Ancient Yersinia pestis DNA Unearthed in New Study
Researchers have identified ancient DNA from Yersinia pestis—the bacterium responsible for plague—in over a dozen individuals who died from previously unknown strains. This discovery suggests the disease was likely pneumonic plague, transmitted from wild marmots, and it ravaged family groups living near Lake Baikal. The findings challenge the long-held assumption that plague epidemics first emerged only after the advent of agriculture.
Published in the journal Nature, the study analyzed teeth from 46 people buried at four cemeteries along the Angara River. Yersinia pestis was detected in 18 of them, with children being the most frequent victims. The first outbreak occurred roughly between 5,596 and 5,341 years ago, and a second between 5,126 and 4,926 years ago. One grave held the remains of three close female relatives, while another contained an aunt and her nephew.
According to Ruairidh Macleod, the study’s lead author and a researcher in ancient genomics at the University of Oxford:
“We got a really striking result—we found a lot of plague here much earlier than we expected.”
The ancient DNA from the hunter-gatherers revealed two newly identified plague strains carrying a unique gene that codes for proteins capable of triggering massive immune responses.
Historical Context and Modern Relevance
These findings also shed light on the history of plague epidemics. The Plague of Justinian, the first documented pandemic, began around 1,500 years ago, while repeated outbreaks have been identified between 5,300 and 4,900 years ago among farmers in what is now Scandinavia. Macleod notes that:
“This is as close as we will ever get to proving the virulence [the ability of microbes to cause disease] of these early epidemics.”
Today, the strain of Yersinia pestis that causes epidemics spreads mainly in Africa. In the United States, an average of seven plague cases are reported each year. Modern cases detected early can be treated with antibiotics. The team’s discovery opens new avenues for studying ancient epidemics and their impact on humanity.
This research matters not only for medical history but also for understanding how pathogens evolve and adapt. Identifying ancient Yersinia pestis strains could reshape our understanding of when and how plague epidemics arose in human populations, as well as their effects on social structures and lifestyles. The studied strains may hold critical insights for modern science, including the development of new strategies to combat infectious diseases.