Abstract：BoLA-DRB3 is a member of the MHC (Major Histocompatibility Complex), which plays a central role in immune system and disease resistance of bovine. The exon2 of BoLA-DRB3 gene is a mainly functional region, which codes the antigen and participates in the body's immune response. In this study, The restriction polymorphism of the exon2 of BoLA-DRB3 in Luxi，Nanyang and Jinnan cattle were investigated by PCR-RFLP. 6 genotypes and 3 alleles were identified for BoLA-DRB3 locus. Statistical results showed that polymorphism sites at position 154、155、156 and 157 in Luxi catttle and Jinnan cattle fitted Hardy-Weinberg equilibrium, but not in Nanyang cattle. After sequencing, 13.70% of nuclitide mutated, which induced that 14.61％ of amino acid changed.
