Yes, scientifically color has nothing to do with the heart of a race horse or whether a horse can "cow", jump fences, run barrels or do any other specific job. A correlation has never been found between color and performance ability.

Yet, color can be a big drawing card when a horse is for sale. It can definitely make a difference in the amount of attention a horse gets in the show ring.

Most horsemen seem to have a color preference. Some prefer palominos, others like grays, or buckskins, or tobianos. . . For every color there is a group of people who feel that their color is the most beautiful expression of the body of the horse.

Perhaps it is because of our human preferences that coat color genetics is one of the few areas of equine genetics that scientists have been able to develop sophisticated theories on how specific genes determine the color of a horse's hair.

The action of the remaining color genes is purely hypothetical. Because of this, theories may change as more and more tests become available to identify specific genes.

Identifying coat colors can also be cause for confusion. There is a tremendous range of shades within a color and different types of colors without any recognized names. There are also coat colors that appear to be identical, but are under the influence of different genes.

Breed associations have also contributed to some of the confusion.

Take, for example, the gray gene. Technically, whenever the gray gene is present in the dominant form, the horse is a gray regardless of its base coat color. Any color horse (with the exception of the true white) can turn gray.

However, The Jockey Club registers their horses under a different system. If a red horse has white hairs in its coat, The Jockey Club refers to it as a roan –regardless of gene creating the coat. According to The Jockey Club, grays are dark horses which are graying.

The Jockey Club is not alone. Most breed associations do not register coat colors according to the current theory of coat color genetics.

And to make it even more confusing, these organizations do change their color categories on their registration forms.

For example, The American Quarter Horse Association changed the description of a "buckskin". In the past a buckskin was any canvas colored horse with black points. It could have zebra markings and a line-back and still have been a buckskin.

Today, all line-backed horses with zebra markings are referred to as duns - that is, unless they are sorrel or chestnut duns. These are called red duns while black duns are called grullas.

The roan horse recognized by the APHA and the AQHA can be another source of confusion.

The AQHA has two choices for roans - the blue roan and the red roan - the category which lumps together bay roans and sorrel/chestnut roans.  That is, until 2002 when the registration form added a separate category for bay roans. 

Up until recently, roan Paint Horses were registered according to the same guidelines used by the American Quarter Horse Association. However in 2000, the APHA decided to divide the roans into the three basic colors:

Confused?

In spite of having to muddle through the confusing labels used by the various breed organizations, it is possible to stack the deck in order to increase the probability of producing a specific colored offspring - if you understand the underlying genes which create the colors.

But, first, before delving into the the genes that control coat color genetics, there are three concepts that you need to understand:

Genes and how they are passed to the next generation

How a matched pair of genes basically relate to each other

How to predict the possible gene combinations

Lets get started.

Genes are the basic units of inheritance.

Genes are linked together to form a chromosome similar to the way pearls are threaded together to make a strand.

Chromosomes exist in pairs. Each gene on the chromosome has a mate or "allele" in exactly the same place or "loci" on the chromosome's matched pair.

Each particular species has a specific number of chromosomes. For example a horse has 32 pairs of chromosomes. A donkey has 31 chromosomes pairs.

Basically each pair of genes codes for a specific job. A pair of genes can control something as obvious as whether or not a cow will have horns or be as subtle as coding for a specific portion of a biological molecule.

During the cell division when one cell divides into either two eggs or two sperm cells, only one member of each chromosome pair goes into each new cell. This provides every sperm and egg with only one copy of each gene.

For example suppose a stallion has at one gene location along the chromosome, genes designated as E and e. When that cell divides into two sperm cells, one resulting sperm cell will get the chromosome with the e and the other resulting sperm cell will get the other chromosome with the "E".

This same process takes place in the mare as she produced eggs.

Upon fertilization the single chromosomes find their corresponding mate and pair back up. The resulting individual again has two genes at each location – one from its dam and one from its sire.

To help keep track of the genes whose function is thought to have been identified, geneticists assigned a letter or two of the alphabet to each pair.  For some of the newly identified genes there may still more than one common abbreviation.   For example, the cremello gene which creates palominos and buckskins may be referred to as CR or C  with a cr superscript.

In this course, we are going to use the simplest codes but don't get tunnel vision about the gene abbreviations.  It is inevitable that some of the notations will change as geneticists learn more about the genes that control coat color.

Here is a list of genes that we will be discussing and the gene abbreviations that we will use.

(When you are ready to take the Sample Quiz CLICK HERE.)