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Ancient “chewing gum” contains a 5,700-year-old genome, Ars Technica

Ancient “chewing gum” contains a 5,700-year-old genome, Ars Technica

      Genetics you can sink your teeth into –


The long-dead woman had blue eyes and dark skin, and she was lactose intolerant.




This artist’s reconstruction. shows “Lola” as a young girl, with items that likely would have been part of her daily life, but we have no way of knowing how old she was when she chewed and discarded the lump of birch-bark pitch. Tom Björklund 5,

years ago, a woman in what is now Denmark chewed a lump of birch-bark pitch for a while and then dropped it. Millennia later, the DNA she left behind reveals her entire genome, a census of the bacteria living in her mouth, and a few hints about a recent meal.

If you’re a hunter-gatherer who needs to haft a stone tool, birch-bark pitch makes a handy adhesive

, but you might have to chew it to make it pliable enough to work with. Pitch is watertight and contains an antiseptic compound called betulin, so it’s great at preserving DNA. In fact, archaeologists in Scandinavia have found more

human DNA in bits of chewed pitch

than they have in skeletons (which have been relatively rare at prehistoric Scandinavian sites we’ve studied thus far).

But this is the first time researchers have managed to sequence an ancient person’s whole genome from a lump of chewed pitch. Only about a third of the DNA bioarchaeologist Hannes Schroeder, of the University of Copenhagen, sampled was human; the other percent came from the ancient woman’s microbiome and traces of a prehistoric meal. This single discarded piece of ancient chewing gum tells us that the ancient woman, who Schroeder and his colleagues have nicknamed Lola, was probably lactose intolerant, ate duck and hazelnuts, and may recently have had pneumonia. She also had blue eyes, dark brown hair, and dark skin. “This combination of physical traits has been previously noted in other European hunter-gatherers, suggesting that this phenotype was widespread in Mesolithic Europe and that the adaptive spread of light skin pigmentation in European populations only occurred later in prehistory, ”wrote Schroeder and his colleagues.
She lived through the Neolithic revolution

The detail we can extract with DNA turns a seriously unprepossessing artifact into a deeply personal link to life in the past. It also sheds light on the much larger cultural upheaval that was reshaping Lola’s world. While Lola was eating hazelnuts at the prehistoric settlement now called Syltholm, people from southwest Asia were spreading westward across Europe, bringing a new way of life with them: farming.

Around the time Lola lived in Denmark, the hunter-gatherer culture called Erlebolle gave way to the Funnel Beaker culture, a way of life built on farming and livestock. From archaeological data, we know that cultural change happened very quickly in Denmark, with people’s settlement patterns and ways of making a living changing almost overnight. But what we don’t know is whether that’s because new people moved in, displacing the old Erlebolle hunter-gatherers, or if it’s because the people already living in Denmark adopted new ideas.

Lola’s genome suggests that she’s not related to the Neolithic farmers who swept westward. And that implies that the newcomers didn’t immediately replace or absorb the hunter-gatherers who had been living in Denmark since the end of the Ice Age. In Lola’s day, it seems that at least a few of the old hunter-gatherer groups were still around, even if they’d adopted new ways of life. That lines up well with other genomic evidence from elsewhere in Europe, but it’s important not to draw firm conclusions based on a single genome.

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