As a molecular geneticist married to a cultural anthropologist, I often come across the question of ancestry testing. What can it tell me? How reliable is it? As with much about DNA, many people seem to think that it is more reliable than it actually is. I found the PBS special “African American Lives,” which uncritically presented DNA evidence for the origins of several prominent African-Americans, especially disturbing in this regard.
I was therefore very happy to see an article in last week’s Science on “The Science and Business of Genetic Ancestry Testing ,” make some excellent points. It should be read by anyone interested in this field.
I will just provide some excerpts:
Most significantly, and most generally, these tests “cannot pinpoint the place of origin or social affiliation of even one ancestor with exact certainty. Although wider sampling and technological advancements may help (16), many of the tests’ problems will remain.”
“An allele could have been inherited from a population in which it is less common. Consequently, many consumers do not realize that the tests are probabilistic and can reach incorrect conclusions.”
“For instance, the AncestryByDNA test suggests that most people from the Middle East, India, and the Mediterranean region of Europe have Native American ancestry (15). Because no archaeological, genetic, or historical evidence supports this suggestion, the test probably considers some markers to be diagnostic of Native American ancestry when, in fact, they are not.”