For the first time ever, scientists have sequenced the genome of a man who was killed in the ancient city of Pompeii by the catastrophic volcanic eruption of Mount Vesuvius in 79 AD, a disaster that has inspired fear and awe for nearly 2,000 years, reports a new study.
The unprecedented achievement provides an intimate glimpse into the life of a man who was between 35 and 40 years old when the approach of a hot volcanic ash cloud likely killed him instantly inside one of the rooms of the Casa del Fabbro (House of the Craftsman) in Pompeii.
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While stray strands of human and animal DNA from Pompeii have been sequenced before, researchers led by Gabriele Scorrano, a geogeneticist at the University of Copenhagen, now present this “first successfully sequenced Pompeian human genome,” which reveals a man with complex ancestry and a potential tuberculosis infection, according to a study published on Thursday in Scientific Reports.
“To work with Pompeii is absolutely thrilling,” said Scorrano and Thomaz Pinotti, a PhD fellow at the University of Copenhagen, in a joint email. “Everything about the city is surreal or just too good to be true. We know where people lived, what they had in their houses, we even know the nasty things people wrote on the walls—if we know how to swear in Latin, it is because of Pompeii.”
The researchers noted that archaeologists usually have to rely on radiocarbon dating, among other methods, in order to determine the age of an ancient site. In contrast, we know that Pompeii and its ill-fated residents were buried in ash at about 1PM on August 24 in 79 AD, because a major intellectual figure, Pliny the Younger, happened to be a first-hand witness to the event, and documented the devastation from a safe distance across the Bay of Naples.
“In other words: there is just too much serendipity involved for all of this to be preserved,” Scorrano and Pinotti said, with “nothing more fitting than that one of the individuals had a DNA preservation good enough so it could be analyzed genetically by our team.”
Many of the buildings and bodies in Vesuvius’ blast zone remain exquisitely preserved even after nearly 2,000 years, due to the blanket of ash that rapidly entombed them. As a consequence of the sheer speed of the ash cloud, many victims of the eruption have been discovered in the position they died in, producing an eerie snapshot of the moment the city was destroyed that seems to defy the passage of time.
The team notes that more than half of Pompeii’s residents were inside their houses when they died, a detail that indicates “a collective unawareness of the possibility of a volcanic eruption or that the risk was downplayed due to the relatively common land tremors in the region,” according to the study.
This is the case for the man whose genome was just sequenced, known as individual A. Scorrano and his colleagues also attempted to sequence the genome of a middle-aged woman who died in the same room, known as individual B, but they were not able to extract enough data to complete that project. The remains of both victims were discovered “leaning on a low relief in a corner of what probably was the dining room, on the remnants of a triclinium, a sort of couch or chaise longue used in Roman buildings during meals,” the study noted.
While the bodies are physically well-preserved in many respects, extracting sequenceable DNA in these human remains is another matter. Indeed, Scorrano’s team was astonished when they were able to reconstruct the full genome of individual A using a sample extracted from the petrous bone near his ear, an achievement that the researchers said has been made possible by cutting-edge techniques.
“The biggest initial surprise on the particular individual is that it worked,” Scorrano and Pinotti said. “As a professor here in Copenhagen usually says, DNA is like ice cream—it lasts longer when it is cold. Being enveloped in a tsunami of 300ºC volcanic ash is then, well, suboptimal for DNA preservation.”
“Some attempts have been made on genetic analysis of Pompeian human and animal remains, however focusing on small fragments of DNA, not on genomes,” they continued. “There are trends and fine-scale details that we can assess now that would be possible using the previous methods.”
The successful sequencing of the man’s genome opens a window into his heritage and health status at the time he died in one of the most famous natural disasters of all time. The team found signs of the bacteria that causes the deadly disease tuberculosis, suggesting that the individual may have been infected at his time of death. They also cross-referenced his genetic history against 1,030 other ancient human remains, and 471 modern western Eurasian individuals, which revealed a complex ancestry filled with hidden surprises.
“On the purely genetics side, individual A looks very similar to other Imperial Roman Age genomes we have available, but with a twist,” Scorrano and Pinotti said. “Some of its genetic profile (the Y chromosome and the mitochondrial DNA) are very unusual for both the time and location. Actually both his lineages were very rare. What we believe it means is that he represents some Iron Age genetic diversity that was lost due to the homogenization of the Italic peninsula after the Roman Empire.”
These discoveries not only reveal interesting insights about this particular man, but also help to shape our understanding of populations living in Roman-era Italy as a whole. To that end, Scorrano and his colleagues plan to build on this success by attempting to sequence more genomes from the unlucky people and animals who were killed by this notorious disaster, as well as the cultures that preceded them.
“Future directions being explored by our team are to study other ancient populations in the Italian peninsula, such as the poorly understood pre-Roman Italic people, and how they contributed to present-day Italians,” Scorrano and Pinotti said. “Some of those, like the Etruscans, had huge impacts in today’s world through their influence with Romans,” they added, noting that the alphabet that you are currently reading is “actually an Etruscan adaptation of the Greek alphabet.”
“We hope palaeogenomics could help us to better understand the fascinating past of the Mediterranean region,” the pair concluded.
