YSM Issue 96.3

FEATURE
Archaeology
THE BRICK OF LIFE
Ancient DNA Reveals Hidden Secrets
in a 2900-year-old Clay Brick
BY ILORA ROY
ART BY MIRANDA SELIN
Imagine walking down an old pathway, strewn with weathered
stones, when you trip on a loose brick. You might be irritated,
but what if those mundane little bricks were more than an
annoyance? What if they hid the secrets of civilizations from
thousands of years ago?
During a series of excavations beginning in 1949 led by Max
Mallowan and other British archeologists, a clay brick was
excavated from the ancient city of Kalhu in Mesopotamia, today
known as Nimrud, Iraq. The brick dates back 2,900 years to 879
B.C., which was during the reign of King Ashurnasirpal II over
the Neo-Assyrian Empire from 883 B.C. to 859 B.C. The Neo-
Assyrian empire was remarkable for many reasons, including
advancements in astronomy and mathematics, as well as
impressive architecture. The excavated “brick of life” was once
part of King Ashrunasipal’s palace. It is a sundried concoction
of straw, animal dung, and mud from the Tigris River, with an
Akkadian inscription on it that reads: “the property of the palace
of Ashurnasirpal, king of Assyria.”
The unassuming brick, which had broken horizontally into two
pieces, was then donated to the National Museum of Denmark
in 1958. Later, a group of scientists digitized it, splitting the
brick again, but this time vertically. However, this split wasn’t
troublesome—in fact, it was quite the opposite, as it allowed
researchers to study uncontaminated material inside the brick.
In an interview with Troels Pank Arbøll, Assistant Professor of
Assyriology at the University of Copenhagen and a key figure
in the project, he conveyed optimism and enthusiasm for the
potential discoveries on the horizon. The brick is a portal to a
bygone era that invites us to peer into the archives of history.
The researchers took five separate samples from the cracks
in the clay and analyzed them to produce the aDNA—ancient
DNA—of thirty-four taxonomic groups of plants. Each crack
offered a look into the past. This was done through two cuttingedge
sequencing techniques—a process in molecular biology that
involves determining the precise order of the building blocks
of DNA molecules. The first technique is amplicon sequencing,
which selectively amplifies and sequences specific DNA regions
within a larger genetic sample. The second is metagenomic
shotgun sequencing, which enables the exploration of all genes
across all organisms within a complex sample. These precise and
critical sequencing techniques were vital tools in uncovering the
truths behind the fragile aDNA, which is highly degraded due
to its age. The pursuit of these invaluable insights demanded
patience and unwavering commitment.
Scientists are certain that the DNA is uncontaminated since all
of the samples came from the core of the brick, which has not
been exposed to the outside world since the brick was first created
roughly 2900 years ago. Such certainty is remarkable, as it is rare
for aDNA so old to remain untouched. The species found in the
clay brick include specimens correlated with different types of
Iraqi flora, carrots, parsnips, celery, birch, and more. This aDNA
has bridged gaps in our understanding of the Neo-Assyrian
Empire, serving as a portal into the past.
The brick’s aDNA can also help us to look into the future.
By studying the species in such bricks, researchers may notice
differences and similarities between plants from 2900 years
ago and today. These observations will be important to combat
climate change and help our ecosystem because the past
furnishes researchers with invaluable insights into patterns of
biodiversity loss, teaching us how to mitigate similar perils in
the present day. “The goal would be, in due time, to establish
a dataset of historical biodiversity for reference in current
discussions,” Abrøll said. Examining how ecosystems responded
and adapted in the past can shed light on their resilience and
capacity for recovery in the future.
Beyond advancing our understanding of the ecosystem and our
history, this discovery shows the necessity of interdisciplinary
collaboration. When discussing the possible future for research
around endemic plants in Iraq, Arbøll emphasizes the importance
of collaborating with scientists when researching the history of
these plants. “It is our hope that future studies with more concrete
identifications of ancient DNA might help speed this process up,”
Arbøll said.
So, the next time you encounter a tricky loose brick, consider
the possibility that it might harbor a treasure trove of secrets,
bridging the chasm between antiquity and modernity—a
testament to the unyielding wonders concealed within the world’s
most unassuming corners. ■
26 Yale Scientific Magazine September 2023 www.yalescientific.org