Kashuba et al 2019

Yup, old chewing gum is gross. However, when it is 10,000-years-old chewing gum it may also have something to teach us. Recently, gum that was first chewed between 9,450 and 9,880 years ago was found on the West Coast of Sweeden in a stone age hunter-gatherer archeological site called Husby-Kiev. When they analyzed the DNA that was found in the gum they learned a lot about what it was like for the ancient people who lived there.

What Exactly Is Ancient Chewing Gum?

It is pretty clear that ten millennia ago, ancient humans couldn’t unwrap their favorite flavor of Hubba Bubba or Trident and pop it into their mouth. They also weren’t that likely to chew on something for the simple pleasure of it, as we would. What researchers actually identified was a sticky birch bark tar that humans likely chewed and then used as an adhesive for tools or weapons.

Extracting DNA

Amazingly, the gum contained enough ancient saliva that scientists were able to extract some of the oldest DNA ever sequenced from archeological sites in the region. This was a fortunate and unexpected occurrence. It was also the only chance that scientists have had to extract DNA from Husby-Kiev. Despite the fact that the dig site had numerous artifacts, the human remains usually used for ancient DNA, such as bones and teeth, had degraded over time. The tar substance was scientists last hope at accessing information.

What was the process used? Once experts had the saliva in the lab, they sequenced entire genomes from the samples, identifying three different individuals in the process. Next, they compared the sequences with contemporary genomes from sites spanning both Eastern and Western Europe. Ten samples were used for comparisons to the initial three.

What Scientists Learned

Scientists learned quite a bit about what daily life was like during that time. Based on the DNA analysis, scientists verified that both men and women were involved in tool production at Husby-Kiev, not just men as was previously thought. In fact, two of the three individuals who were identified from the resin were female.  Scientists also found evidence, based on the fact that baby teeth markings were present, that children may have contributed in some way to making the tools. When the findings are looked at as a whole, they paint a picture of, perhaps, a family of toolmakers working together.

Once they were analyzed, the genetics identified through the samples told scientists a lot about the heritage of the early humans who lived in the area. While saliva sampling revealed a Western European biological lineage among the tool makers who had chewed the gum, types of tools in the area reflected an Eastern European influence. It is possible that the area maintained more of a cross-cultural feeling that reflected influences from multiple sources.

Thirdly, the resin itself also had something to teach experts. Scientists noted that it was made from birch rather than pine trees. This gave experts an image of these prehistoric humans at Husby-Kiev living in a birchwood forest similar to modern Scotland.

Not The First Surprising Place To Find DNA

With improvements in how scientists are learning to work with DNA, they’re able to access it in new and interesting places. As a result, archeological sites like Huseby-Kiev which were thought to have revealed everything possible, are beginning to provide even more information for experts to study. One example of this is in Maryland where the stem of a clay pipe provided the DNA of an enslaved woman who archeologists were learning about. Let’s hope that this process continues to provide new information. If so, unexpected sources of DNA could become an archeologist’s best partner.