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By Nicholas Wade, NY Times
A company in Sarasota, Fla., is offering a DNA test that it says will measure customers' racial ancestry and their ancestral proportions if they are of mixed race.
Claiming to be "the world's first recreational genomics testing service," the company, DNAPrint Genomics Inc., says its test will be useful for people interested in their own origins as well as for more practical purposes, like "to validate your eligibility for race-based college admissions or government entitlements."
A test costs $290, or $160 for an initial period, and is conducted on DNA from cells swabbed from the inside of a customer's cheek.
Dr. Tony Frudakis, a molecular biologist who is the company's chief executive, said the test would help "belie the myths on which racism is based" by showing that "in all of us, especially in the U.S., there is a continuum of ancestries."
But geneticists independent of the company expressed reservations about the accuracy of any such test, noting that there was still relatively little data about genetic differences between ethnic groups.
"It's possible in principle to estimate the extent of admixture, but the number is not going to be very accurate," said Dr. Stephen J. O'Brien, a population geneticist at the National Cancer Institute, referring to the proportion of different ancestry in people of mixed race.
Dr. Frudakis said the test was based on a set of genetic markers known as SNP's, pronounced "snips," that were mostly drawn from public databases. SNP's are sites along the human genome where alternative chemical letters of DNA, the genetic material, are commonly found, with some people having one letter, some another.
Working with Dr. Mark Shriver of Pennsylvania State University, DNAPrint Genomics has developed SNP's that are diagnostic of a person's continent of origin, Dr. Frudakis said. These five geographical areas correspond to the major human population groups or races, those of "Native American, East Asian, South Asian, European, sub-Saharan African, etc.," according to the company's Web site.
The SNP's were validated by testing them against a panel of people from the five continental areas, and the accuracy of the overall test has been checked by comparing results with known pedigrees, Dr. Frudakis said.
All human populations have the same set of genes and much the same set of variant forms of these genes, inherited from the predecessor species. But small differences, mostly a shift in the frequency of common genetic variations, have built up over time in different populations around the world. Study of these differences has come to the fore largely as a byproduct of two other lines of inquiry made possible by the Human Genome Project. One is the ability to track ancient migrations out of Africa from the different pattern of DNA changes that have accumulated among populations in each continent breeding in substantial isolation from one another.
The other line of inquiry, into the identity of variant genes that cause disease, has run into the fact that different ethnic groups appear to have somewhat different patterns of genetic causation, leading biomedical scientists to debate whether race should be taken into account in studies of disease. But most researchers are still reluctant to study race as such, and the DNAPrint test seems to go further than anything in the published scientific literature.
Dr. David B. Goldstein, a population geneticist at University College London, said that it was misleading to suppose that the human population fell into five neat groups, as the DNAPrint researchers implied, and that the true pattern would probably turn out to be much more complicated. "This test really jumps the gun in reifying groups that don't have scientific support," he said.
But the test could in principle provide valid information in assessing the relative degree of a person's heritage from two known populations, like West Africans and Europeans, Dr. Goldstein said.
He and Dr. O'Brien expressed concern that tests like DNAPrint's might do more harm than good. If the promise of the Human Genome Project is fulfilled and genetic information starts to flow into the clinic, "People will need a high level of confidence in what geneticists tell them, so this kind of casual stuff is quite dangerous if it makes people skeptical of genetic information," Dr. Goldstein said.
But Dr. Shriver sees use of the test as beneficial. "The ultimate outcome is that we are breaking down a dichotomous classification," he said, meaning that instead of people being considered either black or white, his test would show a continuous spectrum of ancestry among African-Americans and others.
The spectrum of mixed ancestry continues into the European-American population, about 10 percent of whom have some African ancestry, Dr. Shriver said. He had discovered to his surprise that that included him. Probably through a Mexican grandmother, he carries the Duffy null allele, he said, a gene variant that protects against malaria and is very common in sub-Saharan Africans but rare among others.
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