FIG. 4.

(A) Tree of the vtp sequences of the B. hermsii isolates and ospC of B. burgdorferi B31 used for the outgroup. The tree was constructed and analyzed as described for Fig. 2. All isolates in GGII are distinguished from GGI isolates with bold and underlined names. Probable examples of horizontal transfer of vtp sequences between spirochetes in the two genomic groups are shown within dashed-line boxes. (B) Distribution of polymorphic sites in the vtp gene for all isolates in each genomic group. A sliding window of 100 with a step size of 25 bases was used for same length alignments of the vtp genes. The mean nucleotide diversity (π) is on the y axis in relation to the nucleotide position on the x axis.