With genetic testing for health, ancestry, paternity and more becoming increasingly popular, many people are left wondering: exactly how accurate are DNA tests? Whether you are taking a DNA test to build your extended DNA family tree with an AncestryDNA testing kit, or want precise information on hereditary health conditions with 23andMe, it is important to understand how accurate genetic tests are, and what information we can rely upon.
How accurate DNA tests are relies greatly upon the kind of test being taken. “The accuracy of results depends on the specific question we ask, and on how complex is the genetics behind a trait,” Sergio Pistoi, a molecular biologist and author of “DNA Nation” (Crux Publishing, rheumatoid arthritis and pregnancy and prednisone 2019), told Live Science. For example, tests for traits that depend on a single gene, called monogenic traits, provide much more reliable results, because you can see whether a disease-causing mutation or another trait is present.
How accurate are DNA tests for ancestry?
Ancestry testing services from companies such as AncestryDNA draw upon a large body of data from millions of people. These tests purport to reveal our genetic identities based on ethnicity or geographical location.
However, Pistoi warns that while these tests can be fascinating, and can present the vast diversity of humanity’s genetic history, we should be wary of what these results really tell us. “Saying you are 30 percent East Asian or Celtic is just a statistical inference about your genome and hardly reflects your real ancestry,” Pistoi wrote. “Nevertheless, these tests are having a profound impact on self-perception, and this is why they are so successful. I am mostly interested in exploring the social consequences of this technology.”