Researchers successfully extracted 2,900-year-old DNA
A group of researchers has successfully extracted DNA from an ancient cuneiform brick for the first time, identifying over thirty species of plants present in the brick’s clay. This project—published in the journal Scientific Reports—provides fascinating insight into the natural environment at the time and place the brick was made, and also opens the way for similar studies to be carried out on clay objects from around the world.
The cuneiform brick used in the study can be dated to within the narrow timeframe of 879–869 BCE, based on its inscription, which marks it as a brick used in the construction of Ashurnasirpal II’s palace at Kalhu (modern Nimrud, Iraq). At the time, the city was the capital of the young Neo-Assyrian Empire (c. 883–612 BCE).
Likely made of mud collected near the Tigris River, along with other materials such as chaff, straw, or dung, the brick serves in effect as a time capsule recording the botanical environment surrounding its creation. Through analysis of the ancient DNA of the materials still preserved in the brick, the team was able to identify 34 separate plant species including cabbage, heather, birch, laurels, umbellifers (a family that includes parsley, carrots, and other flowering plants), and cultivated grasses. “We were absolutely thrilled to discover that ancient DNA, effectively protected from contamination inside a mass of clay, can successfully be extracted from a 2,900-year-old brick,” said Sophia Lund Rasmussen, one of the lead authors of the project.
The DNA sample was obtained from the brick after it was accidentally broken during routine handling at the National Museum of Denmark, where it is stored. While this would normally be an unfortunate occurrence, it allowed the team an exceptional opportunity to gather samples from the inside of the brick, where there was the least chance for contamination or degradation.
Although the botanical remains found within the brick were not particularly surprising, the project serves as proof of concept for future archaeological investigations into ancient DNA. Mudbricks of various sorts are some of the most abundant building materials throughout the ancient Near East. This new method provides archaeologists with a completely new way of exploring the ancient environment, both floral and faunal.
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