Association of the polymorphism in the 5â flanking region of the ovine IGF-Igene with growth and development traits in Makuisheepof Iran

The insulin-like growth factor 1 (IGF-I) gene has been described in several studies as a candidate gene for growth.Thispreliminary study attempts to identify associations between growth traits and genetic polymorphisms at the 5’ flanking region IGF-I in Makui sheep. DNA samples from100Makuisheep,anindigenous Iranian breed,wereevaluated in the research. Polymerase chain reaction-single strand conformation polymorphism (PCRSSCP) analysis of the 5’ flanking region (Exon1) of the ovine revealed that the IGF-I gene had the following three banding patterns (genotypes); A/A, A/G and G/G. The evaluation of an association between these SSCP patterns with birth weight (BW), weaning weight (WW),six month weight(SW),nine month weight (9W), average daily gain from birth to weaning (GBW), weaning to six months (GWS), from six months to nine months (GSN), from nine months to yearling weight(GNY) and developmenttraits in oneyear demonstrated a positive effect of the pattern (Genotype) A/G with GBW and weaning weight (WW)andsix month weight(SW). The pattern (Genotype) A/Ademonstrated superior birth weight when compared to those with other gene patterns.GBW, GNY and biometric or developmenttraits were influenced significantly by sex (p0.05).These results demonstrated that IGF-I gene could be a genetic locus, or linked to a major gene that significantly affects growth and the afore-mentioned economic traits in sheep.