Those of us who signed up for DNA testing kits from 23andMe did so thinking we’d unlock deep ancestral secrets. Maybe we’d discover we had royal blood, or finally settle the family debate over whether great-grandpa Dmitri was really Kenyan after all. Often, the results were far less conclusive: the tests revealed that we were 12 per cent Neanderthal, distantly related to Genghis Khan’s less-heralded cousin, Mungo, and possibly allergic to liquorice.