Effect of Single Nucleotide Polymorphisms in IGF-1R Gene on Growth Rate Traits in Makooei Sheep

Insulin-like growth factor 1 receptor (IGF-1R) is a main receptor of IGFs family which plays a critical role in the postnatal growth and skeletal growth in many species. However, there are few reports of IGF-1R gene structure and its effects on growth traits in sheep. The objectives of this study were detection of IGF-1R polymorphisms and assessment of their associations with growth traits in Iranian Makooei Sheep. Hence, 200 Makooei lambs were genotyped through polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP). The studied traits were birth weight (BW), weaning weight (WW), 6 months weight (6MW), average daily gains from birth to 3 months (ADG0-3), from 3 months to 6 months (ADG3-6), from birth to 6 months (ADG0-6) and corresponding Kleiber ratios (KR0-3, KR3-6, KR0-6).For this genetic position, three types of banding patterns (AA, AB and BB) were identified with the frequencies of 0.69, 0.16 and 0.15, respectively. In this study, IGF-1R genotypes indicated the significant associations with 6MW, ADG0-6, KR0-3 (P<0.05) and ADG0-3 (P<0.01). In all of the significant traits, The A Agenotype was linked to the highest values, while the B Bgenotype was linked to the lowest values. The results of this study indicated that single nucleotide polymorphism (SNP) variation in IGF-1R gene can be used as a molecular marker for improving of growth traits in marker assisted selection programs in sheep.