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February 09, 2005

Race is obsolete...?

No one has pointed this out yet, so I thought I would highlight a few research articles that have been published recently in the battle over race in biomedical research.

Now we have the APA (American Psychological Association) declaring that race is obsolete.

New and sophisticated methods for studying the relationship between human genetic differences, the environment, health and behavior, all made possible by the completion of the Human Genome Project, have made traditional race-based measurements of human differences obsolete, according to numerous authors writing in a special issue of the American Psychologist devoted to Genes, Race, and Psychology in the Genome Era (January, 2005).

Full text of the issue available here.

To which I would respond, then explain this:

Racial groupings match genetic profiles, Stanford study finds

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. . . .

The people in this research were all part of a study on the genetics of hypertension, recruited at 15 locations within the United States and in Taiwan. This broad distribution is important because it means that the results are representative of racial/ethnic groups throughout the United States rather than a small region that might not reflect the population nationwide.

For each person in the study, the researchers examined 326 DNA regions that tend to vary between people. These regions are not necessarily within genes, but are simply genetic signposts on chromosomes that come in a variety of different forms at the same location.

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 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.

And this:

Hypertension in African Americans linked to two genomic regions

A first-of-its-kind application of a novel statistical method of analysis to African Americans has identified regions on chromosomes 6 and 21 that likely harbor genes contributing to high blood pressure in that group. The novel statistical method, called admixture mapping, narrowed the search for genes related to hypertension, bringing researchers and doctors closer to finding more effective treatments. . . .

In the U.S., 65 million people have high blood pressure, but it is found more often in African Americans than other groups. African Americans suffer from earlier and more severe hypertension and have a higher rate of death from stroke, heart disease, and kidney failure as a result.

The causes of hypertension are complex. Diet, exercise and stress contribute, but so do genetic factors. . . .

In a fresh approach to the problem, the researchers applied a genome-wide scan that compared how often genetic variations occur in people of African or European descent to how often they occur in African Americans.

As a group, African Americans can trace their ancestry largely to populations from both Africa and Europe. "The statistical technique we used is ideal for groups who have a trait with a higher occurrence--such as hypertension in African Americans--and who stem from two sets of ancestral populations that have differing genetic variations," Rao says.


"The admixture mapping method has distinct advantages over other more commonly used methods for population analysis," says C. Charles Gu, Ph.D., assistant professor of biostatistics and a co-author of the report. "We looked for genomic regions with an 'excess of ancestry' from one of the two populations. In this case we looked for excess ancestry from the African population, because it has a higher frequency of genes contributing to high blood pressure." Excess of ancestry is a term indicating the genomic region in African Americans is derived more often from one ancestral population than the other.

The researchers looked at the distribution of 269 genetic markers across the genome in each of the three groups. Compared to African Americans without high blood pressure, African Americans with high blood pressure were more likely to have a distribution of markers--in the identified genomic regions--resembling that of the African (ancestral) group.

The excess African ancestry among people with high blood pressure enabled the researchers to find two locations, one on chromosome 6 and one on chromosome 21, that stood out with the strongest association to high blood pressure in African Americans. Other markers close by on the same chromosomes also had a strong association with high blood pressure, indicating that the chromosome regions near these two groups of markers probably contain genes responsible for an increased risk of hypertension.

Researchers can now use this information to help locate genes affecting hypertension. "When a specific gene variant associated with hypertension is identified, physicians will be able to test patients for their risk of hypertension to head it off early," Rao says. "In addition, research institutions and pharmaceutical companies can develop new drugs that compensate for the effect of that gene."

References:

Tang H, Quertermous T, Rodriguez B, Kardia SL, Zhu X, Brown A, Pankow JS, Province MA, Hunt SC, Boerwinkle E, Schork NJ, Risch NJ. Genetic structure, self-identified race/ethnicity, and confounding in case-control association studies. Am J Hum Genet. 2005 Feb;76(2):268-75. Epub 2004 Dec 29. PMID: 15625622

Zhu X, Luke A, Cooper RS, Quertermous T, Hanis C, Mosley T, Gu CC, Tang H, Rao DC, Risch N, Weder A. Admixture mapping for hypertension loci with genome-scan markers. Nat Genet. 2005 Feb;37(2):177-81. Epub 2005 Jan 23. PMID: 15665825

Addendum from Razib: PDF of the Risch paper in question.

Posted by rikurzhen at 05:10 PM