AUSTIN, Texas
The availability of genetic ancestry tests has generated considerable interest among Americans eager to learn about the racial background of their ancestors. Last month, a University of Texas assistant anthropology professor, in association with 13 researchers from across the United States, urged the scientific community to better inform the public about the shortcomings of the tests and called upon consumers to consider the tests with caution.

In recent years, DNA ancestry testing has found unique favor among African-Americans. Given the tragic dislocation of the transatlantic slave trade, many African-Americans have had difficulty tracing their ancestry through surname research and other archives. DNA testing has offered African-Americans what many believed is a compelling new tool to discover more information about their heritage. In the PBS documentary “African-American Lives,” show host Dr. Henry Louis Gates Jr. and the producers had the DNA of prominent African-Americans, such as Whoopi Goldberg, Oprah Winfrey and Quincy Jones, tested for the geographic origins of their ancestors.

Dr. Deborah Bolnick, an assistant professor of anthropology at the University of Texas at Austin, and fellow researchers urged caution with genetic ancestry tests in “The Science and Business of Genetic Ancestry Testing,” which appear in the Oct. 19 issue of Science. The article reports that at least two dozen firms offer genetic ancestry tests, which usually range from $100 to $900, to help consumers learn the racially and ethnically correlated origins of their ancestors. More than 460,000 people have purchased the tests during the past six years.

Test limitations reported by Bolnick and her co-authors include:

• No definitive link exists between DNA and racial/ethnic identity.

• Tests cannot show exactly where ancestors lived, or what ethnic identity they held.

• Most tests track few of a person’s ancestors and a tiny portion of his/her DNA.

• Tests are unlikely to identify all of the groups or locations around the world where a test-taker’s relatives are found.

• Limited sample databases mean test results are subject to misinterpretation.

The researchers contend that the assumptions and shortcomings of the tests make them less informative than many realize, and that commercialization has spawned misleading practices.

“Not all companies make clear the limitations and assumptions underlying these tests,” Bolnick says. “Because it is important for consumers to understand what the tests can and cannot tell them, we are encouraging professional genetic and anthropological associations to develop policy guidelines regarding genetic ancestry testing.”

To learn more about Bolnick’s research, visit www.sciencemag.org to see the Oct. 19 issue of Science.