A face from ancient gum

Scientists have re-created the face of an ancient hunter-gatherer using DNA extracted from a piece of “chewing gum” that was spat out some 5,600 years ago. The lump of chewed birch tar was found at a site in southern Denmark, alongside pieces of wood and wild animal bones. Made by heating birch tree bark, the tar has been employed as an adhesive for hundreds of thousands of years. Neolithic humans used the sticky substance to glue arrowheads to arrow shafts and repair stone tools. Many pieces of tar found at archaeological sites contain tooth marks, suggesting the gum—which has antiseptic properties—was also used to treat tooth pain. From the Danish sample, researchers were able to re-create the entire genomic sequence of the chewer: a woman who had dark skin, dark hair, and blue eyes. It is the first time that scientists have extracted an entire human genome from anything other than human bones. “There are periods where we don’t have any bones, but birch pitch survives very well,” study co-author Theis Jensen tells The Guardian (U.K.). “It’s very intimate. You get so much information.” ■