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Reliability of DNA Testing for Ethnic Heritage

by Rosalyn Goh

Many people attempt to trace their ancestral lineage through a paper trail and find the search to be, at times, frustrating and limiting. Companies that offer genetic ancestry testing seem to be the solution. However, many experts on genetics have argued these companies may not be as accurate as they claim. The American Society of Human Genetics published a statement on genetic ancestry and potential accuracy issues testing in 2008.

Types Of Testing

According to the American Society of Human Genetics, there are four types of DNA ancestry testing available. Ancestry informative markers show differences between certain ancestral populations, mitochondrial DNA analysis shows maternal lineage, Y-chromosome markers show paternal lineage and genome-wide single nucleotide polymorphisms show both maternal and paternal lineage. According to the Washington Times, the most popular test available currently tests the Y-chromosome for paternal lineage. However, this test can only be used with males.

Database Limitations

There can be problems with the size of the database these DNA testing companies can reference. According to Dr. Ed McCabe, a geneticist at UCLA and the president of the American Society of Human Genetics (ASHG), database size matters because these companies match DNA makeup to other samples from around the world. He goes on to state, "Some of these companies have outstanding databases they can use to help place ancestry and others have databases that aren't as large and as robust in terms of providing ancestry." According to Dr. McCabe, companies are taking current DNA samples and extrapolating that information to apply to historical populations within the same area. The problem is some of those populations may have been forced to move in the past or died off due to a catastrophe. Contemporary DNA samples may not be what existed in that area historically. However, Dr. McCabe goes on to state that improvements in technology have improved test accuracy.

Conflicting Test Results

According to an article published in the Washington Times, there have been conflicting test results sent back by DNA ancestry testing companies reported by others in the media. Henry Louis Gates Jr., a professor of African-American studies at Harvard, sent in for test results and received one report stating he was Egyptian and another stating he was European. As written in the Washington Times, Edward Ball, writer of "The Genetic Strand," states he had some hair samples tested and one company reported he was American Indian. Another company told him he was from Northern Europe and another company reported he was African, but not American Indian.

Implications

People seeking test results may become shocked, disappointed, angry or sad if they receive results that are unexpected. Many seeking tests are not aware of the potential inaccuracy of the results received. Other concerns can be related to certain diseases being linked to certain racial populations. These concerns can be unwarranted. For others, such as Native Americans, testing can be problematic, as people may seek privileges as related to ethnic origin based on genetic ancestry testing. In the future, people may seek to change information on government forms or seek dual citizenship based on the results.

ASHG Recommendations

The American Society of Human Genetics recommends that both academia and companies offering DNA ancestry testing make the public more aware of the limitations of such tests. Additional research must be done to determine how accurate testing results are in relation to the databases utilized. Guidelines should be created for those who receive results to educate them further on ancestry estimation. Greater accountability for this industry niche should be developed.

About the Author

Based in Southern California, Rosalyn Goh graduated with a B.A. in creative writing from the University of California, Riverside in 2005. Though she is new to writing articles for publishing, she has written personal blogs of her own since 2004 on various subjects such as spirituality and interpersonal relationships.

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