DNA ancestry tests are bullshit

Adam Rutherford's amazing book A Brief History of Everyone Who Ever Lived is on shelves in the USA now; debunking the absurd claims made by genetics testing companies — claims about your distant relationship to ancient kings or the percentage of your genes that came from Vikings.

Rutherford's quest to debunk the highly profitable "genetic astrology" industry has some staunch allies, including the wonderful Sense About Science people (previously), including Steve Jones, Emeritus Professor of Human Genetics at UCL and Prof Mark Thomas.

Rutherford's book is a really clear — and often very funny! — explanation of what genomics is useful for: analyzing whole populations and species and discovering what is and isn't a heritable trait, adding nuance to the stories of heredity and evolution, and debunking old eugenic idiocies like "noble blood" and the idea that human beings can be divided into "races."

If you want to get a sense of just how terrible these old ideas are, check out this week's podcast of Rob Newman's "Total Eclipse of Descartes," a standup routine in which Newman explains how junk eugenic science and old scientific frauds have been used to make education into a toxic mess.

A warning about the accuracy of the tests was made by the Sense About Science campaign group, which said "such histories are either so general as to be personally meaningless or they are just speculation from thin evidence."

The warning was backed by a number of leading genetics experts. Steve Jones, Emeritus Professor of Human Genetics at UCL said: "On a long trudge through history – two parents, four great-grandparents, and so on – very soon everyone runs out of ancestors and has to share them.

"As a result, almost every Briton is a descendant of Viking hordes, Roman legions, African migrants, Indian Brahmins, or anyone else they fancy."

His colleague Prof Mark Thomas said: "These claims are usually planted by the companies that provide these so-called tests and are not backed up by published scientific research. This is business, and the business is genetic astrology."

DNA ancestry tests branded 'meaningless' [Nick Collins/Telegraph]