What are Dilutes and Double-Dilutes?

Reality Recolored

You may have noticed the sudden disappearance of some sub-categories under the Realistic Colors heading in the drop-down.

I just didn’t have enough of the individual colors to warrant splitting them out, so I have combined all of the dilute and double-dilute colors into a Dilutes category. They will still be tagged with the appropriate body color, so you can still sort out by dun or cremello if you want.

But what on earth is a dilute? Glad you asked!

In the genetics of horse coats, you have three basic colors: Black, Bay, Chestnut.

These three colors are then ‘diluted’ by Cream, Champagne, Dun, Pearl (Barlink Factor), Silver, Roan, and Grey.

Black, Bay, Chestnut

These three colors are base for all other horse colors. The three combinations come from two genetic markers: Extension (red factor) and Agouti (black factor).

Dark bay horses are not the same as black horses, but I’ve combined the two in the gallery since I paint a LOT of dark bay and not as much solid black.

Extension (red factor)

ee – all red, no black (chestnut)
Ee – red and black (bay)
EE – all black, no red (black)

Agouti (black factor)

aa – black body and points (black)
Aa – black points (bay)
AA – black points (bay)

Black
Bay
Chestnut

Diluting Genes

Working out from the base colors, there are a wide variety of diluting genes. Most of these genes are all or nothing, but some express as single/double, meaning that a horse with two ‘on’ switches will be more diluted than a horse with one.

The various dilutions can also be combined, leading to even stranger colorations. For obvious reasons these rare colorations are much more prevalent in the model horse world than in real-life. (Depending on the current show ring trends, they may even dominate the tables!)

As you can see, I’m missing a lot of these colors from my own galleries, so please check out the Reference Links at the bottom of the post for real-life examples!

Cream

Cream lightens both red and black coat colors and is a double-dilution gene. A single cream will get you palominos, buckskins and smoky blacks. A double will get you cremellos, perlinos and smoky creams. The single dilution effect on the red color is much more dramatic than the black (as you can see in buckskins and smoky blacks), but a double-dilution turns all of them more-or-less white.

Palomino
Buckskin
Cremello

Champagne

This is a all or nothing gene that affects both red and black pigments and produces gold champagne (chestnut), amber champagne (bay), and classic champagne (black). These colors can be very similar to other dilutes, but can be told apart by the hazel eyes and pinkish, freckled skin.

Amber Champagne

Dun

This is a all or nothing gene and produces black dun (blue/gullo/grulla), red dun, bay dun (yellow/classic). Dun horses have a dorsal stripe, leg barring, and sometimes shoulder stripe as well.

Bay Dun
Bay Dun

Pearl (also known as Barlink Factor)

This is a all or nothing gene and produces a uniform apricot color of body hair, mane and tail. Interestingly, this can combine with the Cream gene to produce a pseudo-Cream double-dilute only with pale skin and blue or green eyes.

Silver

This is a all or nothing gene and produces a dilution of black pigment but has no effect on red pigment. Thus it only affects bay and black horses, turning black horses chocolate with flaxen mane and tail and bay horses into pseudo-chestnuts.

Roan

This is a all or nothing gene and causes white hairs on the body, but not the legs, head, mane or tail. None of the roans I have currently painted are actually true roans, they are all sabino roans (having white markings extending into the head, legs, mane and tail).

Grey

This is a all or nothing gene and causes a horse to go gray as it ages. The speed of the graying process can vary, but moves in predicable patterns.

Bay Going Grey
Steel Grey

Reference Links

These are the pages that I used to source the above information (although the photos are obviously all mine). Follow these links for real-life examples of the various coat colors, as well as some interesting variations.

  • The Regents of the University of California, Veterinary Genetics Laboratory: Equine Coat Color Tests web page accessed April 15, 2011.
  • Model Horse Reference: Horse Coat Color Genetics web page accessed April 15, 2011.
  • Equine Color: Equine Color Genetics web page accessed April 15, 2011.
  • Horse-Genetics.com: Roan Horses web page accessed April 15, 2011.
  • ‘Homecoming’ Blog: The Grey Gene in Horses web page accessed April 15, 2011.