DNA tests help genealogists only so far

As the number of people looking for connections has grown, so has the number of critics of DNA testing. The technology does not come without caveats.

Harvard African American Studies professor Henry Louis Gates Jr. helped popularize DNA testing with a 2006 PBS special “African American Lives,” but after repeated tests with different companies, Mr. Gates said last year he had been given conflicting results. One company told him his maternal ancestors were Egyptian; another told him they were European.

Edward Ball, author of the book “The Genetic Strand,” writes that he had some ancestral hair samples tested. One company told him they were American Indian. Another company told him he had African genes but not American Indian genes. Still another told him his people came from Northern Europe.

Mr. Duster of NYU calls the business of genetic DNA testing “an unregulated no-man’s land.” He says he would like to see guidelines and transparency as the business evolves.

“Any company can claim that their laboratories can analyze your DNA to provide accurate information about your ancestry,” Mr. Duster says. “But if three different companies provide three different answers [as a report on CBS’ “60 Minutes” did in 2007], what is a consumer to do? Which company is correct? There is no way of knowing, since we have no ‘gold standard’ for excellence or professional self-policing.”

The American Society of Human Genetics (ASHG) has similar concerns. The group says that those who undergo ancestry testing often do not realize the tests are probabilistic and can reach incorrect conclusions, causing emotional distress if test results are unexpected or undesired.

The ASHG says consumers frequently purchase these tests to learn about their race or ethnicity, yet there is no clear-cut connection between an individual’s DNA and racial affiliation.

ASHG President Aravinda Chakravarti, from Johns Hopkins University School of Medicine, says the group recommends greater efforts on the part of both industry and academia to make the limitations of ancestry-testing estimation more clear. Consumers, meanwhile, have a responsibility to avail themselves of information about ancestry testing and to strive to better understand the implications and limitations of these tests.

The society also called for additional research to understand testing’s accuracy and for guidelines to be developed for ethical use of testing and research.