Adam Rutherford is a former geneticist, now a science writer and broadcaster. He is on BBC Radio 4’s Inside Science, and his most recent book, Creation (Viking 2013), concerning the origin of life, and genetic engineering and synthetic biology.
Rutherford thinks a crystal ball might be just as good as direct-to-consumer genetic testing when it comes to the ‘genetic astrology’ of linking the DNA of modern humans to their famous ancestors.
He writes, “This is merely a numbers game. You have two parents, four grandparents, eight great-grandparents, and so on. But this ancestral expansion is not borne back ceaselessly into the past. If it were, your family tree when Charlemagne was Le Grand Fromage would harbour more than a billion ancestors – more people than were alive then. What this means is that pedigrees begin to fold in on themselves a few generations back, and become less arboreal, and more web-like. In 2013, geneticists Peter Ralph and Graham Coop showed that all Europeans are descended from exactly the same people. Basically, everyone alive in the ninth century who left descendants is the ancestor of every living European today, including Charlemagne, Drogo, Pippin and Hugh. Quel dommage.”