher incidence of gastric cancer, and Ashkenazi Jews and African-Americans have a higher incidence of breast cancer than the rest of the population. The average annual incidence of prostate cancer in the United States is 277 per 100,000 for African-Americans and 168 per 100,000 for Caucasians. Lung-cancer risks and mortality rates are higher for African-American men than any other group, but the death rates from other cancers in different ethnic groups seem to vary according to each study.
Primary brain tumors were higher in Caucasians than in nonwhites. Gliomas (a particularly nasty kind of brain tumor) in Caucasians are usually caused by a mutation in a gene called CDKN2A, but this mutation is less common in Japanese glioma patients -- something else accounts for the tumor in these cases.
"Although scientists debate the value of racial information," said Wiencke, "it is likely to be counterproductive to continue to ignore race while searching for the molecular underpinnings of human cancer."
What does this mean? For one, that our health professionals, at least, shouldn't be colorblind. For another, that we recognize how genetic divergence has come about.
Humans migrated out of Africa between 60,000 and 40,000 years ago. They settled in Asia, Oceania, Europe and America, in that order. Different groups experienced different environments and natural selection worked on them in different ways.
So natural selection on our ancestors led to genetic changes, and Wiencke and many other scientists are finding that these changes can predispose us to different sort of diseases. And as it happened, the people of California agreed.
Sixty-four percent of Californians voted to reject Proposition 54. They knew that even though racial data could in theory be used for discrimination, not having such data would be a greater danger. California birth and death certificates would have no longer listed race, so researchers studying how different groups suffer from disease would have a much harder time.
In particular, Wiencke's job would be much harder. "Developments in evolutionary biology and genetics compel us to address the value of ethnic and racial categories to ensure that we do not pass up any opportunity to improve the prospects for cancer prevention," he said.
Rowan Hooper is a researcher at Trinity College Dublin. He welcomes comments at firstname.lastname@example.org