Insulin-like growth factors are crucial in cellular growth, differentiation, and reproduction by mediating many of the actions of growth hormone in chickens. To determine whether insulin-like growth factors genes (IGFs) are associated with important economic traits in chicken or not, we herein analyzed the association between two single nucleotide polymorphisms (SNPs) within IGF1 and IGF2 and twenty-seven growth, body measurement, carcass, and reproduction traits in two Chinese native breeds, i.e., Beijing You and Silkies. With marker-trait association analysis, we found that SNP IGF1-PstI, within the 5' flanking region of IGF1, was significantly associated with body weight at 8 (BW8), 10 (BW10), and 13 (BW13) wk of age; and shank length (SL13) and shank circumference (SC13) at 13 wk of age in Silkie population (P < 0.05). The SNP IGF2-MspI within the exon2 of IGF2 showed a significant association with body weight (BW17) and carcass weight (CW17) at 17 wk of age in Beijing You population (P < 0.05). Our findings implied that the SNPs within IGF1 and IGF2 genes could be in linkage disequilibrium with the actual causative mutations that affect growth and carcass traits.
