Polymorphisms in third intron of growth hormone of Guilan native cows using PCR-RFLP markers

Bovine growth hormone(bGH) gene, is a part of the multiple gene family that contains prolactin and placental lactogens. The variations in the introns of this gene, have potential usefulness as genetic markers and could help in the genetic improvement of populations. In ordre to investigate allele frequency of MspI in introne 3 of growth hormone gene of Guilan native cattle breed, blood samples were collected from seventy heads of randomaly choosen cattles (cows). Genomic DNA was extracted from these samples, using modified salting out method. Polymerase chain-reaction (PCR) procedure was used to amplify a 345 bp segment in this region and then digested with MspI restriction enzymes. Digested samples were run on the acrylamid gel 8% to recognize their genotype. This enzyme had two restriction sites and after digestion with MspI enzyme on that fragment and 2 allels and 3 genotypes have been observed. Frequency of MspI(+) allele was estimated to 0.4643. X2 test has showed the equilibrium of frequency MspI in samples.