In Horses, Black Coat Color Is Influenced by the Dominant

Short Answer

In horses, black coat color is influenced by the dominant allele (B), and chestnut coat color by the recessive allele (b). Trotting gait is due to a dominant gene (T), pacing gait to the recessive allele (t). Give the genotype and phenotype of the horse you would use in a testcross to determine the genotype of a black trotter.