Explanation of the genes required for each of these coat colors and what crosses will produce.
Color coat genetics can be very confusing, but many breeders want to figure out what their foals might be for various reasons. Others don’t care and can’t wait to see what comes out! For those of you who are trying to figure out what you get if you breed your mare to a certain stallion, here are a few rules:
A chestnut carries two red genes and allows for the color red only. The chestnut has no other color genes and no black genes. If you breed a chestnut to a chestnut, you will either get sorrel or chestnut. So, a sorrel or chestnut that is bred to a sorrel or chestnut will produce a sorrel or chestnut every time. Hint: A lot of chestnuts are mistaken for sorrels. A chestnut can have a flaxen mane and tail and is not a palomino, although some people call them chocolate palominos.
A sorrel has the same genetics as the chestnut. They have two red genes and no black genes. If you breed a sorrel to another color, the sorrel will come from the sorrel parent only. If you breed a sorrel to a sorrel or chestnut, you will get a sorrel or chestnut 100% of the time. This is the most common color of the Quarter Horse.
A gray will have the same color genetics of any other horse including roans. The gray horse’s color genetics depend on what color the horse was before the horse shed and turned gray. A gray foal will have at least one gray gene from a gray parent. You cannot get a gray from two parents that are not gray; regardless of whether or not gray is in the pedigree. Gray genes do not skip a generation either.
The color of a bay can range from a sorrel color to a dark brown, almost black, color. A bay has black color because of a gene called the agouti gene. This gene causes black to only be located at certain points on the horse. The base color of the horse is a variation of the red gene. A bay must have one black parent or a parent with black points. They will always carry a black gene. Some horses are homozygous for the agouti gene, which means that they have two copies of the agouti gene (one from each parent.) Some are homozygous, which means that they only have one agouti gene. A homozygous bay will always produce a foal with black points.