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ASHG recommendations on ancestral / genealogical DTC genetic testing
The ASHG statement on ancestry testing noted their major concern that there is no quality assurance system or “even a mechanism to couple market performance with anything relating to accuracy”, although this accuracy could vary to a significant degree depending on the reference population databases used for analysis. The ASHG also notes that even the best databases “reflect a woefully incomplete sampling of human genetic diversity”. In terms of potential health implications of ancestry testing, the ASHG notes the current lack of understanding about how genetic ancestry related to individual and population health, along with a common assumption that racial/ethnic identity may be a key determinant of health outcomes. They urge caution in the interpretation and clinical application of results from ancestry and related DTC genetic tests. The personal and societal implications of testing are noted to be potentially complex, raising a range of political, legal, psychological, social and ethical issues.
President elect of the ASHG Edward McCabe commented: “Consumers, as well as scientists, must remember that ancestry-testing inferences are fallible, and that over-interpretation or misinterpretation can happen…Inaccurate results may be confusing and life-changing, therefore greater efforts are needed to make the limitations of ancestry testing more explicit” (see press release).
- Clearer delineation of the current limitations of ancestry determination by industry and academia to make them clearer to consumers, the scientific community, and the public at large; the public should access and take note of information.
- Further research to clarify the extent to which the accuracy of genetic ancestry estimation is influenced by the individuals represented in existing databases, geographical patterns of human diversity, marker selection and statistical methods.
- Assessment of the complex consequences of ancestry estimation for people, families, and populations, and the development of guidelines to facilitate explanation and/or counselling about ancestry estimation in research, DTC and health care settings.
- Conferral of scientists performing and interpreting genetic ancestry tests with experts in the historical, sociopolitical and cultural contexts of such testing.
- Establishment of mechanisms for greater accountability of the DTC ancestry testing industry.
Internet-based ancestry testing is available DTC internationally; for example, MyHeritage offers testing including a Y-chromosome test to identify paternal descent, a mitochondrial DNA test to identify maternal descent. FamilyTreeDNA chief executive Bennett Greenspan has reportedly said of their own service: "The biggest problem is finding out your brother isn't your brother or your father isn't your father. But we don't deal with that…you'd be more likely to find out that your great grandfather was adopted or that there was false paternity" (see Guardian news article).