A 5,700-year-old chewing gum revealed a woman’s DNA microbes and possible last meal

A tiny bit of chewed birch pitch found in the southern part of Denmark can fundamentally alter how scientists consider what objects could be preserved. It was 5,700 years old. However, it was able to preserve much more than just the ancient tooth markings.Based on a study released by the scientific journal Nature Communications, this one object contained an entire human genome from the past and DNA from the oral microbes from the person who chewed it, as well as trace evidence of animal and plant life, probably from a dinner. This complex mix creates a unique object in its small size, which is why old, discarded chews matter equally to teeth or bones when it comes to DNA analysis in ancient DNA. This time, the object wasn't only a food trace or an instrument's remnant; it turned into a full document of a person's biological history, including who she was, what microbes lived in her mouth and what she may have recently eaten.A snack that turned into an important time capsuleThe main find originates from Syltholm in the southern part of Denmark. Archaeologists discovered the remains of a Birch pitch and identified it as a chewed piece that was found in the early Late Mesolithic or Early Neolithic transition phase. The process of making pitch from birch is melting birch bark and turning it into the dark and sticky material, which was probably chewed in order to soften it to use for hafting or attaching stone tools to wooden handles.In a research article published in PubMed Central, earlier research into old mastics has already revealed that birch bark pitch was an extremely useful, well-informed substance. The thing that makes this object amazing is its dense, sticky, resinous composition. It helped to protect delicate biomolecules when it was discarded and used up, acting like an enclosed archive. This physical environment is the reason the amount of material that survived was such a tiny fragment, which proves the quality of preservation depends on the characteristics of the substance itself, instead of only the conditions of the soil in which it was dug. A woman from the Stone Age comes into viewHuman DNA extracted from inside the pitch was powerful enough to construct a complete old genome. It is reported in the Nature Communications study that the woman was female and was part of a group that was closely connected to hunter-gatherers of the western region, who came from mainland Europe and not hunters from central Scandinavia.The DNA sequence from the past also helped researchers to identify her possible physical features. She is described as having dark skin tone, dark brown hair and blue eyes. The specific biographical details transform the prehistoric fragment from an unknown source into a real person sporting an identifiable human face. The pitch wasn't just kept track of where she was in old migration patterns; it also provided clues as to the way she looked, which provides a depth of intimacy in objects that can easily fit in the palm of one's hand.Human DNA was more than preservedThe pitch of the past did not just preserve host DNA. Researchers also discovered the microbial DNA that is consistent with a human oral microbiome that includes different taxa from bacterial and viral. It is believed that the device recorded a photograph of the user's mouth at precisely the time she was chewing and provides evidence that old oral biomaterials are able to help determine sex, ancestral origins, facial physical appearance, as well as the presence of disease-related signs.The most notable additional sign was the food DNA. Researchers found distinctive animal and plant fragments within the pitch that could be the remnants of a meal that was consumed before eating. This study shows that one object could preserve both the dish and what it was that they ate. This can help archaeologists understand human behaviour, subsistence, time, and the context in which they were making tools.In the end, the Danish discovery has firmly established the chewed birch pitch to be an important source for biomolecular archaeology based on artefacts. The discovery pushes the boundaries of archaeology beyond the traditional bones and opens up an avenue to objects which were previously viewed as merely debris; however, they now have rich, historical information.