Figure 1. Existing phylogeny of Francisella tularensis subsp. holarctica. A) Single nucleotide polymorphism (SNP)–based phylogeny of F. tularensis subsp. holarctica derived from previous studies (5,6,8). Terminal subgroups representing sequenced strains are shown as stars, and intervening nodes representing collapsed branches are indicated by circles. Subclades within group B.13 are depicted in red. Isolates from Austria, Germany, Hungary, Italy, and Romania (n = 45) were assigned to existing subclades (black arrows) by using existing canonical SNP assays (5,8). B) Maximum parsimony phylogeny constructed by using SNPs discovered from 6 F. tularensis whole-genome sequences, including 5 strains from group B.13 and an outgroup strain, OSU18 (not shown). This phylogeny was rooted by using OSU18, and bootstrap values were based on 1,000 simulations by using a heuristic search. The newly sequenced Hungarian strain (Tul07/2007) is highlighted in gray.