Author:

Abstract:

The influence of myostatin (MSTN) on conformation, an important selection criterion in many horse breeds, has only recently come to light. Although conformation is considered a complex trait influenced by multiple genes, recent studies have shown that MSTN not only influences the morphological type of an individual, but also the individual’s performance. Through its role as a repressor in the development and regulation of skeletal muscle mass, MSTN is a major gene of interest. This is a first study looking into its influence on conformation and riding ability of the Icelandic horse, a breed known for its robust and compact conformation, and additional gaits, tölt and pace. Three SNPs (g.65868604G>T, g.66493737C>T and g.66495826A>G) within MSTN were analyzed in 195 Icelandic horses and their association to official estimated breeding values for 16 traits was evaluated. Significant associations (p<0.05) were found with several conformation traits such as neck/withers/shoulders, hooves, leg stance and total conformation. Furthermore, there was an indication that myostatin possibly influences the performance of the ambling trait tölt, a gait unique to gaited horse breeds (p=0.07). This study showed that MSTN plays a role in the complex background of breed-specific conformation traits and has a possible influence on tölt, a unique and highly selected trait within this breed. Further analysis will help to decipher the specific pathway by which MSTN influences these traits.