An Introduction to
Genomic Selection is a technique that has been used in the cattle industry for many years, and has helped to breed selectively for increased milk production in dairy cows.
Selection decisions are based on genomic breeding values (GEBV), which are calculated by first observing a large reference population with known phenotypes and genotypes. This is used to compute an equation to predict genomic estimated breeding values on selection candidates. The prediction equation combines all marker genotypes (X) with their effect (x) on each trait in the breeding goal to predict GEBVs of each selection candidate. GEBVs are then used to select the best parents for the next generation.
These breeding values can be applied to a wide range of breeding goals, but in a very focused manner. In particular health and soundness issues as well as genetic defects seem to be very practical applications for the technology. Large amounts of accurate data are required so it is an area that will show most progress when there is close cooperation between the scientific community and breed organizations.
One of the challenges in sport horse breeding is the length of time that elapses between an original breeding decision or mating, and the resulting horse reaching his or her peak performance around ten years later.
Genomic selection in future horse breeding has the potential to provide reliable information on which breeders can base their choices while reducing these long generation intervals.
Successes have already been observed in thoroughbred breeding, where the “speed gene”, has been identified. This technique is now being studied more closely to consider how it can be applied to drive the evolution of sport horse breeding.
However, one of the core differences between success in horse racing and in other equestrian disciplines is the complexity and potential interactivity of different traits. While success in horse racing is easily identified as the ability to run fastest, in all three Olympic disciplines, a wide range of abilities are required and need to be carefully balanced.