Evaluation of Single Nucleotide Polymorphism and Genetic Diversity at the Myostatin gene Locus in Indigenous and Locally Adapted Exotic Turkey breeds in Nigeria

Abstract

This research was carried out to characterize single nucleotide polymorphism at the myostatin gene locus in indigenous and Nigerian locally adapted exotic turkeys. A total of 220-day-old poults comprising 120 local and 100 locally adapted exotic turkeys were sourced from reputable hatchery and were managed for 20 weeks under intensive management system. Blood samples were collected from 70 turkeys each form the two breeds via the brachial vein into Ethylene Diamine Tetra Acetic Acid (EDTA) bottles for DNA extraction and amplification of target regions using commercially available kits when the birds were 8 weeks. Genomic regions containing exon 1 and 2 of MSTN gene including their surrounding introns were sequenced and analyzed using BioEdit, Codon Code Aligner, DnaSP and MEGA software. Codon-based test was also performed to estimate the ratio of non-synonymous substitutions (dN) to synonymous substitutions (dS). Results from our study showed that both local and exotic turkey breeds had one non-synonymous single nucleotide polymorphism (SNP) (248 G>A) in exon 1 while SNP variant 333 G>A was detected only in exon 2 of exotic turkey. In intron 1, a total of 3 SNPs in local turkey and 2 SNPs in exotic turkey were detected. Intron 2 also revealed 4 and 3 SNPs in local and exotic turkeys respectively. Genetic diversity indices showed that local turkey had higher haplotype diversity at intron 1 (75 %) and intron 2 (84 %) while haplotype diversity of 20 % was estimated at exon 2 in exotic turkey. Our Codon-based test of selection showed dN/dS ratio of <1 (purifying selection) at G248A SNP loci, suggested a possible role of this non-synonymous SNP variant on growth performance. We recommend a population-based study to investigate the effect of this non-synonymous SNP G248A on growth and morpho-structural traits for breed improvement and conservation of our locally adapted turkey populations.