Danish scientists have managed to extract and characterize a complete human genome from a piece of thousands-of-years old ‘chewing gum.’ This provided an unexpected and surprisingly source of ancient DNA, for the scientists at the University of Copenhagen to analyse.
The ancient gum was found during an exploration of the Danish Lolland (Syltholm, east of Rødbyhavn), which is a major Stone Age site of archaeological interest. The gum was a piece of birch pitch, commonly chewed by people of the time in order to help off-set tooth decay (the pitch has some mild antiseptic properties). Birch pitch is a black-brown substance formed by heating birch bark. As well as being chewed, the pitch was also used as a form of glue.
According to Professor Hannes Schroeder, who led the study, as well as retrieving the human genome of the person who had chewed the birch, the analysis also “retrieved DNA from oral microbes and several important human pathogens, which makes this a very valuable source of ancient DNA, especially for time periods where we have no human remains.”
The human genome analysis shows that the gum was chewed by a female, of the hunter-gatherers from the mainland Europe. The woman will have had, the genetic evidence reveals, dark skin, dark hair and blue eyes.
The genomic analysis even provides clues as to what the woman may have eaten, as traces of hazelnuts and duck were recovered from the chewed birch.
In terms of the microbial analysis, this revealed that the woman was infected with DNA that is very similar to today’s Epstein-Barr Virus. This virus causes infectious mononucleosis or glandular fever.
The research paves the way for other types of chewed materials, which may be present on the site or at others around the world, to be analysed with hope of revealing more about our ancient ancestors.
The research has been reported to the journal Nature Communications. The research study is titled “A 5700 year-old human genome and oral microbiome from chewed birch pitch.”
