Genotypic Frequency in Asian Native Chicken Populations and Gene Expression Using Insulin-like Growth Factor 1 (IGF1) Gene Promoter Polymorphism

Abstract

A single nucleotide polymorphism (SNP) site, alleles and within promoter region of gene ( ) showed significant association with chicken growth, body composition and skeletal traits. In the present study, we performed genotyping of this SNP in Asian native chicken populations, layer and broiler populations using PCR-RFLP and comparison of gene expression level and growth traits among the SNP genotypes. By the PCR-RFLP, allele frequency was estimated to be within the range of .. in Asian native chicken populations, .. in eight layer stocks and . . in two broiler stocks examined in this study. In all chicken populations, the observed number of each SNP genotype was in good agreement with the Hardy-Weinberg expectations. Body weight (BW), average daily gain (ADG), growth rate and gene expression level in three-week liver were compared among three SNP genotypes obtained by crossing. The rankings of each genotype with respect to BW, ADG and growth rate were and statistical significance ( . ) was found within and in BW and ADG. The rankings of each genotype with respect to the gene expression level wasAlthough we could not find statistically significant di erence among the genotypes in the growth rate and the gene expression level, the mean values of were lower than those of in all traits.: chicken, gene expression, insulin-like growth factor , liver ). A single nucleotide polymorphism (SNP) ( ) within the promoter was significantly associated Insulin-like growth factor (IGF) system plays a pivotal with chicken growth, body composition and skeletal traits role in regulation of embryonic and postnatal development (Amills ; Zhou ; Bennet in vertebrates (McMurtry ; Dupont and ). Asian native chicken populations are low producHolzenberger, ). IGFs stimulate hepatic glycogen, tivity such as slow growth rate and low egg production, increased DNA synthesis and tissue growth in chicken although they have desirable genetic characteristics for an (McMurtry ). Insulin-like growth factor excellent taste in their products, acclimation to heat and (IGF ) can act its functions through endocrine, paracrine resistance to diseases (Nishibori ). Therefore, and autocrine pathways (Stewart and Rotwein, ). genotyping of the SNP associated with several traits The highest expression of gene was observed in in various Asian native chicken populations may lead to liver of normal chicken but no expression was found in their genetic evaluation and improvement of their producthat of dwarf chicken liver (Tanaka ). The tivity. expression of hepatic mRNA and circulating IGF In the present study, we performed genotyping of the concentration were greater in chickens selected for high SNP within the promoter in various chicken populagrowth rate than in low growth rate chickens (Beccavin tions including Asian native chickens and comparison of the gene expression level among three SNP genotypes.

Insulin-like growth factor-I gene polymorphism and its association with growth and slaughter characteristics in broiler chickens

“…The CC homozygous genotype was not found at all in the broiler population. This confirms a study by Moe et al (2009) in which also no CC genotype was found in Cobb broilers.…”

“…In this study, we investigated the genotypic and allelic frequencies of SNP within the chicken IGF1 gene promoter region in two broiler populations. The allele frequencies of IGF1-SNP1 were in Hardy-Weinberg equilibrium, suggesting that the IGF1 polymorphism does not affect the fitness of birds (Moe et al 2009). In both commercial broiler lines, the allelic frequency of A was higher than that of the allele C. This result suggests that the broilers as chickens bred for high intensity growth, were high in distribution of allele A.…”

“…In both commercial broiler lines, the allelic frequency of A was higher than that of the allele C. This result suggests that the broilers as chickens bred for high intensity growth, were high in distribution of allele A. This can be explained as an effect of selection on growth traits because native and layer chicken populations showed a higher frequency of allele C than that of allele A (Moe et al 2009).…”

“…The Hinf I PCR-RFLP analysis showed fragments of 622, 378, 244 and 191, and 378, 244, and 191 bp. Allele A is characterized by three fragments of sizes 378, 244 and 191 bp and allele C is given by the length of fragments 622 and 191 bp (Moe et al 2009). The genotypic and allelic frequencies of the IGF1 gene in the two broiler populations are given in Table 1.…”

“…In the chicken, this is a functional candidate gene for growth, body composition and metabolism (Zhou et al 2005). The chicken IGF1 polymorphism has been reported in previous studies (Nagaraja et al 2000, Amills et al 2003, Zhou et al 2005, Bennett et al 2006, Moe et al 2009 but no report exists on the association of IGF1-SNP with body composition traits in the Ross 308 broiler line. Fig.…”