This week Gizmodo published an article about Genetics: “How DNA Testing Botched My Family’s Heritage, and Probably Yours, Too.” The author’s grandfather was an orphan, whose mother was later identified to him as a Syrian woman. The author finds that DNA testing for herself and members of her family give ethnicity results that are not what she expected.
The author submits her DNA to AncestryDNA, 23andMe, and National Geographic. She finds, of course, that the results vary considerably between the three companies, and wonders what is going on. The article includes a good quote from geneticist Adam Rutherford: “They’re not telling you where your DNA comes from in the past. They’re telling you where on Earth your DNA is from today.” She rephrases it in her own words: “Spit in a tube and find out where on the planet it’s statistically probable that you share ancestry with today.” This is a point that we all should remember as we consider ethnicity estimates. The author is informed that results are generally good to the continent level, and that the tests results get better as the science does. These are good, basic facts that all DNA testers should know.
The main point that the article misses, however, is that DNA testing can be used to identify the grandfather’s father. It requires analyzing trees from the relative match lists and target-testing individuals. This is the real power of DNA testing. But overall this is still worth a read.