FIG. 2.

Eight bfpA alleles cluster into two major groups. To the left is a phylogenetic tree for the bfpA gene from 17 EPEC strains constructed by the neighbor-joining algorithm based on the gamma distance with α = 2. Branch lengths in terms of nucleotide substitutions per 100 sites are given above the major branches. Allele designations are listed for each strain. To the right is a graph of the locations of polymorphic nucleotide sites, which are marked as vertical lines that indicate nucleotides differing from those of the α2 allele at each position. Gaps indicate codons absent from specific alleles.