DMRT3 is associated with gait type in Mangalarga Marchador horses, but does not control gait ability.

The article investigates the relationship between the DMRT3 gene mutation and the unique gait found in the Mangalarga Marchador horse breed. The results show that while the gene mutation is associated with the horse’s gait type, it does not solely control the ability to perform lateral patterned gaits.

Research Methodology

• The researchers examined 81 Mangalarga Marchador (MM) horse samples. DNA was extracted from hair bulbs and then tested for the DMRT3 gene mutation, using a new way of Restriction Fragment Length Polymorphism (RFLP).
• These horses were phenotypically categorized by their gait type (batida or picada) as recorded by the Brazilian Mangalarga Marchador Breeders Association (ABCCMM).
• An advanced statistical analysis was carried out using the plink toolset to understand the relationship between the horse’s gait and the presence of DMRT3 mutation.

Findings and Interpretations

• The results of statistical analysis revealed that there was a significant association between the gait type and DMRT3 mutation.
• Deviation from Hardy-Weinberg equilibrium indicates that there is a selective pressure existing for gait type which is altering allele frequencies in this breed. Alleles are different forms of a gene that are found at the same place on a chromosome. Hardy-Weinberg equilibrium is a principle stating that both allele and genotype frequencies in a population remain constant, unless specific influencing factors are introduced. In this case, the influencing factor is likely the DMRT3 mutation.
• Though the polymorphism (DMRT3 mutation here) can be useful for genotype-assisted selection for gait type within this breed, it is not the sole agent responsible for the lateral gait pattern since both batida and picada MM horses, irrespective of their DMRT3 mutation status, can perform lateral gaits.

Significance and Implications

• The study suggests that the DMRT3 mutation does not control the ability to perform lateral patterned gaits in horses. It contradicts the findings of a previous study by Andersson and colleagues in 2012, who claimed that this gene mutation controls gait.
• Despite not being the controlling factor, the DMRT3 mutation does show a significant association with gait type, and could be helpful in selecting accordingly for breeding purposes.
• The study further stresses that more factors or loci may be involved in determining the lateral gait pattern in Mangalarga Marchador horses.