Abstract：The study is conducted to investigate the association of B2M polymorphism with FcRn expression, in hope of improving the transportation of IgG in milk. The mammary gland samples were collected from 40 healthy Chinese Holstein cows immediately after slaughter and preserved in liquid nitrogen. We extracted total DNA from the frozen samples and designed specific primers to amplify B2M gene, followed by SNPs identification according to the sequencing results. The total RNA was purified from animal tissues according to the haplotypes of B2M, and then was transcripted reversely into cDNA. And the level of FcRn mRNA expression was detected by Real-time PCR. The results showed that there were three SNPs in B2M gene, which assembled four haplotype combinations. The expression of FcRn mRNA in H4 was significantly higher than that of the others(P<0.05), but there were no significant differences(P>0.05) between H1, H2 and H3. We conclude that the haplotype combinations of B2M have the effect on the expression of FcRn mRNA.
