Cobra Moradian, Giti esmailnia and Abbas Hajihosseinlo
The native breeds, because of their natural selection against harsh environment and adaptation to regional conditions are important to resource-poor farmers and pastoralists. The IGF1 gene (insulin-like growth factor 1) is a candidate gene for marker-assisted selection strategies.IGF-1 gene that has located on chromosome 3 in sheep is a marker for growth rate and meets production and has an important role in mammary glands cell differentiation and proliferation. Genomic DNA was isolated from the blood of 100 sheep. Gel monitoring and spectrophotometer methods were used to determine the quality and quantity of DNA. A 265bp IGF-1 exon 1 segment was amplified by standard PCR, using the locus specific primers. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis of the 5’ flanking region (Exon1) of the ovine IGF-I gene revealed three banding patterns (genotypes) named as A/A, A/G and G/G. The frequencies of the observed genotypes were 0/52,0/42,0/06, respectively. Allele frequencies were 0/73,0/27 for A,G. The most frequent allele and genotype in the 'Makoei' sheep breed were 0/73 and 0/52 for allele A and genotype AA, respectively. Observed heterozygosity (Hobs) value was 0/3942. The observed distribution of genotypes was not different than the distribution expected under the assumption of Hardy-Weinberg equilibrium. These results confirmed the potential usefulness of IGF-1 gene in marker-assisted selection programs for sheep breeding.
