You can’t get away with sticking gum to the underside of your school desk anymore, as researchers from Stockholm University have developed a technique to analyze the DNA in dried-out chewing gum in order to determine who chewed it. However, rather than using their method to identify low-level vandals, the team has managed to recreate a picture of life as a hunter-gatherer in Neolithic Scandinavia.
The ancient masticates were retrieved from a Stone Age hunting and fishing site called Huseby Klev, which sits on the west coast of Sweden and was first excavated in the 1990s. Unfortunately, most of the human bones had long since degraded by the time the site was unearthed, meaning researchers couldn’t analyze any DNA from the original inhabitants.
However, the ancient occupants did leave behind lumps of dried-out chewing gum, made from birch bark tar. Rather than using it to freshen their breath, the hunters chewed this rubbery material to create an adhesive for binding tools and weapons.
Dated to between 9,540 and 9,880 years old, these well-chewed gums contained saliva from which the researchers were able to extract the oldest DNA ever sequenced from this region. Amazingly, despite the passage of 10 millennia, the team was still able to identify three individuals who had spat the samples out, of which two were female and one was male.
This discovery provides a fascinating insight into gender roles within Stone Age Scandinavian culture, suggesting that tool production was an activity undertaken by both men and women. Furthermore, the discovery of milk teeth markings in the gum indicates that children may also have been involved in this process.
Writing in the journal Communications Biology, the authors note that the discovery also reveals how the region acted as a crossroads for western and eastern genetics and culture, as the inhabitants of Huseby Klev displayed a strong genetic affinity to other western European groups, while much of their technology appears to have been shaped by eastern Eurasian influences.
Summing up the significance of these findings, study author Per Persson said in a statement that "DNA from these ancient chewing gums [has] an enormous potential not only for tracing the origin and movement of peoples [a] long time ago, but also for providing insights in[to] their social relations, diseases and food."