How Horse Colors Happen

How Horse Colors Happen

How do horses get their color? These three simple steps will help you identify any horse color.

Two bay horses and a gray horse stand looking to the right of the image. The horses are standing in a rope corral with a cowboy behind them. The image is tightly cropped so only the horse's heads and necks are showing. 

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By Andrea Caudill

The entire rainbow of horse colors that decorate the American Quarter Horse are built on a few simple basics. Working through this easy process will help you identify a horse color.

Step 1: Pigment

The basics begin with the pigment that create the color in horse hair. There are two pigments, one causes black and the other causes red.

Which of these colors is expressed is controlled by the extension gene. A horse has two copies, which are written in capital or lowercase letters, depending on if the gene is dominant or recessive. (Example: EE, ee or Ee)

  • Black is a dominant color.
  • Red is recessive.

This means a black horse can have two copies of the black gene (homozygous, EE) or one copy (heterozygous, Ee) and will still appear black. A red horse will only appear red if it has no copy of the black gene (ee).

That is why, for example, you could cross a black horse (EE or Ee) with a red horse (ee) and get a red horse (ee) – the black horse was heterozygous (Ee) for black.

All the other colors of horses are just variations of these two base colors, caused by what is termed color modifiers.

Black-based colors include:

  • Black
  • Bay
  • Brown
  • Brown roan
  • Buckskin
  • Perlino
  • Smoky black
  • Grullo
  • Dun
  • Blue roan
  • Bay roan
  • Classic champagne
  • Amber champagne

Red-based colors include:

  • Sorrel
  • Chestnut
  • Palomino
  • Cremello
  • Red roan
  • Gold champagne
  • Red dun

Sorrel and chestnut – the most common colors in the American Quarter Horse – are genetically the same color.

Step 2: Agouti Gene

The second step in identifying a horse’s color is identifying whether or not the horse carries the agouti gene.

This is the most common color modifier, and is responsible for causing the color pattern bay, dun and buckskin horses. The agouti gene restricts the black pigment in a horse’s body to only its points (mane, tail, legs, ear tips).

A red horse can carry the agouti gene, but won’t express it, since it genetically lacks the black pigment.

Colors that visually demonstrate the agouti gene include:

  • Bay
  • Brown
  • Buckskin
  • Perlino
  • Dun
  • Bay roan
  • Brown roan
  • Amber champagne

Step 3: Color Modifiers

Once you’ve identified a horse’s base color (black or red) and whether or not it carries the agouti gene, the next step is to identify another color modifier that is in action to create the horse’s color. 

Color modifiers include:

  • Gray – A dominant gene that will ultimately turn any base horse color gray.
  • Cream – Modifies the color of red pigment by lightening it, but leaves black pigment alone. Colors include palomino, buckskin, smoky black, cremello, perlino, smoky cream.
  • Dun – Modifies the color of red pigment, but leaves black pigment alone, and adds primitive markings. Colors include dun, grullo or red dun.
  • Roan – Adds white hair over the top of a base color. Colors include blue roan, bay roan, brown roan and red roan.
  • Champagne – Modifier that dilutes both black and red pigment. Colors include classic champagne, amber champagne and gold champagne.
  • Pearl – Rare modifier that resembles champagne. This is not an official AQHA color, and a horse with this dilution will be registered as its base color and have the gene’s presence noted.
  • Silver dapple – Rare modifier that dilutes the color of black pigment. This is not an official AQHA color, and a horse with this dilution will be registered as its base color and have the gene’s presence noted.
  • White - Horses born with the dominant white gene are born with pink skin and white hair, but have dark eyes. It is also possible for the sabino gene (which can cause excessive white markings), in its most extreme form, to turn the horse almost totally white. 

If you have coat-color questions, contact the AQHA Member Experience Team at 806-376-4811.

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