Molecular Typing and Mapping of MHC Class II-DRB3 Gene in Indian River Buffaloes ( Bubalus bubalis )

The present study was undertaken with the objectives of characterizing Bubu-MHC loci by PCR and genotyping MHC loci for allelic variation. The PCR product of second exon of the Bubu-MHC-DRB3 gene (304 bp) exhibited genetic polymorphism while digesting with HaeIII enzyme resulting in three restriction fragment patterns in Murrah, four in Surti and three in Murrah graded buffaloes. In all the three genetic groups, the pattern `b' (82, 222 bp) was frequently observed. The restriction fragment analysis with RsaI revealed five patterns in Murrah and three in Surti. The pattern `s' (67, 93, 144 bp) with a frequency of 0.4444 and `l' (67, 237 bp) with a frequency of 0.5000 were observed. Microsatellite typing revealed nine alleles ranging from 160 to 212 bp at the second intron. In Murrah, the allele 190 bp was observed exclusively. In Surti, alleles 192 and 212 bp were observed more frequently. RsaI enzyme revealed more polymorphic patterns of DRB3 than HaeIII. Microsatellite typing provided certain breed-specific alleles. This gene was physically localized to chromosome 2p following tyramide signal amplification in between bands 15-22 using (cDNA probes derived from Bos taurus cattle) fluorescence in situ hybridization.