TABLE 4.

Results of McDonald-Kreitman tests of neutral evolution of the chromosomal beta-lactamase gene of K. pneumoniae

Group 1Group 2No. of fixed differences between group 1 and group 2No. of polymorphisms observed within groups 1 and 2GaPb
SynonymousNonsynonymousSynonymousNonsynonymous
KpIKpII482730271.710.19
KpIKpIII422317140.820.36
KpIIKpIII382732310.750.39
TEM-1cKpI + KpII + KpIII1448598590.0080.93
  • a G tests of independence were performed using William's correction.

  • b Probability of finding a larger difference between the ratios of synonymous to nonsynonymous changes by chance alone.

  • c TEM-1 was included as the closest relative, in order to check for neutral evolution since the separation of TEM from the branch containing SHV, LEN, and OKP.