ASHG Releases Ancestry Testing Statement Emphasizing Interpretation

The American Society for Human Genetics (ASHG) has released a statement outlining a set of recommendations for genetic ancestry testing.At a press briefing on Thursday, members of the ASHG Ancestry Testing Task Force Committee discussed two main themes: the need for clear communication about the limitations of genetic ancestry testing, and the need for researchers and companies doing this type of testing to engage with the social sciences to put results in context.Michael Bamshad of the University of Washington School of Medicine discussed at length the need for people to understand that ancestry assignments based on genetics are inherently uncertain and can be affected by several factors, including the reference populations used in the analysis, the type and number of genetic markers analyzed, and the statistical methods employed.ASHG president Aravinda Chakravarti further emphasized that questions about the “accuracy” of genetic ancestry testing are aimed at the interpretation of the genetic data, not at the actual DNA analysis.Task force co-chair Charmaine Royal of the Duke University Institute for Genome Sciences and Policy addressed the committee’s concerns about the psychological impacts of genetic ancestry testing, especially as related to issues of identity.23andMe Senior Director of Research Dr. Joanna Mountain had a chance to talk with some of the members of the ASHG Ancestry Testing Task force about their statement.“Members of the panel emphasized to me that their primary goal was to raise a set of concerns around identification of ancestry through genetics,” said Mountain.“Because several of us at 23andMe were previously aware of these concerns, we developed our ancestry features with those concerns in mind. For instance, we consider a large number of markers for all the chromosomes of the human genome, including the mitochondrial genome. We also avoid being overly precise in reporting an individual’s ancestry. And we are currently creating educational tools to help our customers understand how genetic information can be informative about ancestry.”The speakers stressed several times that their statement was not aimed just at consumer companies offering genetic ancestry testing, but also at academic researchers in the field.Unfortunately, Mountain said, the ASHG guidelines leave out some of the potential benefits of ancestry genetic testing.“For instance, ASHG President-Elect Ed McCabe encouraged the audience to ask their family elders about family history over Thanksgiving, as an alternative to learning about ancestry through genetics. But individuals who have signed up for 23andMe’s service may find themselves far more motivated to discuss family history than they would before seeing their genetic data.”For a more thorough analysis from a genetic genealogist’s point of view, click here.McCabe said the statement released this week is a preliminary document. The committee expects to issue a more detailed report in Spring 2009.
  • maxxroth

    The recent report by the American Society of Human Genetics on its concerns about ancestry testing is timely. Clearly consumers, often with limited science backgrounds, need to know what they are getting and how useful the product they are using is to them. As is pointed out in the report, on occasion, a few companies or consumers may over stretch the value of such testing results. As a geneticist, I remind interested users that these tests have limits to their value. Using Y chromosome typing for male lineage to suggest relationships among people with the same last name or similar last names is useful. So is the use of mitochondrial genotyping in female lineages to demonstrate more distant relationships among individuals. Predicting geographic origin or implying race can be just that — a prediction since data bases are often limited and considerable human migration and intermarriage makes use of some genes/alleles risky predictors of origin. Such predictions by there very nature have some risk and are not always reproducible.

    It is important and prudent to not muddy the waters by somehow linking DNA genealogy and medical genomics. These are both very important fields, especially the medical genomics field, with over 20 companies entering the market place. There is no doubt that both fields must have competent companies but the implications of missed or incorrect diagnoses by a medical genomics company is far different from the tracing of one’s genealogy by the use of DNA. We must separate medical genetics from the recreational pursuit of ancestry through DNA. Both require good science and competent practitioners and there are such companies in each field. Let us not punish these companies and their customers by over zealous regulation. The ASHG needs to work and develop close cooperation between all interested parties.

    I urge consumers to examine companies and find those with trained population geneticists, statisticians and those with genetic training, before purchasing tests and services. One such company, FamilyTreeDNA, is a leader in the industry and its results are based on good science. FamilyTreeDNA uses population geneticists and world recognized scientists on its Scientific Advisory Board and endeavors to use only the most proven methods in its genealogy work. It offers further services to ensure customers receive results that are specific to the tests they have ordered and not unfounded predictions of race or specific geographical origin. Undoubtedly other companies with equally well trained scientists and motives also exist. All qualified parties and organizations should work together such that the public is educated in its pursuit of knowledge and its trust is well founded.

    Max Rothschild, PhD
    Iowa State University