A half-million Americans will spend $100 to $1,000 per person for genetic genealogy tests this year, according to the American Society of Human Genetics (ASHG) <www.ashg.org>. But will all those people really understand what their genetic tests are telling them?
Not if you ask the ASHG, whose 8,000 members include geneticists, scholars, genetic counselors, nurses and others. In a statement issued at its annual meeting late last year, the organization says genetic genealogy testing companies aren’t doing enough to make sure consumers know the limitations of DNA testing. What exactly are those limitations? We’ll explain the issues at the center of this controversy.
ASHG faults tests designed to determine ethnic ancestry, not those that estimate whether you’re related to someone or assign you to a haplogroup. “Rarely can definitive conclusions about ancestry be made beyond the assessment of whether putative close relatives are or are not related,” reports the statement.
Ethnic DNA tests analyze your DNA (see page 48) and compare it to a reference database that uses DNA samples from modern-day individuals to represent populations that existed eons ago. One problem, according to the ASHG, is that the tests analyze a tiny slice of your DNA. And due to historical population movements, the DNA in reference databases may not match the DNA of a given area’s original residents. The statement says these databases, in fact, “reflect a woefully incomplete sampling of human genetic diversity.”
In addition, the ASHG says, genetic genealogy companies operate without a governing body. No standards regulate statistical analysis and how results are reported to consumers. “Perhaps the most important aspect of reporting confidence … is to accurately convey the level of uncertainty in the interpretations and to convey the real meaning of that uncertainty.”
“A number of [consumer and industry groups] have expressed that they are glad the society is addressing the plethora of issues surrounding genetic ancestry testing,” says ASHG spokesperson Kristin Long.
Back in 2007, the New York Times doubted the accuracy of ethnic DNA tests after its reporter received varied and conflicting test results from five companies. In the article, Bert Ely, a geneticist who helped start the African-American DNA Roots Project with high hopes in 2000, shared his finding that most African-Americans have genetic similarities to numerous ethnic groups in Africa—making it impossible to match African-Americans with a single group.
An article in the Oct. 19, 2007, Science magazine cited problems including limited information in DNA reference databases and proprietary databases that make it hard to verify customers’ test results. In addition, the authors said, because tests trace a small percentage of a person’s ancestors, they can’t accurately pinpoint their geographic origins or the specific ethnic group they belonged to.
The issues can be confusing, says Blaine Bettinger, a genealogist whose Ph.D. in biochemistry led him to blog at The Genetic Genealogist
. “Customers often assume that the percentages are final and represent an accurate picture of their entire genome.”
To test or not to test
The complex science and technical terms trip up many researchers. “Of course, sometimes it is challenging to explain the science to a customer who does not have a science background, as it would be in any discipline,” says Max Blankfeld, vice president of Family Tree DNA. “It’s exacerbated when people come to us after having received wrong information from other companies and in the media.”
But now that the genetic genealogy industry has aged a decade or so, its customer education has improved, says Scott Woodward, Ph.D., executive director of the Sorenson Molecular Genealogy Foundation
. “Genetic genealogy companies are doing a better job today than they were a couple of years ago.”
It’s a case of a few bad apples spoiling the bushel, Blankfeld says. “We do an excellent job of telling people why they should not test and when they should test.”
Bettinger isn’t sure government oversight is the answer, saying those who recommend it “overlook the strong community of test-takers who are constantly reviewing, analyzing and critiquing results. The work of this community serves as an important check on testing companies.”
What is the answer? ASHG may explore that question at a roundtable meeting this year. “Representatives from industry, the federal government, associations, professional membership societies, and consumer and advocacy groups would be called together to discuss the major issues related to genetic ancestry testing,” Long says.
Bettinger encourages consumers to do their own homework. “While some test-takers may have the scientific background to understand all the benefits and limitations of DNA testing, many do not, and should educate themselves before testing.”
In the future, genealogists can worry less about test limitations. “There will be increased testing of autosomal markers that will allow inferences about other ancestors,” Woodward says. That is, a test will be able to tell you about ancestors not on your direct paternal or maternal lines.
Depending on your research goals, you may want to consider postponing that autosomal DNA test. “I tell people to wait a few years unless they’re interested in being a pioneer in the field or are simply too curious,” says Bettinger. “The information a person can obtain today is a drop in the bucket compared to what that person will learn from a similarly priced test five to 10 years from now.”
Here’s a summary of how the ASGH wants the ancestry testing industry to change its ways. The group’s ancestry testing committee will follow up with a more in-depth “white paper” this spring.
The genetic genealogy industry should make a greater effort to clarify the limitations of ancestry testing. Consumers must strive to better understand the implications and limitations of these assessments.
Additional research is needed to further understand how the accuracy of test results is affected by the makeup of existing human DNA databases, geographical patterns of human diversity, chromosomal marker selection and statistical methods.
Guidelines should be developed to facilitate explanation and counseling for ancestry testing.
Scientists analyzing genetic ancestry test results should take into account the historical, sociopolitical and cultural contexts under which human genetics evolved.
Ways to increase accountability of the ancestry testing industry should be explored.