The peer-reviewed study, published in the Biology Letters journal reveals how the natural mummification process can preserve DNA for much longer than it would be preserved under normal circumstances.
Whereas ancient DNA is usually damaged and fragmented, the sheep mummy's DNA was in a much better condition, with longer fragment lengths and less damage than it was expected to have, given its age.
This high-level of preservation was due to the Iranian salt mine, known as Chehrabad, from which the mummy was extracted.
The research carried out in this new study corroborated with a hypothesis first presented with the discovery of the Salt-men in 1993, wherein miners discovered the corpses of six men inside of the Chehrabad salt mine, all estimated to have died 1,700 years earlier. The men retained aspects of their original features, including skin and hair.
The salt of the Chehrabad mine works to naturally preserve corpses in a mummification process, as the salt absorbs the water from the corpse, preventing the soft tissues from breaking down and decaying.
The research team noted that the animal was genetically similar to modern sheep breeds from the same region, an indication that there has been a constant presence of the species in Iran for at least the last 1,600 years.
Conor Rossi, lead author of the paper and PhD candidate in Trinity's School of Genetics and Microbiology, commented on the research and the discovery of the DNA, saying that "the astounding integrity of the DNA was not like anything we had encountered from ancient bones and teeth before. This DNA preservation, coupled with the unique metagenomic profile, is an indication of how fundamental the environment is to tissue and DNA decay dynamics."
The team also built a genetic impression of the sheep, using the DNA to create an image of what the animal would have looked like while it was alive, and discovered that although it lacked the gene variant associated with the woolly coat, it did have hair fibre on its body consistent with several breeds of sheep still alive today.
Study supervisor Dr Kevin G Daly of Trinity's School of Genetics and Microbiology also commented on the outcome of the research, saying that "using cross-disciplinary approaches we can learn about what ancient cultures valued in animals, and this study shows us that the people of Sasanian-era Iran may have managed flocks of sheep specialized for meat consumption, suggesting well-developed husbandry practices.“