Pedigree tracing to determine the origin of the golden coat phenotype within the golden American saddlebred horse.

Abstract: Due to the incorporation of the Golden American Saddlebred Horse Association (GASHA) into the American Saddlebred Horse and Breeders Association (ASHBA), breeding for coat color has become more challenging for horse breeders. However, with this merger, pedigree tracing can be of value in pinpointing foundation bloodlines within the GASHA that influence production of the golden coat phenotype. Objective: The study objective was to document the historical origins of the GASHA through pedigree tracing to determine the influence of dilution alleles that produce the golden coat phenotype. Methods: A sample of 550 horses was obtained from the GASHA Official Directory. Using the All-Breed Database, sampled horses were examined for pedigrees suitable for color inheritance analysis with 507 being found to have extended pedigrees with coat color documentation that were traced to record lineage and associated coat color assignments. Results: Pedigrees traced determined 43 % carried the champagne dilution allele, 36.1 % carried the crème dilution allele, and 20 % had non-informative pedigrees that either traced back to unknown ancestors or were found to have incorrect ancestry. Another 0.9 % were determined to be obligate carriers for the crème dilution allele due to conflicting color designation. All pedigrees traced back to six foundation mares with the majority tracing back to two of these mares, Maud which carried the champagne dilution allele and Allens Queen which carried the crème dilution allele. Conclusions: Through pedigree tracing the GASHA origins were documented, unveiling genetic contributions for today's GASHA golden coat phenotype that can facilitate selective breeding practices.