Toward a Molecular History of Yersinia pestis

Technological advances in the last two decades have revolutionized our study of microbial evolution. Not only is it practical to sequence the entire genome of multiple strains of a microbe to reconstruct its family (phylogenetic) tree, but ancient DNA (aDNA) technology has advanced to the point that we can now sequence genomes from archaeological remains. Nowhere can this work inform our understanding of history more than for Yersinia pestis, better known as ‘the plague’.

A large multinational group recently published a consensus phylogenetic tree for Yersinia pestis using clones from Asia, Africa, North and South America that allows us characterize the plague’s biogeography, genetic diversity, approximately when and where it originated, and to begin to track transmission routes. It is an evolutionary map to Yersinia pestis’ history. Ancient DNA has not only confirmed Yersinia pestis as the cause of the medieval plague, but also allows us to begin to tack parts of this evolutionary map in space and time including the initial wave of the Black Death. This session will also discuss the state of the molecular evidence for the medieval plagues.