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

SIMPLE SUMMARY: Myostatin is a protein which plays a key role in the regulation and differentiation of cells. The encoding gene, MSTN, and its mutations have been studied in cattle because of the association with increased muscle masses. In horses, some polymorphisms at MSTN have favorable effects on sport performance, as evidenced for the Thoroughbred breed. The Anglo-Arabian horse is a very common breed in many Mediterranean countries because of its extreme adaptability, but genetic investigations are rare in the literature. The present study evidenced the relatively high variability of this breed at MSTN. Many phenotypic effects, such as sex and genealogy, affected the results but, overall, the same polymorphic sites already reported for Thoroughbred horses affected race performances also in Anglo-Arabians. 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.