author(s)
Dr. BV Reddy S and Dr. Sakaram D

abstract
The variability of the major histocompatibility complex (MHC) molecules is correlated with the diversity of the T-lymphocyte receptors which in turn determine the disease and parasite resistance of an organism and thus may influence the long term survival probability of populations. In cattle, DRA has not been investigated in depth, and the extent of variation at the locus is not yet known. In this study, we used PCR-RFLP analysis to screen for potential variation in the second and third exon of bovine DRA, which encodes the antigen-presentation groove/peptide binding region. Two unique patterns were detected among 50 Ongole cattle screened from India with Taq I and single pattern with Hae III Restriction Enzymes. The polymorphism detected may be linked to variation elsewhere in the gene that affects its structure or function. Further investigations with larger sample size; including cloning and sequence analysis may identify the complete polymorphism and potential breed specific alleles if any, which will increase the MHC, Class-II, DR receptors diversity. Present results may also be important in the context of the associations between MHC variations at this locus, with susceptibility to disease for this breed of cattle in further studies.