Effect of IGF-I gene polymorphism on various economic traits of synthetic White Leghorn

250 synthetic White Leghorn pullets were housed at 16 weeks of age in individual California cage system and various principal production traits were recorded on individual birds. On the basis of feed consumption and egg production during 51–60 weeks, these birds were categorized as, High feed consumption and High egg production (HH), Low feed consumption and High egg production (LH), High feed consumption and Low egg production (HL) and Low feed consumption and Low egg production (LL). From each group, 10 birds were utilized for the present study. The, genomic DNA was extracted from 40 birds by John's method with some modification. Chicken gene specific primers were used for amplification of IGF-I gene and amplicon was digested with Hinf-I for RFLP analysis. Polymorphic patterns were found in IGF-I gene. Gene (A and B) and Genotypic frequencies of AA, BB and AB genotypes were estimated. Significant (P<0.05) difference was observed between IGF-I genotypes and EN51–60. AB genotype had significantly (P<0.05) higher EN51–60 as compared to AA and BB genotypes, suggesting in heterozygous condition birds had given more egg production. In IGF-I group effect was found to be significant for EN51–60, TEN72, FC51–60/egg, BW40 and EW (at 32, 64, 72 weeks). The present study revealed the strong association of different RFLP patterns with various economic traits.