I don’t often read about science, but the field of human evolution fascinates me. I find it almost impossible to imagine the sheer expanse of time that has passed between the development of the first modern humans and the present day. It makes my head hurt. Things that seem so important in everyday life suddenly dwindle into nothingness when confronted with the epic story of humanity. But, if you turn the question on its head, you realise that humans really haven’t been around that long at all compared to other species with much longer innings – the dinosaurs, obviously, but even our extinct cousins the Neanderthals. Keep thinking, though, because the really staggering thought is actually the most obvious. Every single one of us alive today has direct ancestors who learned to make fire, who hunted mammoths, who made flint knives. It wasn’t just our general species that descended from these people. You did. I did. If there was a way to trace your family tree back far enough, through the Ice Age and beyond, into a world that looked completely different to the one we know today – if that was possible, you could find out who your ancestors were. Well, it is possible. Bryan Sykes and his fellow geneticists have done it. And this is the story of their work.