Old Books' DNA May Reveal When, Where They Were Made

Rebecca Carroll
for National Geographic News

January 13, 2009

The animal-skin pages used in early medieval manuscripts contain genetic material capable of solving long-standing mysteries about the works, according to new research.

Before paper was widely used, European books were written on parchment made from the treated skins of calves, young sheep, and goats.

"What I was looking for was a way to date and localize these manuscripts," said Timothy Stinson, an English professor at North Carolina State University.

"In the past, we used an analysis of handwriting and an analysis of the dialects" of the scribes who created the manuscripts, Stinson said.

"But these were fairly inexact," he said, noting that dates determined by this method could be off by a half-century.

Stinson wondered if the pages held enough intact animal DNA to provide useful information, so he called his brother, C. Michael Stinson, a biologist at Southside Virginia Community College.

After several years of testing, Timothy Stinson will present the brothers' preliminary findings next week at the annual meeting of the Bibliographical Society of America in New York City.

(Related: "Ancient Texts as 'Fossils': How They Survive" [February 28, 2005].)

Below the Surface

Other medieval historians and literature scholars have wondered if viable DNA could be found in parchment, but specialists in the humanities don't often have ready access to biology expertise, Timothy Stinson explained.

"For me, it occurred to me, and I had someone to ask right away," he said, referring to his brother. "He actually knew what to do and what labs to send [the manuscripts] to for testing."

Rather than risking damage to a museum's manuscripts, the Stinsons bought their own collection of parchment leaves from a 15th-century French work.

They knew that centuries of human handling and animal contact had likely contaminated the surface.

"I've heard of people trying to swab parchment to get the DNA, and it turns out to be mouse DNA," Timothy Stinson said.

So the Stinsons cut sections out of the margins of their pages and sent them to a Canadian lab that specializes in the extraction of ancient DNA.

Since contamination is most likely to be on the surface, cutting the paper gave scientists access to unsullied center layers.

"Now we have to develop a technique that gets the same result without harming the manuscript," Timothy Stinson said. "We're going to try to repeat the experiments with increasingly less invasive tests."

Whole Herd

Because they wanted the first rounds of testing to have a better chance of success, the brothers targeted mitochondrial DNA.

This genetic material is passed down from mothers and is abundant in each cell, making it easier to obtain. But it provides less genetic information than nuclear DNA, which occurs only once in each cell.

The results gave the Stinsons reason to believe the five leaves they examined came from two animals—or perhaps more that were very closely related.

"In one book you could have a hundred or more animals," Timothy Stinson said. "You could have a whole herd."

Timothy Stinson wants to collect genetic information from as many manuscripts as possible to create a databank that could help scholars identify books created with the skins of related animals.

Because the date and location of some manuscripts are already known, such a network could help pinpoint the date and origin of other medieval books.

This type of information would additionally provide insight into the medieval parchment trade, and it could resolve debates about particular works and even written references within them.

New Leaves

Sayeed Choudhury heads the digital libraries at Johns Hopkins University in Baltimore, Maryland, which provided the seed funding for the Stinsons' first DNA tests in 2007.

Choudhury described the research as potentially groundbreaking.

"When someone looks at a manuscript, they don't usually think of it as data—they look at it as a physical document, which obviously it is," Choudhury said.

But "you can analyze it in a way that scientists and engineers analyze data," he noted.

"You can start to track the movement of these manuscripts over time," he added, likening the work to that of an epidemiologist who tracks the spread of disease.

"Tim has really shown us that you can look at humanities materials in layers," Choudhury said. "It's not just the reading and the viewing of manuscripts, but what's underneath it."

The Stinsons are now seeking funding for further DNA tests—which cost up to $1,000 (U.S.) each—to investigate nuclear DNA.