Table 3.

Mean numbers of nucleotide substitutions per non-synonymous site (d_N) and synonymous site (d_S) and the d_N/d_S ratios (ω)

Mamu-DQB1	Sites	n	dN	dS	ω	P
Dataset A	ABS	16	0.312 ± 0.073	0.214 ± 0.089	1.458	0.163
	Non-ABS	73	0.082 ± 0.018	0.084 ± 0.021	0.976	0.483
	All	89	0.118 ± 0.020	0.103 ± 0.020	1.146	0.279
Dataset B	ABS	16	0.251 ± 0.081	0.123 ± 0.068	2.041	0.039*
	Non-ABS	73	0.082 ± 0.018	0.078 ± 0.017	1.051	0.427
	All	89	0.106 ± 0.020	0.085 ± 0.017	1.247	0.192

Notes: Dataset A represented 23 Mamu-DQB1 alleles in this study;Dataset B represented currently 69 Mamu-DQB1 alleles including 46 alleles from IPD. ABS, the putative amino acid residues involved in antigen binding region (site 9, 11, 13, 28, 47, 57, 61, 67, 70, 71, 74, 78, 85, 86, 89 and 90), were identified according to the corresponding antigen binding sites identified in human HLA-DR and DQ structure (72). n, the number of codons encoding amino acid; Statistical significance is indicated by the asterisks (P <0.05).