DNA From 10,000-Year-Old Scandinavian Chewing Gum Reveals Stone Age Diet

Conny Waters - AncientPages.com - In the early 1990s, excavations took place at Huseby-Klev, an early Mesolithic hunter-fisher site on the Swedish west coast, where a piece of ancient chewing gum was found. The masticates were made out of birch bark tar and used as glue in tool production and other types of technology during the Stone Age. However, at the time, it was impossible to conduct a proper analysis, and the discovery was forgotten for a long time.

Photo from the excavation site Huseby Klev at the Swedish west coast. Credit: Bengt Nordquist

Our History Is Visible In The DNA We Carry With Us

Some years ago, scientists announced they had examined the chewing gum. The research team determined the chewing gum from Huseby Klev was left behind by the first humans who settled in Scandinavia about 10,000 years ago. The find was remarkable because the oldest Scandinavian DNA had been found in this ancient chewing gum.

"Demography analysis suggests that the genetic composition of Huseby Klev individuals show more similarity to western hunter-gatherer populations than eastern hunter-gatherers," said Emrah Kirdök at Stockholm University, who conducted the computational analyses of the DNA.

In their study, the researchers explained DNA from ancient chewing gums has enormous potential not only for tracing the origin and movement of people a long time ago but also for providing insights into their social relations, diseases, and food.

In a recent study published in Scientific Reports, scientists from Stockholm University elaborate on the results brought to light by a new analysis of chewing gum.

"To broaden our understanding of human health and everyday life in Mesolithic Scandinavia, we investigated the metagenomic content of three pieces of ancient pitch material from one site. Using this data, we explored oral microbiome composition, diet related DNA reads, and resource utilisation," the scientists state in the study.

Credit: Adobe Stock - Gorodenkoff

It is now known that about 9,700 years ago, a group of people was camping on the island of Orust north of what is today Göteborg (Gothenburg). These individuals had been fishing, hunting, and collecting resources for food. Among the teenagers were boys and girls who were chewing resin to produce glue, just after munching on trout and deer, as well as on hazelnuts. Due to a bad case of periodontitis (severe gum infection that can lead to tooth loss and bone loss), one of the teenagers had problems eating the chewy deer-meat and preparing the resin by chewing it.

"There is a richness of DNA sequences in the chewed mastic from Huseby-Klev, and in it we find both the bacteria that we know are related to periodontitis, and DNA from plants and animals that they had chewed before," Dr. Emrah Kırdök, from Mersin University Department of Biotechnology, who coordinated the metagenomic work on the Mesolithic chewing gum explained.

What Was The Stone Age Diet?

We found that the chewed pitch material is an excellent source of ancient DNA, which can be used to understand diet, raw material use, and oral health conditions in prehistoric and early modern populations. We reconstructed several ancient bacterial genomes and found notable amounts of oral pathogens. Furthermore, we compared the microbial profile in chewed pitch mastic particles to modern human salivary microbiomes. Our results show that the bacterial profile is similar to modern periodontitis cases.

The samples also contained eukaryotic species like hazelnut, trout, mallard, red fox, limpet, and red deer. These species provide sources for reconstructing Mesolithic diet and paleoenvironment, while the presence of many of the species identified in this study is supported by archaeological finds. These DNA data may provide clues to specific dietary items but do not represent the whole variety of food sources used during the Scandinavian Mesolithic. They do, however, indicate what members of this particular group had been orally processing before or during their interaction with the pitch.

The plastelina casts for one of the chewing gums from Huseby Klev. The cast captures the teeth imprints from each side. Credit: Verner Alexandersen

Our results portray a group of Mesolithic hunter-gatherers in south-western Scandinavia, where individuals likely suffered from dental diseases and were utilising resources from different domains through oral manipulation," the researchers write in the study.

The study "provides a snapshot of the life of a small group of hunter-gatherers on the Scandinavian west coast. I think it is amazing, there are other well established methods to work out what nutrition and diet relates to the Stone Age, but here we know that these teenagers were eating deer, trout, and hazelnuts 9 700 years ago on the west coast of Scandinavia, while at least one of them had severe problems with his teeth," Professor Anders Götherström, at the Centre for Palaeogenetics concluded.

Written by Conny Waters - AncientPages.com Staff Writer