Power and Limitations of Inferring Genetic Ancestry

The recent emergence of technologies that capture and analyse genetic variation patterns obtained from a person's DNA sample has led to numerous academic and commercial endeavours to infer individuals' ancestries. In theory, a person's genome contains a wealth of readily accessible information regarding their ancestors, despite only some of our ancestors contributing to the DNA we carry. This makes genetic tests an attractive alternative to the painstaking reconstruction of family trees or directly contacting long-lost relations, particularly when, unless there are notable individuals in the tree, historical and genealogical records tend to diminish in frequency with each generation. However, while powerful, there are limits to what genetic data can unearth, as well as important assumptions underlying these analyses.

This review describes some of the early history and latest advances in techniques and data used to infer ancestry using genetics, highlighting both the power and limitations of current studies.

While genetics is a powerful means of exploring aspects of people's ancestry, a stronger focus on conveying uncertainty will allow both academics and non-academics to avoid the ever-present risks of over-interpretation.