title: Microevolution and history of the plague bacillus, Yersinia pestis.
abstract: The association of historical plague pandemics with Yersinia pestis remains controversial, partly because the evolutionary history of this largely monomorphic bacterium was unknown. The microevolution of Y. pestis was therefore investigated by three different multilocus molecular methods, targeting genomewide synonymous SNPs, variation in number of tandem repeats, and insertion of IS100 insertion elements. Eight populations were recognized by the three methods, and we propose an evolutionary tree for these populations, rooted on Yersinia pseudotuberculosis. The tree invokes microevolution over millennia, during which enzootic pestoides isolates evolved. This initial phase was followed by a binary split 6,500 years ago, which led to populations that are more frequently associated with human disease. These populations do not correspond directly to classical biovars that are based on phenotypic properties. Thus, we recommend that henceforth groupings should be based on molecular signatures. The age of Y. pestis inferred here is compatible with the dates of historical pandemic plague. However, it is premature to infer an association between any modern molecular grouping and a particular pandemic wave that occurred before the 20th century.
authors.affiliation: Department of Molecular Biology, Max-Planck Institut für Infektionsbiologie, D-10117 Berlin, Germany. achtman@mplib-berlin.mpg.de
authors.forename: Mark
authors.initials: M
authors.lastname: Achtman
authors.forename: Giovanna
authors.initials: G
authors.lastname: Morelli
authors.forename: Peixuan
authors.initials: P
authors.lastname: Zhu
authors.forename: Thierry
authors.initials: T
authors.lastname: Wirth
authors.forename: Ines
authors.initials: I
authors.lastname: Diehl
authors.forename: Barica
authors.initials: B
authors.lastname: Kusecek
authors.forename: Amy J
authors.initials: AJ
authors.lastname: Vogler
authors.forename: David M
authors.initials: DM
authors.lastname: Wagner
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Allender
authors.forename: W Ryan
authors.initials: WR
authors.lastname: Easterday
authors.forename: Viviane
authors.initials: V
authors.lastname: Chenal-Francisque
authors.forename: Patricia
authors.initials: P
authors.lastname: Worsham
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Thomson
authors.forename: Julian
authors.initials: J
authors.lastname: Parkhill
authors.forename: Luther E
authors.initials: LE
authors.lastname: Lindler
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Carniel
authors.forename: Paul
authors.initials: P
authors.lastname: Keim
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D019143:Evolution, Molecular; D016680:Genome, Bacterial; D006801:Humans; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D010930:Plague / Q000453:epidemiology / Q000382:microbiology*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D015010:Yersinia pestis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000502:physiology
chemical_list: D001426:Bacterial Proteins