SynchroGait (DMRT3-related)

The SynchroGait mutation is a variant in the DMRT3 gene which is involved in leg coordination, and has also been known as the “Gait keeper” mutation. Research shows that the variant occurred around the time of domestication and is therefore found in many breeds worldwide.

One of the best known of these is the Icelandic horse, where animals with one or two copies of the variant may have the ability to perform alternate gaits, like the famous tölt or pace. A normal, three gaited horse (walk, trot, gallop) has the C/C genotype, while Icelandic horses with the C/A genotype have the genetic potential to be trained in the tölt (4 gaited) and those with the A/A genotype have the genetic potential to be trained to the pace (5 gaited). These horses may be less coordinated with gait changes between the trot and gallop.

The variants have different influences in different breeds and gait types. Current research indicates that there are other, as of yet unidentified variants in other genes that influence the quality of the gaits, particularly in other breeds. For example, harness-racing Standardbreds with one copy of the variant (C/A) may be able to trot faster without switching into a gallop than their normal (C/C) counterparts. Horses with two copies of the variant (A/A) will have the capacity to pace.

In other gaited breeds, the SynchroGait mutation may allow for four-beat ambling gaits, although other, as yet unidentified, genetic variants also influence the quality of those gaits.

In traditionally non-gaited breeds, having one or two copies of the mutation can result in horses having less clean gait changes, or difficulty transitioning from the trot to the canter. Foals with the variant may take longer to develop leg coordination; this should not be mistaken for ataxia.

Relevant tests

• P516