We used whole-genome analysis and subsequent characterization of geographically diverse strains using new genetic signatures to identify distinct subgroups within Francisella tularensis subsp. tularensis group A.I: A.I.3, A.I.8, and A.I.12. These subgroups exhibit complex phylogeographic patterns within North America. The widest distribution was observed for A.I.12, which suggests an adaptive advantage.
Keywords: Francisella tularensis; Francisella tularensis subsp. tularensis; SNP; United States; bacteria; geographic distribution; group A.I; phylogeography; single-nucleotide polymorphism; subgroup; tularemia.