Genetic variation of major histocompatibility complex BLB2 gene exon 2 in Hebei domestic chicken.

Genetic variation of MHC BLB2 gene exon 2 in Hebei domestic chicken was investigated, after PCR and sequencing of a 374bp fragment (containing entire exon 2 (270bp) of BLB2 gene) in 76 individuals. The results showed that along this fragment, there were 69 variable sites, of which 18 were novel variations, and 82 estimated haplotypes with the diversity of 0.960. In Hebei domestic chicken, the nucleotide diversity (π), the average number of nucleotide differences (k), the average number of nucleotide diversity of synonymous substitution (π(s)) and non-synonymous substitution (π(a)) in BLB2 gene exon 2 were 0.098, 24.688, 0.075, and 0.106, respectively; nine non-synonymous substitutions was exclusively found in the peptide-binding sites (PBS) region of BLB2 gene exon 2, inferring that these unique substitutions might be helpful to resist some special bacteria and pathogens. The higher genetic diversity of MHC BLB2 gene exon 2 in Hebei domestic chicken might be consistent with its more robust disease resistance.