In a groundbreaking study recently published in Nature Scientific Reports, researchers have achieved the remarkable feat of extracting ancient DNA from a nearly 3,000-year-old clay brick, shedding light on the flora of a long-gone era. This extraordinary brick, currently housed at the National Museum of Denmark, once formed part of the grand palace of the Neo-Assyrian king Ashurnasirpal II. It provides a fascinating glimpse into the past, revealing what plant life was like in the ancient city of Kalhu, modern-day northern Iraq, around 879 BCE.
The study, which was conducted as part of a digitization project at the museum in 2020, used a protocol adapted from techniques usually employed on porous materials such as bone to extract the DNA. This innovative approach has not only yielded information about 34 distinct plant species cultivated during the Neo-Assyrian period, but also presents exciting possibilities for future research. By using similar techniques, scientists could potentially unravel the botanical mysteries of other archaeological sites and eras, offering unprecedented insight into the biodiversity of our planet’s past.
Ancient DNA Uncovered from 2,900-year-old Clay Brick: Peering into the Plant Life of Assyrian Era
In an unprecedented study published in the journal Nature Scientific Reports, scientists have extracted ancient DNA from a 2,900-year-old clay brick, offering a glimpse into the plant life of that period. This groundbreaking research presents potential for similar studies on clay artifacts from diverse historical periods and geographical locations.
Tracing the History
The clay brick that was examined originates from the palace of the Neo-Assyrian king Ashurnasirpal II, situated in ancient city of Kalhu (modern-day Nimrud, northern Iraq). This brick, currently preserved in the National Museum of Denmark, carries a cuneiform inscription in the extinct Semitic language, Akkadian. The inscription reads, "The property of the palace of Ashurnasirpal, king of Assyria," allowing researchers to date the brick precisely to between 879 BCE to 869 BCE.
Unlocking the DNA
In 2020, as part of a digitization project aimed at minimizing DNA contamination, the DNA extraction process took place. The research team adapted a protocol, previously used for other porous materials like bone, to extract the DNA from the inner core of the brick. Sequencing of this DNA led to the identification of 34 distinct taxonomic groups of plants.
Unveiling the Plant Life
The most abundant sequences belonged to Brassicaceae (cabbage) and Ericaceae (heather) families. Other identified families included Betulaceae (birch), Lauraceae (laurels), Selineae (umbellifers), and Triticeae (cultivated grasses). The interdisciplinary research team, which included assyriologists, archaeologists, biologists, and geneticists, compared their findings with modern-day botanical records from Iraq and ancient Assyrian plant descriptions.
The Making of the Brick
The clay brick was primarily made of mud collected from the nearby Tigris river, mixed with materials like chaff, straw, or animal dung. After shaping the mixture in a mold and inscribing it with cuneiform script, the brick was left to dry naturally in the sun. The absence of burning in the brick-making process facilitated the preservation of genetic material within the clay.
Implications and Potential
The research not only provides insight into the biodiversity of a specific period but also serves as a proof of concept that can be applied to various archaeological clay sources worldwide. While this study focused on plant DNA, the potential to identify all taxa, including vertebrates and invertebrates, is a promising step towards accurately describing ancient biodiversity, enhancing our understanding of ancient civilizations and present-day biodiversity loss.
This pioneering research highlights the potential of interdisciplinary collaboration in science and the value of ancient artifacts in unraveling our past. As we continue to lose biodiversity at an alarming rate, studies like these offer a valuable tool to quantify and understand the extent of this loss. Furthermore, the method used in this study opens a new avenue for archaeological research, offering a chance to explore the biodiversity of different eras and regions across the globe. The clay bricks, like the one used in this study, become time-capsules, giving us a unique access to the past and helping us understand our present better.