The genus Yersinia consists of a heterogeneous collection of organisms, comprising the highly pathogenic species Yersinia pestis, enteropathogens Yersinia pseudotuberculosis and Yersinia enterocolitica as well as environmental species. The evolutionary history of Y. pestis has been well documented, but information on the evolutionary relationship between the other Yersiniae is less characterized. Y. enterocolitica is a diverse species classed into six different biotypes (BT), but only a single genome sequence for high-pathogenic BT 1B was available at the start of the project
