GENETIC CHARACTERIZATION OF MYOSTATIN (MSTN) GENE AND ITS EFFECT ON LINEAR BODY MEASUREMENTS OF MUTURU CATTLE BREED

Abstract

ABSTRACT Myostatin (MSTN), a member of the transforming growth factor-β family is a negative regulator of muscle mass. This study was conducted to investigate Myostatin (MSTN) gene polymorphism in exon 1 and its effect on linear body measurements of Muturu cattle breed. Muturu cattle is characterised by a compacted body with good meat quality. A total of 26 animals between age 2 to 12 years were used in this study. 1ml of blood was collected from each cattle and DNA was extracted using Zymo research quick DNA mini prep kit following the manufacturer’s protocol. Data were collected on linear body measurements and were subjected to analysis using General Linear Model of SAS version 9.2. Polymerase chain reaction products of the MSTN gene were amplified and sequenced. The resulting sequences were edited using BIOEDIT and aligned with bovine MSTN of Bos taurus (GenBank Acc. No. AF320998.1) using MEGA 6.0 software. NCBI BLAST software was used to retrieve other cattle sequences and a phylogenetic tree was plotted showing the relationship between Muturu consensus sequence and the other cattle breeds. The sequence information revealed 10 single nucleotide polymorphisms (SNPs) in the MSTN gene that showed genetic variation with 3 synonymous mutations and 7 nonsynonymous mutations. The heterozygosity estimates indicates that all SNPs had low diversity. The allele frequencies for 186T>A, 218C>T, 414T>G, 418A>G, 459A>C, 496G>C were the highest with a value of 0.96. The Polymorphic information content ranged from 0.070 to 0.292. Eight haplotypes were identified in exon 1 with a high haplotype diversity and low nucleotide diversity. All tests of neutrality at exon 1 showed that there was an excess of rare alleles in the Muturu population. The animals were separated into three age groups and the association analysis showed that SNP 345 G > C was significantly (p < 0.05) associated with height at wither, heart girth at 4 to 8 years, rump height and tail length at 2 to 4 years. SNP 481 A > C was significantly associated with muzzle circumference and hock circumference (p < 0.05) at 4 to 8 years. It was concluded that genetic variations exist in exon 1 of MSTN gene making it a candidate marker for genetic improvement. However, there is need to validate the association study with a larger population size.