Association of single nucleotide polymorphisms in IGF-I, IGF-II and IGFBP-II with production traits in breeder hens of Mazandaran native fowls breeding station

The purpose of this study was to detect the polymorphism in IGF-I, IGF-II and IGFBP-II marker loci and their association with body weight at 8 weeks, average egg weight and total number of eggs laid during first 12 weeks after flocks maturity in breeder hens of native fowls. Blood samples were collected randomly from 160 individuals and genomic DNA was extracted using modified salting out method. A set of specific primer pairs were used for amplification of target genomic DNA at each marker loci and polymorphisms were detected using PCR-RFLP method. For IGF-I and IGFBP-II marker loci, allele B was the most frequent allele and ranged from 0.61 to 0.63 while, allele A was identified as a dominant allele in IGF-I marker site due to the highest frequency (0.57). The frequency of AA homozygous genotype was the lowest among all marker loci (0.08), whereas, AB genotype showed the highest frequency (0.61). Analysis of phenotypic data showed that the average egg weight and total number of eggs laid during first 12 weeks after flocks maturity were significantly affected by IGF-II and IGF-I marker loci respectively. No significant associations were observed between IGFBP-II genotypes and production traits. Comparison between detected alleles in the present study with reported allele by other research groups revealed a new allelic pattern for the analyzed marker loci in breeder hens of Mazandaran native fowls breeding station