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Known or under-investigation dilutions:
Cream Dun Champagne Pearl Silver Flaxen Light Black Mushroom Dilution Chart


  • Dilution means less concentration; like milk dilutes the color of coffee, a dilution gene causes a lighter hair color.

  • Dilution genes contain instructions to the cells producing pigment (color) in the horse's hair and skin to "spread the pigment thinner", or to "dilute" the pigment.

  • Dilution genes do not "switch off" pigment (color), as white-spotting, gray, and Appaloosa genes do in horses,
    or as albino genes do in mice.

This picture, taken by the webmaster in 2006, is of a black-based (brown) champagne-dilution (sable) foal near Bend, Oregon.  Because the black color is diluted, the coat, mane & tail are not black, but a very interesting, lighter color.  The eyes are blue, and the skin is pink, all over.  As the foal ages, its eyes will turn tan, and its skin will develop abundant dark freckles.  The skin does have some pigment in it, and is a different shade of pink then the pigment-free skin under pure-white markings.
  • NEW TERMS!  Some dilution genes are dominant, but some are incompletely dominant, and some are incompletely recessive.

    • Incomplete dominant genes : expressed partially when one is present, more when double (HOMOzygous)

    • Incomplete recessive genes : expressed minimally when one is present, completely when double (HOMOzygous)

To differentiate them from incomplete dominant or incomplete recessive genes, sometimes "regular" dominant or recessive genes are called "simple dominant" and "simple recessive" genes.

This picture, also taken by the webmaster in 2006, is of a "teen-aged" Iberian filly of the pearl-cream dilution in Acton, California.  She was born with pink skin and blue eyes, and her skin was already developing freckles typical of the pearl dilution -- usually somewhat muted compared to champagne freckling.  Her eyes eventually turned more of a greenish color.

The currently known dilution genes are:

Cream

Dun

Champagne

Silver

Pearl

Flaxen


  • Cream

    • The cream gene is abbreviated "Cr" in genetic symbols.  The gene for absence of cream is abbreviated "cr".

    • The cream gene is an INCOMPLETE DOMINANT gene.  This means that if one gene is present, it will be expressed moderately, and if two copies are present, it will be expressed in a more extreme manner.

    • One cream gene will lighten the base colors to the single-cream colors, such as palomino or buckskin (illustrated) or smoky brown or smoky black.

    • Two cream genes will lighten the base colors to the double-cream colors, such as cremello or perlino (illustrated) or brown cream or smoky cream.

  • Dun

    • The Dun gene is abbreviated "D" (or "Dn") in genetic symbols.  The gene for absence of Dun is abbreviated "d" (or dn).

    • The Dun gene is believed to be a (SIMPLE) DOMINANT gene.  This means that if one gene is present it will manifest fully, and if two are present it manifests no differently than with one.

    • The Dun gene lightens the body color and leaves stripes of the original color along the back and on the upper legs, most of the mane & tail, and other specific places.

      • this means that dun on chestnut will result in a washed-out-red body color with chestnut colored stripes; on bay will result in a tan body color with dark red points and stripes (sometimes striping on a bay dun can look black; presumably that horse would have been a sooty bay without the dun gene); on black will result in a dove gray to purplish to olive brown body color with black points and striping; on brown, dun looks much like it does on black, and a DNA test is usually needed to prove the difference.

    • FOR MORE ON DUN, see this web site's dun section; also DunGenes.org, also by this webmaster.

  • Silver

    • The Silver gene is abbreviated "Z" in genetic symbols.  The gene for absence of Silver is abbreviated "z".

    • The Silver gene is a SIMPLE DOMINANT gene.  This means that if one gene is present it will manifest fully, and if two are present it manifests no differently than with one.

    • The Silver gene ONLY AFFECTS BLACK PIGMENT.

    • Silver "super-dilutes" the mane & tail of a horse with black pigment to a flaxen or silvery color.

    • Silver dilutes the black pigment on the body to a chocolate-brown shade (illustrated).

    • Silver does not dilute the red pigment of a bay based horse, leaving a red body with flaxen mane & tail and chocolate-brown lower legs (where the black is diluted). (not illustrated)

  • Champagne

    • The Champagne gene is abbreviated "Ch" in genetic symbols.  The gene for absence of Champagne is abbreviated "ch".

    • The Champagne gene is a SIMPLE DOMINANT gene.  This means that if one gene is present it will manifest fully, and if two are present it manifests no differently than with one.

    • The Champagne gene lightens the hair, skin and eye color (illustrated on bay).

    • Champagne foals are born with pink skin and blue eyes; the pink skin color usually deepens and always develops dark freckles, and the eye color turns to amber or light brown.

    • For more about Champagne, see the International Champagne Horse Registry's web site, also by this webmaster.

  • Pearl

    • The pearl gene is abbreviated prl.

    • Pearl behaves as though it is an allele (mutation) of cream.

    • It is an incomplete recessive gene; one pearl gene is minimally expressed, if at all, when no cream is present.

    • It reacts with cream to form a type of double-dilute: a cream pearl, with pink skin and muted freckles.

    • A horse with two pearl genes will be a diluted color, with pink skin and muted freckles  (illustrated on black).

    • For more about Pearl, see the Pearl section of the New Dilutions web site, also by this webmaster.

  • Flaxen

    • It was once believed by some that flaxen was a simple recessive gene.  However, we now have evidence that two flaxen chestnuts do not always produce a flaxen foal. So...

    • At the time of this writing, the mechanism by which flaxen is inherited is unknown.

    • Flaxen only affects red pigment in manes and tails of red-based horses.


Besides these six currently-known dilution genes, one of which (flaxen) is far from understood, there are at least two other possible dilutions under investigation:  light black and mushroom.  These are extremely rare, the former occurring mostly in one family of Arabian horses, and the latter almost exclusively in one "family" of English Shetland ponies.  To follow or join in these investigations, click either of these links:

Light Black                Mushroom

To follow the educational, logical progression of this web site, click "Next", below.

Cream Dun Champagne Pearl Silver Flaxen Light Black Mushroom Dilution Chart


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