The "chewing gum"
For the first time, researchers have extracted an entire ancient human genome from a sample other than bones, in a gum chewed by a 5,700-year-old female, unearthing details about the diet and oral microbes of stone age people. The researchers, including those from the University of Copenhagen in Denmark, extracted the complete ancient human genome from a sample of birch pitch -- a gummy substance derived from the distillation of the birch tree's bark.
Mainland Europe hunter-gatherers' relation
According to the study, published in the journal Nature Communications, the "chewing gum" was found during archaeological excavations at Syltholm in southern Denmark. Based on the analysis of the genome, the researchers could tell that the birch pitch was chewed by a female. "The individual who chewed the pitch was female and that she was genetically more closely related to western hunter-gatherers from mainland Europe than hunter-gatherers from central Scandinavia," the researchers wrote in the study.
Important findings from the gum
The archeologists also found that she probably had dark skin, dark hair, and blue eyes. Additionally, the scientists could also extract DNA of oral bacteria and infectious microbes from the pitch sample, proving that these kinds of gums can be a very valuable source of ancient DNA, especially for time periods which have no human remains.
Nature's preservation
According to the researchers, the environmental conditions at the site where the birch pitch was found contributed to preserving the sample. "Syltholm is completely unique. Almost everything is sealed in mud, which means that the preservation of organic remains is absolutely phenomenal," said a study co-author from the University of Copenhagen. The study noted that Stylholm is one of the biggest Stone Age sites in Denmark.