Great variation is present in horses of today. There are large horses and small horses, riding horses and driving horses, draft horses and race horses. There is, no doubt, a type of horse for almost every possible purpose.

Inside the cells of all animals are found chromosomes and genes. Chromosomes are paired thread-like structures which carry the genes. Each body cell contains a certain number of pairs of chromosomes (e.g. horse - 32, man - 23). Genes are the units of inheritance which dictate what an individual will look like. This outward expression, called phenotype, is a result of an animal's genetic makeup, called genotype. As chromosomes occur in pairs, so do genes. Two genes exist side by side, each on one of the chromosomes of a pair. An allele is one member of this pair of genes, or a partner gene. The specific position, where paired genes are found, is called their loci.

Because so much more is known about genetics and animal breeding today than was known at anytime in the past, there is greater opportunity today to breed superior animals than at anytime in the past. Greater than average success in horse breeding can be had by intelligent application of modern animal breeding principles coupled with good husbandry practices.

A breeder who understands basic genetic principles may have an edge in choosing the most appropriate stallion from those available to mate to his mare. At least the breeder who has a knowledge of basic genetic principles can better understand the causes for which a horse produced from a given mating turns out the way it does.

For more information see the publication: The Genetics of Equine Coat Color by Doug Householder