Amazing stuff! Gum and spit! Chewing gum has a long history!
"Long before duct tape or bubble gum, Stone Age farmers had all-purpose birch bark tar. Around 6000 years ago, they used it to ... glue broken pottery, haft stone blades, and even as chewing gum.
For the first time, researchers have now recovered DNA and other clues from spat-out lumps of the stuff and the tools and pottery they patched. The findings could reveal new insights into what prehistoric Europeans ate, their oral health, and even how they divvied up their chores.
Researchers examined 30 tar samples from nine sites, mostly lakeside settlements around the Alps. Although bones and teeth rarely survive in such wet environments, the waterlogged conditions were ideal for preserving organic material such as tar. Chewed pieces contained both male and female DNA. Some even appeared to have been chewed by multiple people. Interestingly, all four tar pieces used to haft stone tools carried male DNA, whereas all three of the tars used to repair pottery contained female DNA.
This discovery hints that birch tar could help researchers explore a question usually invisible in the archaeological record: how people divided work in prehistoric communities. The sample size is too small to confirm a gender divide between toolmaking and pottery repair just yet, but future work could explore this question further.
The chewed lumps also preserved traces of ancient saliva and mouth microbes. Notably, these microbes more closely resembled modern oral microbiomes than those found in dental calculus, suggesting birch tar may capture a different, previously unknown snapshot of oral health."
"... Birch bark tar is the world’s oldest known synthetic material. To make it, Stone Age people stewed bundles of the papery, peeling skin from birch trees over a fire until the natural resins oozed out into a black, gooey tar. Then, they used the sticky substance to haft stone blades to handles, mend cracked pottery, and even chew as a burnt-tasting gum to keep the tar pliable as they worked. ..."
From the abstract:
"Birch bark tar was widely used throughout prehistoric Europe for hafting stone tools as well as various other purposes. While previous research has mainly focused on the identification and production of birch bark tar, its diverse uses remain to be fully explored.
In this study, we combined ancient DNA with organic residue analysis to analyse 30 birch tar artefacts from nine Neolithic sites in and around the Alps. We identified birch tar as the main component, with some samples also containing conifer resin or tar, possibly added to modify its properties.
Degradation markers indicate that tar used for ceramic repair was heated repeatedly, probably during cooking.
Additionally, the presence of human and oral microbial DNA in some of the samples suggests the tar was chewed, in some cases by multiple individuals. The human DNA also enables us to determine the sex of those who chewed the tar, offering insights into gendered practices in the past, while plant and animal DNA shed light on past diets and the possible use of additives. This study underscores the value of integrating organic residue and ancient DNA analysis of archaeological artefacts to deepen our understanding of past cultural practices."
Ancient DNA and biomarkers from artefacts: insights into technology and cultural practices in Neolithic Europe (open access)
Figure 1. Sites and samples.
Figure 3. Ancient human DNA.
(A) Proportion of ancient human DNA reads post-deduplication in the three adhesive categories: lumps (n = 10), hafting (n = 6) and repair (n = 3).
(B) Sex determination results for ancient human DNA extracted from tar pieces (n = 12), tar used for hafting (n = 10) and repair/sealing (n = 8), determined using karyo_RxRy ...
Figure 6. Making and using birch tar in Neolithic Europe. A possible chaîne opératoire from the initial production of birch tar to the final use, including potential recycling of tar, and the biochemical analyses that can be used to investigate steps in this process.
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