GENETIC POLYMORPHISM OF GDF9 GENE IN LORI-ROMANOV CROSSBREEDS SHEEP BY PCR-RFLP

INTRODUCTION: Genetic variation in ovulation rate in sheep has been widely documented and the evidence shows substantial differences among world sheep breeds. Candidate gene approach and DNA marker strategy are new tools to improve this trait in populations. Mutations in GDF9 gene are associated with increased ovulation rate and infertility in a dosage-sensitive manner and this gene is essential for normal folliculogenesis in sheep. The discovery of major genes with large effects on ovulation rate and thus litter size has generated considerable interest among sheep breeders and scientists. This project conducted to analysis on GDF9 gene polymorphism in Lori-Romanov crossbreed sheep.MATERIALS AND METHODS: Blood samples were collected from 100 Lori-Romanov lambs. Genomic DNA was extracted by Kit method. A 462bp fragment from exon1 region of GDF9, gene was amplified using polymerase chain reaction and after that PCR product digested with HhaI restriction enzyme. All digested PCR products were separated by 3.0% agarose gel and visualized with supper red gel staining under gel documentation system. After genotyping, data was analyzed by Pop Gene software.RESULTS AND DISCUSSION: Digested PCR products with HhaI enzyme showed a G to A substiuation in exon 1 of the GDF9 locus. Restriction digestion of the PCR product from wild type animals with HhaI resulted in cleavage of the 462 bp product into fragments of 52 bp, 156 bp and 254 bp. However, DNA fragments containing the mutant allele yield only two fragments (52 bp and 410 bp). Animals heterozygous for the mutation have fragments of all four sizes (52 bp, 156 bp, 254 bp and 410 bp). Genotype frequencies for G (+/+), G (+/-) and G (-/-) were 0.6, 0.4 and 0, respectively. The population was not found to follow Hardy-Weinberg equilibrium. It may conclude that the genetic factor controlling twinning in crossbreed sheep is related to this mutation. This mutation may be important for MAS viewpoint.

کلیدواژه ها:

Lori-Romanov ، sheep ، GDF9 Gene ، Polymorphism ، PCR-RFLP