Genetic polymorphism of DGAT1 gene in Mandya and Hassan Sheep of Karnataka

Abstract

A study was carried out to identify and compare the genetic polymorphism in ovine DGAT1 (Diacylglycerol acyltransferase 1) gene of Mandya and Hassan sheep using PCR-RFLP (polymerase chain reaction – restriction fragment length polymorphism) technique. A total of 100 unrelated animals, 50 each of Mandya and Hassan sheep from farmers’ flocks in the respective breeding tracts were utilized. A 309 bp fragment of ovine DGAT1 gene sequence spanning exons 16–17 and the intervening intron was amplified by PCR employing previously published primers. The RFLP analysis using AluI restriction enzyme, polymorphic pattern revealed two alleles viz., allele C (309 bp fragment) and allele T (272 and 37bp fragments) and three genotypes, CC, CT and TT. The frequencies of CC, CT and TT genotypes were 0.84, 0.16 and 0.00 in Mandya and 0.86, 0.12 and 0.02 in Hassan sheep, respectively. The allelic frequencies for C and T alleles in Mandya and Hassan sheep were 0.92 and 0.08, respectively. Allele C and genotype CC were predominant in both the sheep populations. The sequence analysis revealed two SNPs viz., T->A (transversion) and C->T (transition) at positions 103 and 274 bp, respectively in T allele sequence of ovine DGAT1 gene. BLASTn sequence analysis showed 99% homology with predicted ovine DGAT1 gene (EU178818.1) sequence. Thus, genetic polymorphism was established at exon 1617 locus of ovine DGAT1 gene by PCR-RFLP and two SNPs were identified.