Analysis of Bovine Growth Hormone Gene Polymorphisms in Three Iranian Native Breeds and Holstein Cattle by RFLP-PCR

The aim of this study was to estimate the allelic frequency in polymorphic sites of intron 3 and exon 5 of bovine growth hormone gene in three Iranian native and Holstein cattle. A total of 406 genomic DNA samples were extracted from three Iranian native cattle including, Mazandarani 97, Sarabi 87, Golpaygani 112 and Holstein 110 cattle. The PCR procedure was used to amplify 345 bp of bGH-intron 3 and 404 bp of bGH-exon 5. The frequencies of MspI (+) allele were estimated as 0.55, 0.51, 0.44 and 0.83 in Mazandarani, Sarabi, Golpaygani and Holstein breed, respectively. The allelic frequencies of AluI (+) were calculated as 0.91, 0.84, 0.92, 0.85 and for DdeI (+), 0.52, 0.54, 0.47 and 0.86, for these breeds, respectively. Chi-square test showed significant differences (p<0.01) in genotypic frequency between native and Holstein breed in MspI and DdeI restriction sites. There was significant differences in genotypic frequencies between Mazandarani (p<0.05) and Golpaygani (p<0.01) with Holstein breed at AluI restriction site. This difference was not significant between Sarabi and Holstein breed. The differences in allelic frequency between native breeds and Holstein cattle at the present study might be due to differences in origin of breeds, selection plans applied to Holstein population for improving milk production.