TABLE 2.

Comparative mutation rates and predicted recombination sites for acrA, acrB, and MLST alleles

LocusNo. of:dSadNbdS/dNφwcGARD breakpointsd
LociUnique allelesSitesVariable sites
acrA e 1261,194430.0180 ± 0.00330.0014 ± 0.000512.860.0464None
acrA (genome)f1131,194360.0198 ± 0.00390.0024 ± 0.00088.250.1310
acrB 1423,1501700.0295 ± 0.00290.0006 ± 0.000149.171.8E-041065, (1563),g 2064
acrB (genome)1203,1501540.0388 ± 0.00380.0011 ± 0.000335.278.8E-051065, 1701, 2238
MLSTh (genome)7193,7322430.0554 ± 0.00410.0016 ± 0.000334.63N/AN/A
  • a Mean synonymous mutation rate per synonymous site ± standard error.

  • b Mean nonsynonymous mutation rate per nonsynonymous site ± standard error.

  • c Calculated using SplitsTree4, with a value of <0.05 suggesting potential recombination. N/A, not applicable.

  • d Nucleotide locations of recombination breakpoints in the acrB coding sequence (see also Fig. 1A, arrows).

  • e Complete allele group consisting of isolates in this study and sequences from genome repositories (see the legend to Fig. 2).

  • f Allele group consisting only of available sequences from genome repositories.

  • g (1563), additional breakpoint identified in intragenic fragment 1065 to 2064 when analyzed independently.

  • h Concatenated E. coli MLST alleles: aspC, clpX, fadD, icdA, lysP, mdh, and uidA (18).