Equine performance genes and the future of doping in horseracing.

A horse's success on the racetrack is determined by genetics, training and nutrition, and their translation into physical traits such as speed, endurance and muscle strength. Advances in genetic technologies are slowly explaining the roles of specific genes in equine performance, and offering new insights into the development of novel therapies for diseases and musculoskeletal injuries that cause early retirement of many racehorses. Gene therapy approaches may also soon provide new means to artificially enhance the physical performance of racehorses. Gene doping, the misuse of gene therapies for performance enhancement, is predicted to be the next phase of doping faced by horseracing. The risk of gene doping to human sports has been recognised for almost 15 years, and the introduction of the first gene doping detection tests for doping control in human athletes is imminent. Gene doping is also a threat to horseracing, but there are currently no methods to detect it. Efficient and accurate detection methods need to be developed to deter those looking to use gene doping in horses and to maintain the integrity of the sport. Methods developed for human athletes could offer an avenue for detection in racehorses. Development of an equine equivalent test will first require identification of equine genes that will likely be targeted by gene doping attempts. This review focuses on genes that have been linked to athletic performance in horses and, therefore, could be targeted for genetic manipulation. The risks associated with gene doping and approaches to detect gene doping are also discussed.