DNA polymorphism of BoLA-DRB3.2 gene in Tharparkar cattle (Bos indicus) by PCR-RFLP

PCR-RFLP study of BoLA-DRB3 exon 2 was carried out in 36 Tharparkar cattle using three restriction enzymes namely HaeIII, RsaI and PstI. Two genotypes i.e. HaeIII-aa and HaeIff-ab with frequencies 0.833 and 0.167 and major fragment sizes as 167, 52 and 65 and 219, 167, 52 and 65, respectively, were observed when the 284 bp PCR products were digested with HaeIII restriction enzyme. Digestion with RsaI revealed 10 different patterns (I, II, III, IV, V, I / II, I / III, I / III, III / ? and I / ?) and out of these five alleles were new and all these alleles were in heterozygous conditions. The frequencies of these were 0.031, 0.156, 0.281, 0.125, 0.156, 0.063, 0.031, 0.063, 0.063 and 0.031, respectively. 75% animals were found homozygous for RsaI enzyme site. The results revealed loss of polymorphism of DRB3 haplotypes. However, further studies may help to understand the mechanisms of loss of polymorphism.