Drawing inspired by information extracted from the Stone Age

A new Swedish study has shown that DNA found in quantities of chewing gum by Stone Age teenagers, found at a 9,700-year-old archaeological site in Sweden, provides insights into oral diseases of that era. The study, conducted by a team of paleontologists from Stockholm University and published in the journal Scientific Reports, provides information about the diet of these prehistoric hunter-gatherers. "The gum we sampled was probably chewed by adolescent girls and boys. There was a specific age at which they did it," study co-author Anders Gutherström told AFP on Tuesday.

 The pieces of saliva-soaked birch bark, which bear tooth marks, were found 30 years ago alongside bones at the Husby Kliff site north of what is now Gothenburg. It is one of the oldest archaeological sites containing human bones in Scandinavia. "We think that this gum was used as a glue to hold things together. It is also possible that they chewed it for pleasure or because they attributed it to medicinal properties," the researcher added.

In 2019, a first study of chewing gum fragments made it possible to determine the genetic makeup of individuals. Now, traces of non-human DNA are being detected.

“We found a large number of bacteria that indicate a severe case of periodontitis, a serious gum infection,” said Anders Götherström.

“In one case, we know it was a young woman, who probably started losing her teeth after using this gum. This infection must have been very painful.”

The results also shed light on the diet of this Scandinavian community, which was varied, including hazelnuts, deer and trout. Traces of apple, duck and fox DNA were also found in the analyses.

“When we analyze a human bone, we extract human DNA. But what is particularly interesting about this gum is that there is a trace of what was eaten before, and the bacteria of the person who carried it. There is no other way to achieve these results,” Götherström continued.

"We see the imprint that adolescent teeth left on chewing gum thousands of years ago," he concluded. "For us archaeologists, there is also a philosophical dimension, which is the relationship between man, DNA and the artifact."