Association of polymorphisms of IGF1 promoter with growth and fertility performance in PB1 parent line of broiler chicken variety

Blood samples from 180 birds pertaining to a single generation of PB1 parent line were collected for present study. The birds were raised under standard management and different growth variables were recorded up to 20 weeks of age. Age at first egg and egg production till 40 weeks of age was recorded in females. PCR-RFLP analysis was used to screen individuals with polymorphisms in IGF1 promoter region and three genotypes AA, AC and CC were identified at frequencies of 0.79, 0.18 and 0.03, respectively. CC homozygotes were lower with respect to their performance in growth and fertility traits. Sequencing results of both alleles revealed T244G transversion mutation in the C allele. Gene regulation analysis confirmed that such transversion resulted in non-binding of Oct-1 transcription factor at 241 to 250 bp in C allele, causing down regulation of the gene. The mutations in the promoter sequence affected the transcriptional gene regulation affecting growth and fertility performance.