What a 5,700-Year-Old Piece of Gum Reveals About Its Chewer

This is further bolstered by the duck and hazelnut DNA the researchers found in the birch pitch, which are staple foods in that hunter-gatherer diet. But it’s also possible that those hazelnut genes came from hazelnut bark she mixed in with the birch when she made the pitch. And just because she may have been noshing on duck before she chewed the birch pitch, doesn’t mean she wasn’t eating cultivated crops too.

“There’s actually nothing to tell us that on a Thursday she didn’t do farming, and was eating duck on the weekend,” says Schroeder. “But what we can go on is that we know genetically, she looks like a Western hunter-gatherer.” That and where she was chewing pitch was likely a seaside marshland, not the greatest of places to homestead.

One more fascinating bit of evidence to suggest she wasn’t a farmer: her genes indicate lactose intolerance. The ability to digest milk in adulthood without severe gastrointestinal distress (babies, of course, need to be able to process milk) only came with the arrival of farming.

So here we have what was clearly a hunter-gatherer, exploiting natural resources as the world around her converted to agriculture. You see, the transition from the hunter-gatherer lifestyle to sedentary lifestyle was a stepwise process, not a sudden transformation of the whole of Europe into an industrialized food economy. “However, this transition is still not well known and it is being consistently studied,” says Emrah Kırdök, a paleogeneticist at Mersin University, who wasn’t involved in this work. “So according to our knowledge, farming was introduced to different parts of the world progressively, and some cultures could have remained as a hunter-gatherer society for some time.” Our gum chewer was one such holdout.

Now, about that mouth microbiome. Here we have the tricky matter of bacteria and viruses drifting all over a given environment, so some of the microbes could have landed on the pitch after she spit it out. Luckily, scientists have built a database of known species compositions of microbiomes around the body, including gut, skin, and mouth. The pitch-chewer, these researchers found, had an oral microbiome not all that different from our own. They even found standouts types, like the bacteria Streptococcus pneumoniae, which can lead to pneumonia, and Epstein-Barr virus, a variety of herpes and one of the more common human viruses. Same woes, different millennium, it seems.

Also intriguing is the woman’s phenotype, or physical characteristics, as suggested by her genome. In recent history, the European north has been populated by a lot of folks with lighter hair and skin and blue eyes—the idea being that from an evolutionary perspective, fairer skin would help humans in colder, darker climes manufacture enough vitamin D, whereas in hotter climes peoples would need more dark melanin to protect them from the sun. But while this woman had blue eyes, her genes suggest she had darker hair and skin. “That means that this combination of phenotypic traits was probably fairly common until recently,” says Schroeder. “That’s only really evolved in Europe in the last 5,000 years, which is interesting.”

So a tiny piece of chewed-up pitch reveals not only a heap of information about this ancient woman, but also adds a layer to the larger story of human evolution. Something to chew on, for sure.

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