The DNA of a 5700-year-old woman who dined on hazelnuts and duck has been extracted from a piece of ancient chewing gum.
Researchers from the University of Copenhagen announced on Wednesday they had successfully extracted a complete human genome from a piece of chewed birch pitch - a form of dry heated bark - found at Syltholm on Lolland Island, Denmark.
It's the first time that an entire ancient human genome has been extracted from anything other than human bones, and based on the DNA, researchers believe it belonged to a female. She was likely a hunter-gatherer from mainland Europe with dark skin, dark hair and blue eyes.
Traces of plant and animal DNA - hazelnuts and duck, respectively - was also found, pointing to what the woman may have consumed.
In an artist's reconstruction of what the woman may have looked like, she is named Lola and is painted sitting next to a duck and river.
"It is amazing to have gotten a complete ancient human genome from anything other than bone," said Associate Professor Hannes Schroeder, who led the research.
"What is more, we 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."
Some of the DNA extracted was also connected to the Epstein-Barr virus, a form of herpes virus which can lead to glandular fever.
The piece of birch pitch was found during an excavation carried out during the construction of a tunnel.
"Almost everything is sealed in mud, which means that the preservation of organic remains is absolutely phenomenal," said Theis Jensen, who worked on the study.
"It is the biggest Stone Age site in Denmark and the archaeological finds suggest that the people who occupied the site were heavily exploiting wild resources well into the Neolithic, which is the period when farming and domesticated animals were first introduced into southern Scandinavia."
Birch pitch is often found with teeth imprints, suggesting it used to be commonly chewed. It may have also been used as a form of antiseptic or to help relieve toothache.
The study has been published in the scientific journal Nature Communications.
