Characterization of the Sarcidano Horse Coat Color Genes

Coloration in Equine: Overview of Candidate Genes Associated with Coat Color Phenotypes

Variation in coat color among equids has attracted significant interest in genetics and breeding research. The range of colors is primarily determined by the type, concentration, and distribution of melanin pigments, with the balance between eumelanin and pheomelanin influenced by numerous genetic factors. Advances in genomic and sequencing technologies have enabled the identification of several candidate genes that influence coat color, thereby clarifying the genetic basis of these diverse phenotypes. In this review, we concisely categorize coat coloration in horses and donkeys, focusing on the biosynthesis and types of melanin involved in pigmentation. Moreover, we highlight the regulatory roles of some key candidate genes, such as MC1R, TYR, MITF, ASIP, and KIT, in coat color variation. Moreover, the review explores how coat color relates to selective breeding and specific equine diseases, offering valuable insights for developing breeding strategies that enhance both the esthetic and health aspects of equine species.

Discrepancies between Genetic and Visual Coat Color Assignment in Sarcidano Horse

This study aimed to evaluate the discrepancies between genetic and visual coat color assignment in the Sarcidano Horse and to elucidate potential reasons. Individual DNA from 90 Sarcidano Horses was used for genetic assignment of coat color to explore the correspondence with individual forms containing phenotypical traits. The MC1R exon 1 and ASIP exon 3 have been genotyped and sequenced to obtain a picture of the coat color distribution in this breed. Surprisingly, once we compared the genetic results with the individual forms reporting the phenotypic data for each subject, a certain degree of non-correspondence between the phenotypic and genetic data in relation to coat color emerged. From the genetic analysis, Chestnuts (n = 58) resulted the most common Sarcidano Horse (n = 58), followed by a quite large number of Blacks (n = 28) and a very small number of Bays (n = 4), whereas phenotypic distribution resulted in 38 Chestnuts, 40 Bays, only 2 Blacks, and 10 Grays (without the possibility of recognizing the true color they carried). Chestnut resulted a very representative coat color, while many horses that visually identified as Bays were genetically Blacks. This discrepancy, that could be due to a variety of individual and external factors, including age, time of year, living situation and dietary condition, suggesting the importance of accurate coat color identification to ensure adequate features registration and reliable prediction of offspring's coat color.