Complete Human Genome Extracted from Ancient "Chewing Gum"
takyon writes:
What Ancient 'Chewing Gum' Can Tell Us About Life 5,700 Years Ago
The dark little blob would be easy to overlook at an archaeological site. Hannes Schroeder, a paleogeneticist at the University of Copenhagen, says a student brought it to him from a Stone Age site in Denmark and had a question: "Can we get DNA out of this?" Schroeder remembers replying: "We don't know, haven't really tried, so let's give it a go."
The researchers think ancient people chewed the black-brown substance, known as birch pitch, which "was obtained by heating birch bark," Schroeder says. He says it's not clear why they chewed the pitch, but it was likely to soften it up before using it as a kind of glue to stick sharp points onto weapons or tools. They may have even used it for medicinal purposes, such as a pain remedy for toothaches, because it is a mild antiseptic.
These were clues that the bit of "chewing gum" might contain human DNA, but the researchers expected it to be difficult to sequence it. After all, "it's still quite challenging to get a complete ancient human genome from human remains," Schroeder says.
But the DNA sequencing went better than anyone could have expected. The researchers were able to reconstruct a complete human genome. Schroeder says this is the first time that an entire ancient human genome has been extracted from anything other than human bones or teeth. The team published its findings in the journal Nature Communications [open, DOI: 10.1038/s41467-019-13549-9] [DX].
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