Comparison of bovine lymphocyte antigen DRB3.2 allele frequencies between two subpopulations of Iranian holstein cattle

The bovine lymphocyte antigen (BoLA-DRB3) gene encodes cell surface glycoproteins that initiate immune responses by presenting processed antigenic peptides to CD4 T helper cells. DRB3 is the mostpolymorphic bovine MHC class II gene which encodes the peptide-binding groove. Since different alleles favor the binding of different peptides, DRB3 has been extensively evaluated as a candidatemarker for associations with various bovine diseases and immunological traits. Therefore, in this study, the genetic diversity of the bovine class II DRB3 locus in the two Iranian subpopulations of Holstein cattle (Moghan farm n = 250 and Razavi farm n = 175) was investigated by polymerase chain reactionrestriction fragment length polymorphism method (PCR-RFLP). Bovine DNA was isolated from whole blood. A hemi-nested PCR followed by digestion with restriction endonucleases RsaI, HaeIII and BstYI was conducted on the DNA. The results indicated that exon 2 of the BoLA-DRB3 gene is highlypolymorphic in the two populations, and the frequency of BoLA-DRB3 depends on breed. On the other hand the presence of BoLA-DRB3*8, *24, and *16 alleles with high frequency in BoLA-DRB3.2 system,can be used as appellative index for nominate Holstein