Polymorphism of IGF-1 Promoter and the UTR Regions of Nigerian Locally Adapted Chickens

Abstract

Growth traits which are controlled by many genes are important economic traits in the poultry industry. The insulin-like growth factor gene (IGF-I) is a candidate gene for growth, body composition and metabolism, skeletal characteristics and growth of adipose tissue and fat deposition in chickens. The promoter and the untranslated region (UTR) of Insulin growth factor I gene was investigated to identify single nucleotide polymorphism, their genetic diversity and evolutionary relationship among six locally adapted strains of chicken in Nigerian. In this study, blood samples were collected and a specific primer pair was designed for amplifying a fragment of IGF-1 gene using polymerase chain reaction (PCR). The PCR products were sequenced while nucleotide sequences generated were edited and aligned using Mega v6.0 software. Nucleotide polymorphisms within each strain were detected using DNAsp v5 software. A total of eight SNPs were identified across the populations studied which were different already published SNPs associated with growth rate in chicken. Naked Neck chicken showed the highest genetic diversity from others with the highest number of polymorphic site, haplotype diversity and nucleotide diversity while the least were observed in Frizzle Feathered chicken. The phylogenic tree showed that small genetic differentiation exists among the chicken populations in this region. We reported the first genetic data from the promoter and the UTR regions of IGF-I gene in Nigerian native chickens and established baseline information regarding  variation in insulin growth factor I which should inform continued investigations into production potentials of these chickens and formulation of appropriate selection and breeding programs

Keywords: SNPs, Genetic diversity, IGF-1, Chicken