Morphometric variation and muscle growth genes polymorphism between two indigenous sheep populations

Abstract

Ethiopia owns significant sheep genetic resources, but their potential for meat production remains underutilized. Hence, there is a need to characterize their morphometric traits and muscle growth gene polymorphisms of sheep populations. The study aimed to identify the morphometric variation and genetic polymorphism of the Callipyge (CLPG) and Myostatin (MSTN) genes in two sheep populations. Sheep from the North and West Shewa zones of Oromia National Regional State were purposively selected, and morphometric data (body weight and linear body measurements) were collected from 540 sheep (270 from each zone). Blood samples were collected from 180 sheep (90 from each zone) using vacutainer tubes with EDTA for genotyping at the CLPG and MSTN loci. DNA extraction and quality assessment were carried out using salting out procedure and gel electrophoresis, respectively. Polymerase chain reaction amplification was performed with gene specific primers. The amplified products were digested with restriction enzymes and visualized using gel electrophoresis. Morphometric data were analyzed using SPSS, while Popegen32 software was used for analysis of genotype data. Significant variation (p < 0.05) was observed in body weight and linear body measurements and morphometric indices between the two sheep populations. West Shewa sheep showed higher values in most trait and indices considered. Two alleles (A and G) and three genotypes (AA, AG, GG) were detected at the CLPG locus, and two alleles (M and m) with three genotypes (MM, Mm, mm) were identified at the MSTN locus in both populations. In North Shewa sheep, allele frequencies for A and G were equal (0.5), whereas allele G (0.57) was more frequent than allele A (0.43) in West Shewa. For the MSTN gene, the allele frequency of m (0.55) was higher than M (0.45) in North Shewa, while allele M (0.6) was more frequent than allele m (0.4) in West Shewa. Both genes were polymorphic in both populations, with expected heterozygosity and the number of alleles being comparable. The study revealed morphometric variation and polymorphism at the CLPG and MSTN loci in two sheep populations. Further studies with larger sample sizes and different ecotype of sheep populations are needed to validate the current findings and explore the potential of these genes as genetic markers for meat production.