How the plague developed
International team of researchers investigates the pathways of the bacterium Yersinia pestis in Eurasia from 5,000 to 2,500 years ago
Reconstructed plague genomes reveal important stages in the early evolution of the plague bacterium, a study finds. As early as 5,300 years ago, Yersinia pestis caused plague in human populations. Relatively little is known about the genetic diversity, geographic spread, and transmission dynamics of the bacterial pathogen during its early evolution. Aida Andrades Valtueña, Wolfgang Haak, Johannes Krause, Alexander Herbig, and colleagues, among them Dr. Maria Spyrou from the Institute for Archaeological Sciences of the University of Tübingen, screened tooth samples from 252 individuals at 15 archeological sites across Eurasia and reconstructed 17 Y. pestis genomes dated to 5,000 to 2,500 years ago.
The analysis revealed that genetically distinct flea-adapted and non-flea-adapted forms of Y. pestis likely co-existed and evolved in parallel across vast regions of Western Eurasia for at least 2,500 years. The discovery of a flea-adapted lineage in Bronze Age Iberia expands the known geographic range of this form of the pathogen beyond central Eurasia and highlights the diversity of strains present in Eurasia shortly after the possible emergence of Y. pestis.
The non-flea-adapted lineage may have become extinct after the Iron Age. Together with archeological evidence, the results suggest that the spread of plague during this period was linked to increased human mobility, marked by the intensification of pastoralism, and enabled by the spread of ox-drawn carts and wagons as well as horse domestication. According to the authors, the findings reveal important stages in the early evolution of the plague pathogen.
Press summary of the Proceedings of the National Academy of Sciences (PNAS)
Aida Andrades Valtueña, Gunnar U. Neumanna, Maria A. Spyroua, Lyazzat Musralinab et al.: Stone Age Yersinia pestis genomes shed light on the early evolution, diversity, and ecology of plague. PNAS, https://doi.org/10.1073/pnas.2116722119
Dr. Maria Spyrou
Max Planck Institute for Evolutionary Anthropology and
University of Tübingen – Institute for Archaeological Sciences