Bill Newman, professor of translational genomic medicine in the Manchester centre for genomic medicine at the University of Manchester, and chair of the British Society of Genetic Medicine, says that such tests in this context simply don’t make sense and that, usually, telomere testing would only be used in in-depth studies of ageing and diseases associated with ageing. “There’s some really brilliant work going on, by some of the best biologists in the world,” says Newman, citing Elizabeth Blackburn, who won the 2009 Nobel prize for medicine for her work on telomeres. “But there’s no evidence whatsoever that measuring a person’s telomeres gives any indication about their health – or beauty, intelligence, or anything else that might be listed on these sites.”
This is one of the most common questions and the most difficult to answer. There are approximately forty companies currently offering DNA testing to determine genealogy and ethnicity. None of these companies have shared their data, no standards of accuracy have been agree on and independent scientists have not yet validated these methods. Some experts believe the results are valid, others feel they must be viewed with some skepticism. Once you receive your results, you must decide on the validity based on your knowledge of your family history.
Most of the services we tested use genotyping to read your DNA. Genotyping looks for specific markers in your genetic code. For something like ancestry testing, genotyping is effective because it identifies known variants in your DNA. Scientifically speaking, genotyping’s weakness is that it can only recognize previously identified markers. This is one reason DNA tests’ accuracy relies so heavily on the DNA database size; there must be enough information available and identified genetic variants in the database to recognize new customers’ markers.
The spit is for one of the home genetic-testing kits I’m sampling. A growing number of these kits (brands such as 23andMe, DNAFit, Thriva, MyHeritage DNA, and Orig3n) promise to unlock the mystery of your genomes, variously explaining everything from ancestry, residual Neanderthal variants, “bioinformatics” for fitness, weight loss and skincare, to more random genetic predispositions, denoting, say, the dimensions of your earlobes or the consistency of your earwax.