Neighbor-joining phylogeny constructed from 16S rDNA gene sequences. Sequences were obtained from the clinical human isolate, other F. tularensis isolates, and isolates from related species. The tree, which was created using MEGA2 software , is midpoint rooted. Bootstrap values ≥ 60 are presented and are based upon 1,000 replicates. The human clinical isolate clusters with the F. tularensis strains; right vertical bar indicates F. tularensis clade. Sequences with an asterisk (*) were generated as part of this study. All other sequences were obtained from GenBank. Accession numbers for all sequences are shown in parentheses. The scale bar, expressing mean character difference, corresponds to 0.02 substitutions per nucleotide position.