What is the Homozygous Black Gene?
A foal inherits 2 genes for base coat color, 1 from each parent. A base coat is either red or black. Bay, Palomino, Tobiano, Grey horses are all the result of a modifier gene acting upon the base coat color. The red coat color in horses is inherited as a trait recessive to black. A blood test for the red factor, based on DNA analysis, provides the information to determine what color offspring a horse can throw. The absence of the red factor presents itself as “E”. “E” = no red factor detected. The horse can be assumed to be homozygous for black pigment (EE). It cannot have red foals (chestnut or sorrel) regardless of the color of the mate. The basic color of the horse will be black or bay, but depending on genes at the other color loci, the horse may be buckskin, zebra dun, grulla, perlino, gray, white or any of these colors with the white hair patterns tobiano, overo, paint, roan or appaloosa. A Bay horse is a horse with a base coat of Black with a modifier gene called the Agouti gene
