Yersinia pestis is back in the news due to ancient plague findings and fresh links to medieval trade—here’s the quick bio remix: a gram-negative, non-motile bacterium, causes bubonic/plague; related to Y. pseudotuberculosis and Y. enterocolitica; facultative anaerobe; no spores.
New genetic analysis links two ancient outbreaks of plague to early hunter-gatherer groups near Lake Baikal, showing the disease evolved long before the Black Death and spread from marmots to people.