The whole human genome was successfully retrieved from "chewing gum" produced thousands of years ago by scientists at the University of Copenhagen. The scientists claim that it is a fresh, unexplored supply of ancient DNA.

The Danish Stone Age woman's private details were revealed by a 5,700-year-old lump of pitch tar, and "chewing gum" gives new light on the evolution of our species.

The DNA in a piece of well preserved Paleolithic chewing gum from an island famed for its mud allowed researchers to identify the skin, hair, and eye colors as well as the pathogen profile, dental health, nutrition, and other characteristics.

Her whole genome as well as the genomes of other species that lived in her mouth were collected by scientists on the spot. She was a carrier of the viral virus that many of us have today, was lactose intolerant, and appeared to prefer wild food over everyday grain goods.

The research's principal investigator, Associate Professor Hannes Schroeder of the Globe Institute, University of Copenhagen, said, "It is astounding to have recovered a whole ancient human genome from anything other than bone."

Furthermore, he continues, "we also recovered DNA from oral microorganisms and numerous significant human illnesses, making this a highly rich source of ancient DNA, especially for times where we do not have human remains."

Sealed in mud

The fact that this person, "Lola," was called after the island where the gum was discovered and had dark complexion suggests that northern Europeans' lighter skin evolved considerably later and was more adapted. She was able to chew birch bark gum for a variety of reasons.

Birch pitch has been used since the Paleolithic, according to historical records. The resin of different trees, which served as the principal Stone Age adhesive, becomes more malleable the more it is heated, and chewing may have been a method of keeping it malleable as it cools when heated. She might have chewed the gum because of its antibacterial capabilities to help with her toothache, or she might have done so because she likes the monotonous biting that many of us love when we chew gum these days.

The birch pitch was found during an archaeological dig in southern Denmark's Syltholm, which is east of Rdbyhavn.

“Syltholm is totally distinctive. The preservation of organic remains is really extraordinary because almost everything is sealed in mud”, according to Theis Jensen, a postdoc at the Globe Institute who worked on the topic for his Doctorate and also took part in the excavations at Syltholm.

The archaeological findings indicate that the site's inhabitants continued to heavily utilize wild resources far into the Neolithic, which is when farming and tamed animals were first introduced into southern Scandinavia. It is the largest Stone Age site in Denmark, he continues.

Lola lived in a time when farmers and hunters-gatherers coexisted in the same regions, which wasn't always thought to be likely. This argument is supported by her preference for mallard duck and hazelnuts while other Paleo-Danes consumed their crops, as well as by her intolerance to lactose, which is frequently observed in northern Europeans after domestication of animals.

The Villum Foundation and the EU's Horizon 2020 research initiative through the Marie Curie Actions funded the study.