An international team of scientists has successfully sequenced ancient DNA extracted from a 5,700-year-old piece of chewed birch pitch from southern Denmark. In addition to an ancient human genome and mitochondrial DNA (mtDNA), the researchers recovered plant and animal DNA, as well as microbial DNA from several oral species. Further analysis of the human DNA revealed that the individual whose genome the team recovered was female and that she likely had dark skin, dark brown hair and blue eyes.
Birch pitch is a black-brown substance obtained by heating birch bark. Small lumps of this organic material are commonly found at Scandinavian archaeological sites, and while their use is still debated, they often show tooth imprints, indicating that they were chewed.
The chewed piece of birch pitch analyzed in the current study was recovered from the Late Mesolithic/Early Neolithic site of Syltholm on the island of Lolland, southern Denmark.
“Syltholm is completely unique. Almost everything is sealed in mud, which means that the preservation of organic remains is absolutely phenomenal,” said lead author Dr. Theis Jensen, a postdoctoral researcher in the Globe Institute at the University of Copenhagen and the Department of Archaeology at the University of York.