The York Gospels were assembled more than a thousand years ago. Bound in leather, illustrated, and illuminated, the book contains the four gospels of the Bible as well as land records and oaths taken by clergymen who read, rubbed, and kissed its pages over centuries. The Archbishops of York still swear their oaths on this book.
The York Gospels are also, quite literally, a bunch of old cow and sheep skins. Skin has DNA, and DNA has its own story to tell.
A group of archaeologists and geneticists in the United Kingdom have now analyzed the remarkably rich DNA reservoir of the York Gospels. They found DNA from humans who swore oaths on its pages and from bacteria likely originating on the hands and mouths of those humans. Best of all though, they found 1,000-year-old DNA from the cows and sheep whose skin became the parchment on which the book is written.
Remarkably, the authors say they extracted all this DNA without destroying even a tiny piece of parchment. All they needed were the crumbs from rubbing the book with erasers, which conservationists routinely use to clean manuscripts. The authors report their findings in a preprint that, as of this article’s publication, has not yet been peer-reviewed, though they plan to submit it to a scientific journal.
If their technique works, it could revolutionize the use of parchment to study history. Every one of these books is a herd of animals. Using DNA, researchers might track how a disease changed the makeup of a herd or how the skin of sheep from one region moved to another medieval trade routes. Itâ€™s part of a growing movement to bring together scholars in the sciences and humanities to study medieval manuscripts.
Scientists have extracted DNA from parchment before, but this non-destructive technique expands the potential pool of research material. Archivists are loathe to allow researchers to cut off a piece of, say, the York Gospels, but some eraser crumbs? Sure. â€œThatâ€™s why itâ€™s such an exciting breakthrough. It allows a lot of different manuscripts from a lot of different areas to be analyzed together,â€ says Bruce Holsinger, an English professor at the University of Virginia who is writing a book about parchment.
The idea to study parchment came to Matthew Collins, an archaeologist at the University of York, after a failed study in bones. A few years ago, he had a graduate student trying to extract ancient DNA from animal bones at an old Viking settlement. There were thousands of bones on the site, but only six that they tested yielded DNAâ€”too few for any statistically significant results. â€œYou can imagine the frustration,â€ says Collins.
So Collins got to thinking about archives full of old manuscripts. â€œYou look at these shelves, and every one of them has a skin of an animal with a date written on it,â€ he says. Suddenly you have thousands of animals. And you didnâ€™t even need to go out into the field and dig.