Syltholm - the Ancient Chewing Gum
Lola was a young Danish girl with bright blue eyes, dark skin, and inky hair. She lived in a small fishing village, and her last meal consisted of duck and hazelnuts, but because she was lactose intolerant, there was no trace of dairy. These facts could be considered standard details about many people, but, interestingly, Lola died approximately 5,700 years ago. So how do we know such specific information about her?
Astonishingly, these details are available to us because of a discarded piece of ancient chewing gum made from the bark of a birch tree. Lola may have chewed it to create glue for fixing a tool or perhaps purely for enjoyment. Regardless, when she was done with the tar, she tossed it aside, and it became lost under layers of earth for thousands of years until archaeologists uprooted it. To their delight, the gum held the genome, oral microbes, and even dietary facts about its chewer.
What was discovered at Syltholm?
Syltholm has revolutionized our concept of ancient humans due to finally providing a suitable sample for the analysis of ancient genomics. A stone-age sample of chewing gum, composed of birch tar and some other natural substances was found there - astoundingly well preserved and complete with clear dental indentations - after being hidden for thousands of years.
Heating birch bark was regular practice in prehistory Scandinavia to create a glue-like substance for forging tools, in particular, setting handles onto stone items. The substance was also commonly used as chewing gum, and similar to modern chewing gums, it had the capacity to survive for thousands of years in the right conditions.
Scientists have often pondered why these ancient populations so frequently chewed the birch bark. One possible reason was to soften it and make it malleable enough to use as glue; another reason was that the bark had mild antiseptic qualities so it may have been used to ease toothaches, or it might also have been used as a prehistoric toothbrush to clean teeth. Or perhaps the birch tar was chewed simply because it was enjoyable.
Whatever the reason for chewing it, scientists are grateful; the Syltholm sample has provided an insightful window into an ancient lifestyle and demonstrated the birch barks incredible ability to preserve DNA.
What the Syltholm sample tells us about Lola
Fortunately, the archaeologists who discovered the gum in Syltholme recognized its significance, as otherwise this valuable artifact might have been regarded as useless ancient discard. Although the lump of tar looks innocuous and unremarkable, what it facilitates is astounding. In the case of Lola, it was the first time that a complete prehistory genome was extracted from anything other than bones and teeth. Therefore, the 2cm long lump of chewing gum enabled scientists to conjure up a well-rounded and accurate image of her.
Although no human remains were found at the dig site at Syltholm where Lola lived, the chewing gum permitted archaeologists to determine what she looked like, as well as what her diet consisted of, and any viral or bacterial strains that she may have supported.
The era’s poor hygiene helped to provide extra information about Lola; her gum revealed evidence of hazelnut and mallard DNA, suggesting that she likely came from a community of hunter-gatherers. Furthermore, her extracted genome indicates that she is genetically more European in origin - specifically Belgium and Spain - than the farming populations from Scandinavia.
Lola’s chewing gum sample also provides us with precious information about her microbiome - a group of mostly harmless bacteria that occupy the human body. Even though a rich body of information about Lola’s microbial status was gathered from the gum, it was impossible to determine her state of health. However, it was clear that she carried the Epstein-Barr virus (which more than ninety percent of modern humans carry) and several pneumonia-associated pathogens.
The host of information that a sample of birch gum carries may depend on the environment in which it was buried. In the case of Lola’s piece, the reason why the gum carried so much information may be because it was stored in a relatively low oxygen environment; Syltholm was almost entirely sealed in mud, which ensured the preservation of the otherwise fragile organic material.
Conclusion
Seeing as it is often difficult to extract information from large periods of time due to a lack of tangible human remains, Syltholm opens many opportunities to derive rich and personal details about people from ancient eras - especially considering that the gum contains microbial DNA from the mouth. For this reason, the birch tar gum could be an even more invaluable source of information about long-lost communities than bones.
If you would like to find out more about how your DNA could be linked to ancient populations such as Lola’s, then you can find out through My True Ancestry.
