The Oldest Scandinavian Human DNA Is Revealed By Chewing Gums

There are few human bones of this age, close to 10,000 years old, in Scandinavia, and not all have preserved enough DNA for archaeogenetic studies. In fact, the DNA of these newly examined chewing gums is the oldest human DNA sequenced so far in this area. The DNA derived from three individuals, two women and one man, creates an exciting link between material culture and human genetics.

The old chewing gums are now an alternative source for human DNA and, possibly, a good substitute for human bones in archeogenetic studies. The pieces investigated come from Huseby-Klev, one of the first sites of the Mesolithic hunter-fisherman on the west coast of Sweden. The excavation of the sites was done in the early 1990s, but at this time it was not possible to analyze the ancient human DNA, much less the non-human tissue. The chews were made from birch bark tar and were used as glue in the production of tools and other types of technology during the Stone Age.

"When Per Persson and Mikael Maininen proposed to look for the DNA of the hunter-gatherer in these chewing gums of Huseby Klev, we were undecided but really impressed that the archaeologists took care of the excavations and preserved that fragile material," says Natalija Kashuba, who was affiliated a The Museum of Cultural History of Oslo when he carried out the experiments in cooperation with the University of Stockholm.

"It took some work before the results overwhelmed us, as we understood that we came across this almost 'forensic investigation', the DNA sequencing of these putty lumps, which were spit on the site about 10,000 years ago!" says Natalija Kashuba. Today Natalija is Ph.D. Student at the University of Uppsala.

Exciting link between material culture and human genetics.

The results show that, genetically, the individuals whose DNA was found share a close genetic affinity with other hunter-gatherers in Sweden and with the early Mesolithic populations of the Ice Age in Europe. However, the tools produced on the site were part of the lithic technology brought to Scandinavia from the Eastern European plain, now Russia. This scenario of culture and genetic influx in Scandinavia from two routes was proposed in previous studies, and these old gums provide an exciting link directly between the tools and materials used and human genetics.

Emrah Kirdök at the University of Stockholm conducted the computational analysis of DNA. "Demographic analysis suggests that the genetic makeup of Huseby Klev individuals shows more similarity to western hunter-gatherer populations than eastern hunter-gatherers," he says.

"The DNA of these old chewing gums has a huge potential not only to track the origin and movement of peoples a long time ago, but also to provide information about their social relationships, diseases and food," says Per Persson, of the Museum of Cultural History. in Oslo. "Much of our history is visible in the DNA we carry with us, so we try to look for DNA where we think we can find it," says Anders Götherström, from the Archaeological Research Laboratory at the University of Stockholm, where the work was done. The study is published in Communications Biology.

By: Preeti Narula

Content: https://www.sciencedaily.com/releases/2019/05/190515085450.htm