Characterization of MHC DRB3.2 Alleles of Crossbred Cattle by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism

The present investigation was undertaken to study the genetic polymorphism of the DRB3 exon 2 in 75 crossbred cattle by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Five genotypes i.e. HaeIII-a, HaeIII-b, HaeIII-e, HaeIII-ab and HaeIII-ae were observed when the 284 bp PCR products were digested with HaeIII restriction enzyme. The corresponding frequencies of these patterns were 0.53, 0.04, 0.01, 0.38 and 0.04, respectively. Digestion with RsaI restriction enzyme resolved 24 different restriction patterns. The frequencies of these patterns ranged from 0.013 (RsaI-f, RsaI-k and RsaI-c/n) to 0.120 (RsaI-n). The results revealed that the crossbred cows belonged to the RsaI patterns namely b, k, l, a/l, d/s, l/n, l/o and m/n, whose corresponding frequencies were 0.027, 0.013, 0.040, 0.027, 0.040, 0.067, 0.027 and 0.067, respectively. Digestion of the 284 bp PCR product of DRB3.2 gene with PstI in the crossbred cattle did not reveal any restriction site. These results suggested the absence of the recognition site in some of the animals. These results also revealed that the crossbred cows studied were in homozygous as well as heterozygous condition. On the basis of the above results it can be concluded that the DRB3.2 gene was found to be highly polymorphic in the crossbred cattle population.