Single nucleotide polymorphism in insulin like growth factor-1 (IGF-1) gene and its effect on economic traits in Indian colored broilers

Insulin like growth factors -1 (IGF-I), one of the important candidate of IGF system is primarily a paracrine or an autocrine growth factor required for cell proliferation in many tissues. An SNP (A → C) at 570 bp position in promoter region IGF-I, was reported to be associated with body weight and average daily gain in broilers. Present study was undertaken to detect the IGF-1 SNP, find out its polymorphism and association with economic traits in the Colored Synthetic Male line (CSML) of broiler line maintained at Experimental Broiler Farm (EBF) of the institute. Genomic DNA was isolated form 100 CSML birds and a fragment of 813 bp of IGF-1 gene was amplified using specific primers in a PCR reaction. Hinf I PCR-RFLP of amplified product revealed two alleles A (378, 244 and 191 bp size bands) and B (622 and 191 bp size band) and three genotypes viz. AA, AB and BB on PAGE. The frequency of allele A and B were 0.83 and 0.17, respectively. However, the frequency of AA genotype was highest (0.70) followed by AB (0.27) and BB (0.03). The sequence analysis of both the homozygotes (AA and BB) revealed that the SNP (A’!C) was at 570 bp in the promoter region and nucleotide ‘A’ at and ‘C’ was present at respective position in sequences of genotype AA and BB respectively. The analysis further revealed significant association of IGF-1 SNP (570A→C) with growth parameters showed viz. body weight at 3^rd, 4^th, and 5^th weeks of age; confirmation and carcass traits at 5 week of age.