DNA of animal skins used as parchment for medieval manuscripts could reveal where the texts were made, reports Brandon Keim for the Wired Science blog. A team of two brothers, both academics, took skin samples from five pages of a 15th century French prayer book to find that the preserved mtDNA in the pages came from two closely related calves. The work is still in early stages and needs additional funding (tests run between $800 and $1000 per sample), but it’s likely a method that would take the guesswork out of pinpointing when and where manuscripts date from. And, it’s possible to create a DNA database from manuscripts of known age and origin, says the story. “When did books become a business, as opposed to something monks did? That’s a puzzle nobody knows,” says Stinson. “This could be a social history of producing a good for trade.”