How Accurate are Genetic Ancestry Tests?
Genetic ancestry tests have become popular with genealogists wanting to know where their ancestors lived. About thirty companies now supply direct-to-consumer tests that make such claims. Some also make health-related claims. Since these tests became available through the internet, there have been ongoing concerns over the usefulness and accuracy of such tests as well as privacy concerns as to the ownership of the results.
Various government regulators have begun to take action and some jurisdictions are starting to require companies to be licensed before they can offer genetic ancestry tests to the public (see “California Licensing Genetic Testing”). Now, the American Society of Human Genetics (ASHG) has waded into the debate. ASHG is the primary scientific organization worldwide for researchers who study human genetics.
ASHG has released a statement that raises serious questions and concerns about genetic ancestry tests. In response to the accuracy of such tests, the ASHG had this to say: “Many people pursue genetic ancestry testing because they wish to find out more information about either the local populations or broad geographical regions in which their ancestors lived. However, the power of commercial genetic tests to answer such questions is limited…” As well, ASHG raised concerns that such tests “foster questions about privacy and the security of ancestry-related databases”.
The accuracy of genetic ancestry tests depends on many factors including the nature of the genetic markers used in the test, the number of markers used and the statistical methods applied to the results. Unfortunately, the genetic ancestry test market lacks basic industry standards and quality control assurances both for the results of the genetic tests and for the personal privacy of the individual test results. This issue has been compounded as the cost for genetic ancestry tests has fallen rapidly and the 30 some companies that provide such tests compete vigorously amongst themselves.
The ASHG statement also points out the results of genetic ancestry tests can have unexpected psychological results including “shock, disbelief, denial, anxiety, anger, fear” when a person’s ancestry (at least as determined by the genetic test, which may be wrong) is different from what was expected. The potential for emotional distress can be significant, not just for the person who had the test, but also for their nearest living relatives.
The ASHG recommends that if you are interested in genetic ancestry tests, you should become an informed consumer and make sure you understand the implications and limitations of such tests.
The complete ASHG statement can be found here. ASHG plans to release a full report on genetic ancestry testing in 2009.