The effect of the ‘Gait keeper’ mutation in the DMRT3 gene on gaiting ability in Icelandic horses.

The research paper examines how the ‘Gait keeper’ mutation in the DMRT3 gene impacts the gaiting ability in Icelandic horses, finding that this mutation contributes significantly to the ability to perform lateral gaits and favors speed in trot.

Background and Aim

• The research was primarily conducted to further understand the effects of the nonsense mutation affectionately referred to as ‘Gait keeper’, on the gait quality and speed of multigaited Icelandic horses.
• Researchers also aimed to observe how the frequencies of the A- and C- alleles, associated with the DMRT3 mutation have altered in the Icelandic horse population recently.

Methodology and Findings

• During the course of the study, it was discovered that horses with homozygosity for the DMRT3 nonsense mutation held a better ability to pace.
• The mutation also had a beneficial effect on the lateral gait tölt’s breeding field results shown by improved beat quality, speed, and suppleness.
• In contrast, horses with the CA genotype outperformed in walk, trot, canter, and gallop, showcasing better beat and suspension during trot and gallop.
• The researchers found that the AA genotype improves the coordination of ipsilateral legs, affecting the synchronized movement of the animal’s diagonal legs when compared with the coordination inherent in the CA genotype.

Changes in A- and C- Allele Frequencies

• The researcher noted a substantial increase in the A-allele frequency with a corresponding decrease in the C-allele frequency in recent decades.
• The A-allele’s estimated frequency was 0.94 in the Icelandic horse population in 2012.
• This shift in frequencies suggests that selective breeding focused on lateral gaits has altered the DMRT3 genotypes frequency, predicting a loss of the C-allele in the coming years.

Implications of the Study

• The research has shown that the ‘Gait keeper’ mutation has a substantial effect on a horse’s gaiting ability, having practical implications for the breeding and training of not only Icelandic horses, but also other gaited horse breeds.