Parchment documents--ancient writings on animal skins--record an immense wealth of information about the history of humanity and past civilizations. However, new research has shown that within these ancient texts lies another hidden source of knowledge – the DNA preserved in the animal skins used to make the parchment.

The main species used for documents recorded on animal skins, which dates back to around 2,500 BC in Egypt, were young or fetal cattle, sheep and goats. Parchment was used for writing mercantile, legal, scholarly, religious, philosophical and historical documents.

Aside from their human historical value, DNA in parchments may help scientists understand the genetic history of domesticated farm animals. Scientists from the University of York in England and Trinity College in Ireland hope to use DNA from parchments to study the history of agriculture in the British Isles over the past 1,000 years.

As a pilot study, they extracted DNA samples from two sheepskin documents in Britain – one from the 17 th century, the other from the 18 th century. Daniel Bradley, a professor of Population Genetics Trinity College Dublin told the university’s news service : “This pilot project suggests that parchments are an amazing resource for genetic studies that consider agricultural development over the centuries. There must be millions stored away in libraries, archives, solicitors’ offices and even in our own attics. After all, parchment was the writing material of choice for thousands of years, going back to the Dead Sea Scrolls (5 th – 4 th century BC).

Ancient documents as old as the Dead Sea Scrolls (pictured), were written on parchments ( Wikimedia Commons )

“Wool was essentially the oil of times gone by, so knowing how human change affected the genetics of sheep through the ages can tell us a huge amount about how agricultural practices evolved.”

The DNA extracted from these parchments revealed that the 17 th century sample came from sheep from Northern Britain, where there were Swaledale, Rough Fell and Scottish Blackface sheep. The second DNA sample showed a closer connection to the Midlands and southern Britain, where livestock improvements were underway in the 18 th century.

Central European type of finished parchment made of goatskin stretched on a wooden frame ( Wikimedia Commons )

Professor Matthew Collins, head of the University of York’s Department of Archaeology’s BioArCh research center, said: “We believe the two specimens derive from an unimproved northern hill-sheep typical in Yorkshire in the 17th century, and from a sheep derived from the ‘improved’ flocks, such as those bred in the Midlands by Robert Bakewell, which were spreading through England in the 18th century. We want to understand the history of agriculture in these islands over the last 1,000 years and, with this breath-taking resource, we can.”

Writing in The Royal Society Publishing , the researchers estimated there could be 4 million or more ancient parchments in Britain alone because the primary method of inscribing was on parchment until paper replaced parchment in the later Middle Ages, around the 15 th century. Many parchment documents were protected from heat and moisture damage in the 20 th century.

“Indeed, the number of skins is truly staggering, even if, as is likely, a high percentage of documents have been destroyed. In the UK alone, assuming the number of sheep slaughtered annually remained constant at 15 million from 1150 to 1850, then if only 1% of all the skins became parchment and only 4% survived, this would equate to 4.2 million animals' skins,” the researchers wrote . They say it is hard to estimate the number but believe more than 1 million survive.

Parchments can be dated fairly precisely using modern methods, which is valuable in assessing the genetic changes in animals through time.

Featured image: Millions of ancient books and documents were written on parchment. The DNA preserved within them may reveal new information about agriculture through history. ( Wikimedia Commons )

By Mark Miller