Table 3. The estimation of non-synonymous (d _N) and synonymous (d _S) substitutions for antigen binding sites (ABS) and non-antigen binding sites (non-ABS) at MHC loci, with standard errors obtained through 1000 bootstrap replicates.

Locus	Position	N	dN	dS	dN/dS	P
Aime-DRB1	ABS	17	0.252±0.079	0.085±0.054	2.965	0.043
	Non-ABS	59	0.021±0.008	0.020±0.014	1.050	0.939
	All	76	0.065±0.016	0.034±0.016	1.912	0.137
Aime-DQA1	ABS	18	0.081±0.037	0.054±0.079	1.500	0.755
	Non-ABS	58	0.002±0.002	0.018±0.014	0.111	0.265
	All	76	0.021±0.009	0.026±0.015	0.808	0.931
Aime-DQA2	ABS	18	0.099±0.042	0.048±0.068	2.063	0.551
	Non-ABS	58	0.002±0.002	0.010±0.011	0.200	0.420
	All	76	0.025±0.010	0.017±0.012	1.471	0.644
Aime-DQA (DQA1 and DQA2)	ABS	18	0.124±0.047	0.111±0.098	1.117	0.909
	Non-ABS	58	0.002±0.002	0.010±0.010	0.200	0.409
	All	76	0.033±0.012	0.038±0.019	0.868	0.809

Abbreviation: MHC, major histocompatibility complex.

N is the number of codon, P is the probability that d_N and d_S are different by Z-test. Significant P-values (P<0.05) are typed in bold.

ABS, putative antigen binding sites as determined in Reche and Reinherz (2003).