Gaitedness is associated with the DMRT3 'Gait keeper' mutation in Morgan and American Curly horses

The nonsense mutation in the DMRT3 gene is known to affect locomotion pattern and gait ability in horses[1] and performance of Standardbred and Nordic trotters.[1, 2] The mutation (a change from cytosine, C, to adenine, A) has been found in all tested gaited breeds and in breeds used for harness racing, whereas it is absent in most of the three-gaited breeds, such as the Swedish Warmblood and Thoroughbreds.[3] Previous studies have shown that the mutation is strongly associated with horses' ability to perform alternate gaits.[1, 3, 4] In the study by Promerová etal.,[3] breeds with a frequency of the mutation at 50% or higher were classified as either gaited or breeds used for harness racing. There are many different types of alternate gaits, for example foxtrot, running walk, tölt and pace.[3] In this study, we investigated if there is a connection between the genotype in DMRT3 and gaitedness in Morgan and American Curly horses. Previous study showed that the frequency of the mutated A allele in these breeds was 14.0% and 16.7% respectively.[3]