5,500-Year-Old Colombian Remains Reveal Ancient Treponema pallidum Genome
Scientists have successfully reconstructed the genome of Treponema pallidum from human remains approximately 5,500 years old,discovered in the Sabana de Bogotá region of Colombia.This bacterium causes several serious infectious diseases today, including syphilis. The findings, published in the journal Science, considerably expand researchers’ understanding of how long thes infections have affected human populations.
The remains were excavated from a rock shelter near present-day Bogotá and date back roughly 5,500 years. by identifying this ancient genome, researchers have extended the known genetic history of Treponema pallidum by more than 3,000 years. The evidence supports the idea that treponemal diseases circulated in the Americas earlier than previously documented.
“our findings show the unique potential of paleogenomics to contribute to our understanding of the evolution of species and potential health risks for past and present communities,” said geneticist Lars Fehren-Schmitz at the University of California, Santa Cruz.
What Are Treponemal Diseases?
Treponema pallidum is a spiral-shaped bacterium that exists today in three closely related subspecies. Each causes a different disease: syphilis,yaws,and bejel. A fourth treponemal disease,pinta,is caused by Treponema carateum or Treponema pallidum subsp.carateum. No complete genome of the pathogen responsible for pinta has yet been recovered, leaving questions about its evolutionary relationships and classification.
Despite their nearly identical genetic makeup, scientists do not know when or how these different disease forms emerged. While skeletal remains can sometimes show signs of infection,genetics frequently enough tell a more complex story. Large gaps remain between what bones reveal and what ancient DNA confirms about disease evolution.
A Lost Lineage of a Familiar Pathogen
In this study, researchers confirmed that the ancient DNA belonged to the species Treponema pallidum, but it did not match any of the known forms that cause disease today. Although closely related to modern strains, the ancient genome split off early in the bacterium’s evolutionary history.
“One possibility is that we uncovered an ancient form of the pathogen that causes pinta, which we know little about but is endemic in Central to South America and causes symptoms localized to the skin,” said Anna-Sapfo Malaspinas at the University of Lausanne and group leader at the SIB Swiss Institute of Bioinformatics.”At this time, we cannot prove this is the case, but it is indeed a lead worth investigating further.”
Based on genetic analysis, scientists estimate that this ancient strain separated from othre T. pallidum lineages about 13,700 years ago. In contrast, the three modern subspecies appear to have diverged much later, around 6,000 years ago. These timelines support earlier research and highlight the diversity of treponemal pathogens.