The role of myostatin on the conformation and gaits of the Icelandic horse

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 (pp=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.