Using DNA fingerprints to explore the Dead Sea Scrolls

The discovery in 1946 of the Dead Sea Scrolls in a series of caves in the Judean Desert of the West Bank represented one of the most important archaeological discoveries ever made.

The 2,000-year old set of about 1,000 manuscripts includes the oldest copy of the Hebrew Bible—the Old Testament to Christians—as well as sectarian manuscripts which shed light on the rules and beliefs of Jewish groups. Written on papyrus or animal skins, they were created over the course of about 200 years and apparently hidden in the caves as a Roman army advanced on the area. The Dead Sea is one of the lowest places on Earth, and the dry desert climate helped preserve the materials.

The scrolls were hidden in 11 caves and uncovered in fragments, meaning that piecing them together, and clearly understanding what they tell, has been difficult. Some of those fragments are tiny and contain just a few letters; in all there are some 25,000 fragments.

Now, researchers at Tel Aviv University are lifting “DNA fingerprints” from the animal skins to learn more about the texts, and the results are helping to shed light on these ancient mysteries.

“Most of them were not found intact but rather disintegrated into thousands of fragments, which had to be sorted and pieced together, with no prior knowledge on how many pieces have been lost forever, or—in the case of non-biblical compositions—how the original text should read,” said Tel Aviv University researcher Oded Rechavi. “Depending on the classification of each fragment, the interpretation of any given text could change dramatically.”

The results of Rechavi’s work were recently published in Cell. In the Summary, researchers wrote that “'Piecing together’ scroll fragments is like solving jigsaw puzzles with an unknown number of missing parts.”

In this project, researchers extracted ancient DNA from the animals whose skins were used to create the scrolls were written on, then obtained DNA samples from 26 Dead Sea Scroll fragments and DNA samples from objects found alongside the scrolls in the caves. They later used a forensic analysis to demonstrate the genetic relationships between the different scroll fragments.

“The DNA sequences revealed that the parchments were mostly made from sheep, and some from cow,” noted Science Focus. “They reasoned that pieces made from the skin of the same animal must be related, and that scrolls from closely related animals were more likely to fit together than those from more genetically different animals.”

The most definitive findings came from the scrolls made from sheep skin. Here, researchers examined haplogroups from 126 sheep breeds. The work was precise enough, noted National Geographic, that researchers were able to distinguish different sheep flocks.

Among the discoveries was that some parts of book of Jeremiah came from both a sheep and a cow, which suggests that they don’t belong together. Another was that a work known as the Songs of the Sabbath Sacrifice were significantly genetically different, and that the work was likely more widespread than originally thought.

Further complicating matters is the finding that Judea was not a great place for cow husbandry 2,000 years ago, and there is no evidence of cow skin processing in the area, suggesting that some scroll fragments came from another part of the country, and that is corroborated by a finding that one fragment dates to the late third or early second century BCE, long before it was hidden in the caves.

Two fragments were found to be different from all the other fragments and likely are unrelated to the scrolls found in the caves—although authentic, they probably came from other caves in the area.

Researchers said they hope this work will inspire others to pursue similar projects.

“Such an integrative approach could be applied to analyses of many additional scrolls and diverse manuscripts,” they wrote. “We are hopeful that it will encourage others to collaborate and combine their expertise to solve the mysteries of the past.”