Ancient teeth from Siberian graves push plague's origins back to over 5,500 years ago

The find

Scientists have identified genetic material from Yersinia pestis, the bacterium responsible for plague, in teeth excavated from burial sites in Siberia dating back more than 5,500 years, according to AP News. That pushes the confirmed record of the pathogen back by approximately 1,000 years compared to previously known ancient samples.

The specimens came from cemeteries in the region. Researchers extracted and sequenced ancient DNA from the dental pulp, which is among the most reliable tissue for recovering genetic material from remains that old.

Why teeth?

Dental pulp is protected by hard enamel and dentin, which slows degradation. Bacteria circulating in the bloodstream at the time of death can become trapped there, making teeth a well-documented archive for ancient pathogen research. This method has been used in previous plague studies and is considered standard practice in the field of ancient DNA analysis.

What the earlier strain tells us

The ancient strain recovered from these Siberian individuals appears to be an earlier, less-evolved version of the pathogen compared to strains associated with later, historically documented plague outbreaks.

Researchers studying the evolutionary history of Y. pestis have been working to trace when and how the bacterium acquired the specific genetic traits that made later strains so lethal and so efficient at spreading between humans. Each older sample found in the archaeological record adds a data point to that map.

What this changes

The Siberian specimens, if the dating and identification hold up under peer scrutiny, extend the known window of Y. pestis circulation in human populations meaningfully, rewriting the plague's timeline by over 1,000 years, according to AP News.

The implication is that Y. pestis was circulating in human populations during the late Neolithic and early Bronze Age, a period of significant population movement across Eurasia. Some researchers have theorized that plague, or at minimum the broader stress of infectious disease, played a role in the demographic shifts visible in the archaeological record from that era.

The strongest skeptical case

Ancient DNA research, for all its advances, carries real methodological risks. Contamination from modern bacteria or from other ancient material at the excavation site can produce false positives. Dating of remains relies on the context of the burial and, where available, radiocarbon analysis, both of which carry margins of error. Critics of ancient pathogen studies routinely point out that identifying fragments of Y. pestis DNA does not automatically confirm the individual died of plague, or even that plague was present in the community at a meaningful prevalence. These are legitimate scientific concerns, and independent replication of the findings is the standard by which claims this significant get validated.

The AP News report's available content does not detail the full methodology, sample sizes, or whether the findings have been published in a peer-reviewed journal as of the reporting date. Those specifics matter for evaluating how settled this conclusion actually is.

The longer arc

Plague is not a relic pathogen. Understanding the evolutionary history of the bacterium has direct relevance to understanding how it might continue to change.

The Siberian find fits into an accelerating pace of ancient DNA discovery over the past decade, driven largely by improvements in sequencing technology and the growing number of excavations applying genomic analysis to skeletal remains. Each older confirmed sample narrows the range of hypotheses about where and when plague first jumped to humans from its animal reservoir, most likely rodents.

The open question the scientific community now faces is whether samples even older than these Siberian teeth exist somewhere in the archaeological record, and whether the pathogen's earliest human hosts were experiencing something recognizable as plague or simply carrying a precursor bacterium that had not yet evolved its most dangerous traits.