Identification of Two Genetic Haplotypes Associated with the Roan Coat Color in the American Quarter Horse and Other Equine Breeds.

The research paper discusses the identification of two genetic types related to the roan coat color in the American Quarter Horse and other equine breeds.

Overview of Roan Coat Color

• The term ‘roan’ refers to a specific coat color in horses, characterized by white hair dispersed within an otherwise solid background color. This coloration is mainly seen on the body of the horse, while the head and legs usually have little to no white hairs.
• The genes responsible for this color have been traced to the KIT region of the equine genome in prior studies. However, using these genetic markers to identify the roan genotype in different horse breeds has yielded inconsistent results.

Identification of New Roan Allele

• In this study, researchers found an additional roan allele, RN2. When combined with another roan allele, RN1, identified in previous research, these two genetic types cover about 74% of roan horse cases, based on a sample of 257 roan horses.
• The presence of these two alleles represents about 188 horses out of the total sample.

Presence in Non-Roan Population

• The researchers found that these two alleles existed in less than 1% of the non-roan horse population studied, which consisted of 3,212 horses.
• Interestingly, the presence of these alleles was only found in horses with light coat color and dilution alleles — genetic variations that may potentially hide the roan phenotype (the physical manifestation of genetic traits).

Future Research

• The study suggests the need for further research to identify other alleles that may be responsible for additional variations in the roan coat color phenotype in horses.