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Image Credit: Grace2202, CC BY-SA 4.0, via Wikimedia Commons
Bolivian Mummy Yields Earliest Confirmed Genome of Streptococcus in the Americas
Researchers have reconstructed an ancient genome of Streptococcus pyogenes—the bacterium responsible for illnesses such as strep throat—from a pre-Columbian mummy in Bolivia, providing the earliest confirmed evidence of the pathogen in the Americas before European contact. The individual, a naturally mummified young adult from the Late Intermediate Period, has been radiocarbon dated to 1283–1383 AD.
The study was based on DNA recovered from a tooth of the mummified individual, whose mitochondrial DNA confirmed Indigenous American ancestry. Metagenomic analysis allowed researchers to assemble a near-complete ancient bacterial genome and compare it with modern strains. The results showed that the ancient strain shares many important features with present-day S. pyogenes, including core virulence genes associated with infection, while lacking certain toxin genes that in modern strains are often linked to bacteriophages.
Phylogenetic analysis placed the Bolivian strain near the base of known S. pyogenes diversity, indicating that it represents a deeply diverged lineage. According to the study, this pushes back the confirmed presence of the pathogen in the Americas by several centuries and shows that it was already circulating among Indigenous populations long before the colonial period.
The authors also suggest that the strain was likely adapted to throat infections rather than skin disease, based on its genetic profile and comparison with modern lineages. More broadly, the research highlights how ancient DNA can help trace the deep history of infectious disease and refine understanding of how important human pathogens evolved and spread across the world.
The study further proposes that most modern S. pyogenes lineages diversified within the last roughly 5,500 years, offering a new framework for examining the long-term evolution of one of the world’s most significant human bacterial pathogens.
Published on: 18-04-2026
Edited by: Abdulmnam Samakie
Source: Nature Communications
