A prehistoric chewing gum

The chewing gum was obtained from birch bark • THEIS JENSEN / UNIVERSITY OF COPENHAGEN / PRESS SERVICE

It's amazing what a piece of birch chewed 5,700 years ago can reveal! This prehistoric "chewing gum" was discovered during archaeological excavations on the island of Lolland, in southern Denmark, a place where the mud preserves the organic remains particularly well, which has made it possible to preserve in a remarkable way the DNA of its owner. Or rather its owner, because the study showed that it was a woman, who had brown hair and blue eyes, and who had just eaten duck and hazelnuts! She was genetically close to the hunter-gatherers of Western Europe. The small traces of teeth that the "chewer" left in the dough indicate that she was young. The study of this genome, the first whole ancient human extracted from an element other than bones, was carried out in Denmark by the Global Institute of the University of Copenhagen.

The "chewing gum" was actually a blackish paste obtained by heating birch bark. It was used as glue in the manufacture of tools such as arrowheads, but was probably also chewed, because this tree has antiseptic properties that can relieve a toothache, for example. These properties have also made it possible to trap DNA "by inhibiting both its microbial and chemical decomposition", according to the researchers.

Microbial flora

Microbial DNA also remained in the mouth flora of the eater, and the families of bacteria identified are considered part of the normal microflora of the human mouth and upper respiratory tract. Some of these bacteria cause problems like gum inflammation or pneumonia. Which could help understand how pathogens evolved and spread. The researchers also found DNA from duck and hazelnut, which led them to believe that the young woman had consumed them. Chewing gums of this kind had been discovered a few months earlier in Sweden, dating back 9,000 years, but their DNA had been less verbose.