Table 2.

Nucleotide divergence between gnd sequences at synonymous and nonsynonymous sitesa

Comparison (n)Divergence
Synonymous sites (dS × 100)Nonsynonymous sites (dN × 100)
O157 gnd alleleA(7)0.09 ± 0.090.09 ± 0.05
O157 gnd allele B(6)0.26 ± 0.190.10 ± 0.06
O157gnd allele C(2)0.29 ± 0.290.19 ± 0.13
O55gnd allele D(5)0.12 ± 0.120.04 ± 0.04
O157gnd alleles A, B, C(15)11.77 ± 1.350.28 ± 0.09
O157gnd allele A vs. ECOR 58 (2)9.52 ± 1.770.30 ± 0.17
O157gnd allele B vs. ECOR 29 (2)12.25 ± 2.030.30 ± 0.17
O157gnd allele C vs. ECOR 32 (2)15.47 ± 2.320.60 ± 0.25
O157:H7gnd allele D vs. O55:H7 allele D(2)130.52 ± 14.903.73 ± 0.60
  • a The degree of divergence at silent sites within each allele group is approximately one-tenth that of the difference between that allele group and the closest gndallele in the ECOR collection. The divergence between gndalleles of E. coli O157:H7 and E. coli O55:H7 is over 1,400 times greater than the divergence between gnd A alleles.