Polymorphisms at Myostatin Gene (MSTN) and the Associations with Sport Performances in Anglo-Arabian Racehorses

Abstract

One hundred and eighty Anglo-Arabian horses running 1239 races were sampled for the present study. DNA was extracted from the blood and myostatin gene, MSTN, was genotyped. Moreover, prizes won and places were achieved for the 1239 races to perform association analyses between the different genotypes and sport traits. Two SNPs already reported in previous studies regarding the Thoroughbred breed, rs69472472 and rs397152648, were revealed as polymorphic. The linkage disequilibrium analysis investigating the haplotype structure of MSTN did not evidence any association block. Polymorphism at SNP rs397152648, previously known as g.66493737 T>C, significantly influenced sport traits, with heterozygous horses TC showing better results than homozygotes TT. The portion of variance due to the random effect of the individual animal, and the other phenotypic effects of sex, percentage of Arabian blood and race distance, computed together with the genotype at MSTN in the statistical models, exerted a significant influence. Hence, this information is useful to improve knowledge of the genetic profile of Anglo-Arabian horses and a possible selection for better sport performance.

Genetic Association of MSTN Variant (18:66493737T>C) with Racing Performance & Muscle Development in Pakistani Horses

“…Many scientists reported that this variant is associated with the racing performance and muscle development among different breeds of horses. Preceding studies showed a significant difference in genotypic and allelic frequencies associated with racing performance in thoroughbred and Anglo-Arabian breeds horse population (3,10).…”

“…Function of this protein is to restrict the development and growth of muscle fibers. In recent studies, researchers found that the MSTN is linked to racing performance, growth of skeletal muscle and carcass quality traits in different species including livestock animals, dogs, and horses (4) Moreover, the Myostatin gene is a major determinant of racing performance because it also influences the proportion of fast twitch and slow twitch muscle fibers in horses (3,5,6).…”

“…MSTN gene encodes Myostatin protein, also known as GDF-8 (Growth differentiation factor 8) which belongs to TGF-β (transforming growth factor beta) family of growth and differentiation factor (2,3). Function of this protein is to restrict the development and growth of muscle fibers.…”

“…In horses, single nucleotide polymorphism (SNP) at region 18:66493737T>C (rs397152648) had been identified as a genetic marker to analyze the racing performance (7). From the previous genetic studies, the wild-type genotype (T/T) is linked to horse's stamina and muscle development, heterozygous (T/C) genotype horses give better performance in middle distance races whereas homozygous mutant type (C/C) horses are top performers, fast-paced and short-distance sprinters (3,8) Furthermore, the studies also suggested that fast twitch glycolytic, type II-B muscle fibers provide short bursts of power in horses. Hence, the C/C horses have best racing performance and to be considered as sprinters.…”

Comparison of Random Regression Models with Different Order Legendre Polynomials for Genetic Parameter Estimation on Race Completion Speed of Arabian Horses

“…Arabians are also highly appreciated as racehorses and earn considerable rewards throughout their gallop racing careers [ 4 , 8 ]. In addition, the Arabian horse breed is recognized as the leading breed in endurance competitions [ 9 ], but there was no evidence that this breed was genetically superior to other racehorse breeds [ 10 ]. Machmoum et al [ 11 ] argued that the genetic diversity of the Arabian horse breed decreases near the risk threshold, which should be considered in breeding studies.…”