I have had my mother's wing of my genetic ancestry analyzed by the tracing service and there it all is: the arrow moving northward from the African savannah, skirting the Mediterranean by way of the Levant, and passing through Eastern and Central Europe before crossing to the British Isles. And all of this knowable by an analysis of the cells on the inside of my mouth. I almost prefer the more rambling and indirect and journalistic investigation, which seems somehow less... deterministic.