Polymorphisms in candidate genes for athletic performance in Thoroughbred and Saddlebred horses

Abstract

The exports of athletic horses have increased and the techniques of genetic breeding aiming better athletic performance have been targeted by the breeders. The study of the muscle physiology associated with animal breeding techniques can provide knowledge to improve equine breeds, though environmental factors can interfere in the performance. The different types of training applied to athletic horses can change the physiological processes, such as the acid/base homeostasis mechanisms. The adenosine triphosphate (ATP) is the main fuel provided to muscle contraction. One of the ATP production pathways is the anaerobic glycolysis that has as final product lactate and hydrogen, and both are responsible for fatigue and muscular pain. Multiple genes are responsible for the variations in physiology and, consequently, in the performance of the animals. PDK4 gene is directly involved in the process of production of ATP because it regulates the assembly of the pyruvate dehydrogenase complex (PDC). Monocarboxylate transporter isoform 1 (MCT1) and its ancillary protein CD147, located on muscle and erythrocytes membrane, transport H+ and lactate ions from the plasma into the red blood cells, maintaining acid/base balance and retarding systemic acidosis and muscular fatigue. DMRT3 gene is involved in the coordination of the locomotor system that controls the movements of the members. Thus, considering the effects of DNA polymorphisms on phenotypes, this study aims to identify polymorphisms in MCT1, CD147, PDK4, and DMRT3 genes and check if there is any association between the polymorphisms and the breeds Thoroughbred and Saddlebred, and consequently, between their respective athletic skills. (AU)