Characterization of genetic polymorphism of the bovine lymphocyte antigen DRB3.2 locus in Kankrej cattle (Bos indicus)

Bovine lymphocyte antigen DRB 3.2 (BoLA-DRB3.2) gene encodes for the beta chain of the major histocompatibility complex (MHC) class II molecule in cattle, which is a glycoprotein present on the surface of antigen-presenting cells. This locus shows extensive polymorphism in it. The objective of the present study was to genotype the BoLA-DRB3.2 locus in Kankrej cattle (n = 50) by PCR-RFLP. Bovine DNA was isolated from aliquots of whole blood. Primers specific for exon 2 of the bovine lymphocyte antigen (BoLA)-DRB3 gene were used to amplify the region. The 304-bp amplified product of the DRB3 gene was separately digested with restriction endonucleases RsaI, BstYI, and Hae III. Twenty-four BoLA-DRB 3.2 alleles were identified with frequencies ranging from 1 to 22.0%. Twenty-one alleles of the total 24 alleles were similar to those reported earlier; 3 alleles were new and had not been reported previously. The allele BoLA-DRB3.2*34 occurred at the highest frequency of 22% (approx.) in the Kankrej animals studied. Six alleles (BoLA-DRB3.2 *34, *15, *06, *20, *37, and *20) accounted for almost 71% of the total alleles observed to be present in the Kankrej animals. All the new alleles observed were present at frequencies of 1%. The results obtained in the present study demonstrated that the BoLA DRB3.2 locus is highly polymorphic in the Kankrej cattle.