Comparison of DMRT3 genotypes among American Saddlebred horses with reference to gait.

The research attempted to examine the association between different genotypes of the DMRT3 gene in American Saddlebred horses and the exhibition of a 4-beat gait. However, the outcome indicated no significant link between the DMRT3 alleles and the decision to train horses as 5-gaited.

Background

• The study is centered around the American Saddlebred horses (ASHs) and how their gait may or may not be influenced by the DMRT3 gene. This gene is known to affect the pattern of locomotion in various horse breeds, particularly enabling a pacing gait and an association with performance in diverse breeds.
• Particularly, owners often train ASHs to perform the 4-beat gaits called rack and slow gait, which are not naturally occurring gaits, but similar to the ambling gaits that are believed to be associated with variation in the DMRT3 gene.
• This research was designed to explore any relation, or lack thereof, between the Ch23:g.22999655C>A single-nucleotide polymorphism (SNP) of the DMRT3 gene, which results in a premature stop codon (DMRT3_Ser301STOP), and the tendency for ASHs to exhibit the 5-gait pattern.

Methodology

• The researchers used horse show records to identify ASHs that were trained to perform as 5-gaited horses, and compared them with other Saddlebreds.
• They analyzed the prevalence of the A allele of the Ch23:g.22999655C>A SNP in DMRT3. Genomic DNA genotyping was done using a PCR-RFLP (Polymerase Chain Reaction-Restriction Fragment Length Polymorphism) technique. The sample size involved was 55 5-gaited ASHs, 64 3-gaited or harness ASHs, and 128 ASHs that were not shown.

Results and Conclusion

• The results revealed no significant differences in the frequencies of the Ch23:g.22999655C>A SNP of DMRT3 when comparing 5-gaited ASHs with other ASHs. The P-value obtained from the comparison was greater than 0.22, which implies that there is no statistically significant difference between these groups.
• This suggests that the choice of breeders to train and showcase ASHs as 5-gaited horses is not influenced by DMRT3 alleles. Hence, the study concluded that the genetic difference of DMRT3 might not play a role in the gait training decisions for ASHs.