Many millions of people have now had commercial testing for their ancestral lineage. Such testing can be of varying complexity. The less complex varieties simply use mitochondrial DNA and the Y chromosome to track the maternal and paternal ancestral lines respectively. The more complex form uses variations across the entire DNA spectrum.

A recent JAMA paper argues that there is some medical value in such testing.[1] For example, it may indicate that an Indian person living in America is at risk of cystic fibrosis because of maternal and paternal European ancestry. That sounds like a weak argument. More important, ancestral testing can improve the specificity of genome wide association studies and improve the prognostic value of genes that predispose to disease. That is to say, that the same genetic signature may have a different prognostic implication according to its ancestry. This will be important scientifically and even medically if genetic testing for polygenic disease becomes more widespread.

Not mentioned in the article is another value of testing, genetic or otherwise. This value lies in the news worthiness of the information. It is simply interesting to have an insight into one’s geographic origins. The ARC WM director is contemplating such testing.

Richard Lilford, ARC WM Director

Reference:

1. Jorde LB & Bamshad MJ. Genetic Ancestry Testing: What Is It and Why Is It Important? JAMA. 2020; 323(11): 1089-90.