Introduction to Horse Genetics
Part One
My goal is to explain genetics step by step to help the average horse owner/rider understand the complicated scheme of genetics. How often do you pick up a magazine and read “homozygous tobiano, negative for OLWS, heterozygous black, will always produce color.” This is not just linked to Paint horses and pinto breeds, but rather color is becoming important in the horse world. As the saying goes, no horse is of a bad color, but a good color doesn't hurt either. As more horses are available for purchase, people are willing to spend that extra money on a desirable, flashy color that will stick out in the show ring, on the trail, or just glitter and gleam in the pasture.
So where should we start?
Let's begin with basic horse colors. After all, to understand horse color genetics, one first needs to understand colors. Only a few colors will be shown here, as there are a plethora of horse colors that would take days to go through.
The horse above is a chestnut. For our purposes genetically chestnut and sorrel are considered the same color.
This
horse is considered a black. Black and chestnut are considered the
two basic colors of the horse world. Blacks are true jet black with
no brown spots on the nose, flanks, or underbelly.
This
horse is your typical bay. Bays have a brown/reddish body with black
“points”. These points are the extremities of the body
and include the lower legs, tail, mane, muzzle, and often the tips of
the ears.
This
is a grey (gray) horse. They are born any other color and grey out
throughout their life as they age. Greys can be “white”,
dappled grey like pictured, rose grey, steel grey, fleabitten grey,
etc.
This is just four colors in a wide arrange of the horse coat color pallet, however it is essential that you're able to picture the horses as we progress throughout our explanation.
The next important concept to understand is that of homozygous and heterozygous. A horse has two copies of every gene. If they have two copies of the same, exact gene they are considered homozygous. If they have two different forms of the gene, they are heterozygous.
This is part one, I will start on part two shortly.