FIG. 1.

Phylogenetic trees based on gene sequences as indicated and calculated by using the maximum likelihood algorithm in the BIONUMERICS software package, version 4.0 (Applied Maths). One representative isolate from each sequence type (Table 3) was included in the computations. When available, gene sequences from Francisella philomiragia isolates (indicated by asterisks) were included as outgroups to enable bootstrap analyses of the deepest nodes within the F. tularensis clade. Bootstrap values from 100 resamplings are indicated when they are at least 90%. They are based on both the maximum-parsimony and neighbor-joining algorithms and were computed by using PHYLIP 3.65. Subspecies affiliations are indicated in the tree based on concatenated gene sequences. Scale bars indicate percent sequence similarity.