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What is genetic ancestry testing?
Genetic ancestry testing, or genetic genealogy, is a way for people interested in family history (genealogy) to go beyond what they can learn from relatives or from historical documentation. Examination of DNA variations can provide clues about where a person’s ancestors might have come from and about relationships between families. Certain patterns of genetic variation are often shared among people of particular backgrounds. The more closely related two individuals, families, or populations are, the more patterns of variation they typically share.
Three types of genetic ancestry testing are commonly used for genealogy:
Genetic ancestry testing has a number of limitations. Test providers compare individuals’ test results to different databases of previous tests, so ethnicity estimates may not be consistent from one provider to another. Also, because most human populations have migrated many times throughout their history and mixed with nearby groups, ethnicity estimates based on genetic testing may differ from an individual’s expectations. In ethnic groups with a smaller range of genetic variation due to the group’s size and history, most members share many SNPs, and it may be difficult to distinguish people who have a relatively recent common ancestor, such as fourth cousins, from the group as a whole.
Genetic ancestry testing is offered by several companies and organizations. Most companies provide online forums and other services to allow people who have been tested to share and discuss their results with others, which may allow them to discover previously unknown relationships. On a larger scale, combined genetic ancestry test results from many people can be used by scientists to explore the history of populations as they arose, migrated, and mixed with other groups.
For more information about genetic ancestry testing:
The British Broadcasting Company offers an introductory article on genetic
The University of Utah provides video
The International Society of Genetic
The American Society of Human Genetics (ASHG) developed a position paper on ancestry
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