Genetic ancestry testing has become increasingly familiar in the past decade. The expansion from small companies investigating particular communities to huge multinational biotech organizations, such as 23andme and Ancestry, has been swift and, frankly, enormous. Ancestry currently has more than 22 million individual DNA records in their commercial database, with smaller organizations such as MyHeritage holding around 6 million. Size matters in this market, as the bigger the database, the more fine-grained detail the service can offer. The tools available to interpret data are developing at speed, with Ancestry now using “SideView” to suggest which parent contributed which parts to an individual DNA (this is akin to the “Lazarus” tool that was developed by the Gedmatch family history community). Their “DNA Traits” tool suggests that genetic data can explain or reveal foundational ‘truths’ about a user. For public historians, the challenge of these new technologies and what they mean for contemporary historical sensibilities is acute and widespread. DNA, as Sarah Abel writes, “is increasingly being used as a tool for piecing together individual and collective histories”.