Coat Color Is the Genetically Determined Selection Trait in Horses (Equus caballus)

Abstract Currently, horse coat color is widely considered a key parameter influencing the economic value of horses. Advances in equine coat color genetics have attracted considerable attention among horse breeders. Coat color plays a crucial role in the identification and selection of horse breeds. Differences in coat color among different horse populations are a significant focus of genetic and breeding research. The range of coat colors is primarily determined by the type, concentration, and distribution of two melanin pigments, with the balance between eumelanin and pheomelanin, regulated by a complex multi-genetic system. Advances in genomic and sequencing technologies have identified several candidate genes that influence equine coat color, thereby clarifying the genetic basis of these diverse phenotypes. This review briefly presents the classification of coat colors in horses, as well as the regulatory roles of several key candidate genes, MC1R, ASIP, KIT, EDNRB, Cream, STX17, and TRPM1, in coat color variation. Over the past decades, many alleles affecting coat color in horses have been described. Some of these mutations are benign and aesthetically pleasing, while others have negative health effects (blindness, deafness, and mortality).