Researchers Underscore Limitations of Genetic Ancestry Tests,
Urge Caution When Interpreting Results
October 18, 2007
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AUSTIN,
Texas—Although many people rely on commercially available genetic tests
for insights into their ancestry, the tests have significant
limitations, according to Deborah Bolnick, assistant professor of
anthropology at The University of Texas at Austin.
In "The
Science and Business of Genetic Ancestry Testing," which appears in the
Oct. 19 issue of Science, Bolnick and 13 researchers from universities
across the nation call upon the scientific community to better educate
the public about the limitations of the tests, and urge consumers to
approach the tests with caution.
At least two dozen companies market genetic ancestry tests, which
typically cost between $100 and $900, to help consumers determine the
origins of their ancestors. More than 460,000 people have purchased the
tests during the past six years and public interest is growing.
The researchers argue that the assumptions and limitations of the
tests make them less informative than many realize, and
commercialization has led to misleading practices that reinforce
misconceptions.
Here are some of the tests' limitations identified by Bolnick and her co-authors:
- Most tests trace only a few of your ancestors and a small portion of your DNA,
- Tests are unlikely to identify all of the groups or locations around the world where a test-taker's relatives are found,
- Tests may report false negatives or false positives,
- Limited sample databases mean test results are subject to misinterpretation,
- There is no clear connection between DNA and racial/ethnic identity,
- Tests cannot determine exactly where ancestors lived or what ethnic identity they held.
Consumers often have deeply personal reasons for taking the tests.
Some hope to validate genealogical records or fill in gaps in family
histories. Others are searching for a connection to specific groups or
places in Eurasia or Africa. Many African Americans hope the tests will
help them trace ancestral links lost during the transatlantic slave
trade. Other Americans have taken the tests in hope of obtaining Native
American tribal affiliation or to challenge tribal membership
decisions. However, an individual's social or ethnic identity does not
always match his or her genetic ancestry.
"Not all companies make clear the limitations and assumptions
underlying these tests," Bolnick said. "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 Science or read The University of Texas at Austin feature story "Deep Roots?" online.
For more information contact: Deborah Bolnick, assistant professor of anthropology, 512-471-8514; Jennifer McAndrew, public affairs specialist, College of Liberal Arts, 512-232-4730.
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