CHICKEN GROWTH HORMONE GENE POLYMORPHISM OF SELECTED CHICKEN BREEDS IN NIGERIA

Abstract

The study was carried out to investigate polymorphism at the Chicken Growth Hormone (cGH) gene of selected chicken breeds (Fulani ecotype, Noiler, FUNAAB Alpha, Frizzled feathered and Cobb 500 was used as the reference breed) in Nigeria. Genomic DNA was extracted from blood samples collected from 50 birds. Amplification of specific DNA fragments at intron 3 of the cGH gene yielded a product size of 715 bp and this was used to analyze for polymorphism using Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) technique. Banding patterns of the gene investigated, revealed the occurrence of three RFLP variants: TT, CT and CC with genotype frequencies of 0.449, 0.245 and 0.306, respectively. The allele frequencies of the T and C alleles were 0.469 and 0.531, respectively indicating that the C allele was predominant. Chi-square test revealed that the chicken population investigated was in Hardy-Weinberg equilibrium. Forty seven (47) Single Nucleotide Variant (SNV) was observed at the intron 3 of the cGH gene for selected chicken breeds studied. Six numbers of Single Nucleotide Polymorphism (SNPs) were discovered at exons having four missense variant (locus 4036303, 4036384 and 4036921/4036922) with (8.51 %), two synomous variant (locus 4036325/4036326, 4036381) with (4.26%), one frame shift variant (locus 4036303) with (2.13 %) and one splic region variant (locus 4036384) with (2.13 %), while the rest were at the introns with (87.23 %). It was concluded that, the presence of observed genetic variations in the cGH gene, could be exploited because of its association with economically important traits.