Figure 1

Unrooted consensus phylogram of the concatenated mrkABCD nucleotide fragments. Majority-rule consensus tree was based on 500 bootstrap replicates using dnaml, the DNA maximum likelihood algorithm implemented by PHYLIP [54]. Five well-supported clades are labelled A-E; the largest clade, A, is circled. Bootstrap values are shown; small asterisks next to branches denote 100% support. Taxon IDs include species name abbreviations as suffixes (Cf, C. freundii indicated in black; Ck, C. koseri indicated in green; Ec, E. coli indicated in blue; Ko, K. oxytoca indicated in orange; and Kp, K. pneumoniae indicated in red), followed by the strain name. Taxon IDs highlighted in bold and underlined refer to those used in further analyses of the complete sequence of their respective mrk locus. Complete mrk locus sequences available from GenBank are marked with a large asterisk next to the strain name.