Almost 6,000 years ago on the island of Lolland, Denmark, a young girl disposed of her chewing gum. Now, University of Copenhagen researchers have used that gum, made from birch pitch, to sequence the girl's full genome. From Science:
The child had black hair, blue eyes, and dark skin, and was more closely related to hunter-gatherers from Western Europe than to farmers who had more recently settled in the region. She left traces of her most recent meal in the gum—she had been chewing hazelnuts and duck. But her oral microbiome also revealed that life could be hard—she had the Epstein-Barr virus and probably had suffered from mononucleosis in her life.
More in the scientific paper: "A 5700 year-old human genome and oral microbiome from chewed birch pitch" (Nature Communications)