Be careful of where you are spitting your chewed gum. 10,000 years later, it could end up as DNA evidence for the Homo Sapiens species.
No, that wasn't just an errant thought. A chewing gum spat out by a an ancient human 10,000 years ago is providing DNA evidence of the first humans ever to inhabit Scandinavia. The chewing gum, made of birch bark, is a masticated lump that was discovered in an early Mesolithic hunter-fisher site called Huseby-Klev, located on the west coast of Sweden in the 1990s.
Though bones of humans that settled in the Scandiavian region - which later came to cover the kingdoms of present-day Sweden, Denmark and Norway - were found during early excavations, they had degraded in quality, making it hard to sequence the DNa they contained. Thus the study of bones was not enough to chalk out a word-picture of early Scandinavian people.
However, chewed gum on the other hand can easily be studied for genetic footprints of our early ancestors as the masticated lumps retain saliva. When the Scandinavian pieces of gum were found in the 90s, no technology existed that could detect and study the DNA the objects contained. Researchers were still struggling to extract DNA from human-tissue remains, let alone inanimate objects.
However, recent studies conducted by Stockholm University researchers and published in Communications Biology, prove that gum could, in fact, be studied as hard genetic and anthropological research.
As per the researchers, the birch bark tar was used an adhesive to produce various tools in use at the time. Why is the discovery of DNA evidence important? According to the researchers, the discovery could shed information on the movement patterns of early humans and also their cultural ties, social relations and structures, diseases and food.
Researchers were able to differentiate three separate persons' DNA from the chewed up bits of gum - one of them male and two of them female. Since these gums were used for tool production, the discovery indicates that both women and men were involved in production. In fact, discovery of markings of milk teeth on the remains also indicate the involvement of children.
The discovery also sheds light on an important fact that both Scandinavian humans and hunter-gatherer human populations in Sweden show similar DNA. Additionally, the DNA matches that of early Mesolithic populations from Ice Age Europe.
Study of the tools previously found in the region suggested Eastern influences as the tools bore marks of Lithic technology. These influences probably reached Scandinavia from the East European Plain, the region that makes up present-day Russia. However, the genetic match to Western Europeans could mean the humans living in the region enjoyed contact with both Western Europe and present-day Russia.
So the next time you step on gum, don't be so mad. Maybe take a hard look at it and reflect on the long, long road we have taken to get here. One littered with pre-historic trash and ancient chewing gum.