The color of a horse is based on two base colors: red (chestnut in color) and black. It is off these two colors that all the other coat colors are formed. Black is formed by the E locus, and is dominant over red. EE and Ee are black, ee horses are red (chestnut). Black foals are usually a mouse-brown color, that sheds out to black.
The genes affecting color
- The Agouti Gene (A): bay coloration, which is always on a black base.
- The creme gene (Cr): Produces palomino, cremello, buckskin, and perlino. Also smoky black and smoky cream.
- The creme gene on red base: palomino and cremello
- The creme gene on black base: smoky black and smoky cream
- The creme gene on bay (black base with the agouti gene): buckskin and perlino
- Is an incomplete dominant gene
- The champagne gene (Ch): amber, gold, classic, and ivory.
- The champagne gene on red base: gold
- The champagne gene on black base: classic
- The champagne gene on bay (black base with agouti): amber
- The champagne gene on cream (the creme gene): ivory
- Is a dominant gene
- The silver dapple gene (Z): black silver, red silver, bay silver
- The Silver gene on black base: black silver
- The Silver gene on red base: red silver
- The Silver gene on bay (black base with agouti gene) : bay silver
- The dun gene (D): grulla, red dun, bay dun
- The dun gene on red base: red dun
- The dun gene on black base: grulla
- The dun gene on bay (black base with agouti gene): bay dun
- Is a incomplete dominant gene
- The white gene (W): white
- One copy of the gene produces a pure white horse
- Two copies of the gene are lethal
- See Gray (horse) for more information on white horses
- The roan gene (R): strawberry roan, red roan, blue roan
- Roan on red: strawberry roan
- Roan on black: blue roan
- Roan on bay (black base with agouti): red roan
- One gene copy will produce roaning
- Two copies are lethal
- The Rabicano gene (Rb)
- Causes white hairs on flanks and top of tail, sometimes on ribs as well
- Gray gene (G): gray (including dapple, rose, fleabitten)
- See Gray (horse) for more information
- Any color (any base, or base + combination of above genes) + Gray= gray
- The gray gene creates a process in which the horse changes gray. It is not born that color.
- The Tobiano gene (T):
- causes a white pattern where white crosses over the spine
- The Overo gene (O):
- Is dominant
- Is lethal in its homozygous dominant form (lethal white syndrome)
- White markings appear at belly and spring upward
- The Sabino gene (Sb):
- Homozygous Sabinos are usually almost completely white
- The splashed white gene (Spl):
- Differs from overo in that the legs are white
- Has white face with blue eyes
- Appaloosa:
- The genetics for this coat coloring is still not completely understood
- Flaxen:
- The genetics for flaxen is not yet understood
- The flaxen gene lightens the mane and tail of horses
The colors diluted
Creme gene (C):
- Dilutes the red base coloring to gold when one copy is present
- Dilutes red base to cream when two copies are present
- Can dilute black base with two copies
Champagne gene (Ch):
- Dilutes red base to gold color
- Dilutes black base to liver/chocolate color
- One or two copies present has no affect on final color of the horse
Silver dapple gene (Z):
- Dilutes black base: mane and tail to flaxen, coat to chocolate
Dun gene (D):
- One or two copies has no affect on the final color of the horse
- Seems more concentrated in diluting the body than the mane, tail, or head
- Similar to the creme gene, but also produces primitive markings: red to gold
The genes in coloring
Chestnut/Sorrel: ee, also Aaee or AAee (A is not shown because the horse has no E (black) coat)
Black: E (EE or Ee)
Bay: A-E (AaEe, AAEe or AAEE )
Zebra Dun: A-E-D (E= black color, A restricts it to the points, D=dilutes the colors and adds dun factors)
Red Dun: aa-D-ee (ee= red coat, D= dilutes color, adds dun factors)
Grullo/Grulla: aa-D-E (E=black coat, aa is recessive so does not restrict it to points, D=adds dun gene)
Palomino: Crcr-ee (ee=red coat, Crcr=dilutes red color once)
Buckskin: Crcr-E-A (E=black coat, A=restricts black to points, Crcr=dilutes the red on the horse)
Cremello: crcr-ee (ee=red coat, crcr= dilutes red color twice)
Perlino: crcr-E-A (E=black coat, A=restricts black to points, crcr=dilutes the red on horse twice)
Smoky Black: Crcr-E-aa (E=black coat, aa=recessive so doesn't restrict it to points, Crcr= dilutes the red once, but no red on black horse)
Black Cream: crcr-E-aa (E=black coat, aa=recessive so doesn't restrict it to points, crcr=dilutes the red twice, but no red on black horse)
Red Silver: Z-ee (ee=red coat, Z=dilutes black on horse, but there is no black on a red horse)
Black Silver: Z-E-aa (E=black coat, aa= recessive, so does not restrict to points, Z=dilutes black on horse)
Bay Silver: Z-E-A (E=black coat, A=restricts black to points, Z=dilutes the black on horse--the points)
Gray: G or Gg (G= any coat base or any modified base is turned gray)
Strawberry Roan: R-ee (ee=red coat, R= roan affect)
Blue Roan: R-E-aa (E=black coat, aa= recessive, so does not restrict black to points, R= roan affect)
Red Roan: R-E-A (E=black coat, A= restricts black to points, R= roan affect)
Rabicano: Rb (Causes rabicano on any base coat or modified base coat)
Tobiano: T (TT or Tt- causes Tobiano pattern on any base or modified base)
Overo: O (OO or Oo- causes overo pattern on any base or modified base)
Sabino: Sb (SbSb or Sb- homozygous SbSb is usually completely white)
White: Ww (Ww on any base or modified base will produce white, WW is lethal)
Classic Champagne: Ch-E-aa (E=black coat, aa=recessive so doesn't restrict to black points, Ch=champagne dilution)
Gold Champagne: Ch-ee (ee= red coat, Ch= champagne dilution)
Amber Champagne: Ch-E-A (E= black coat, A= restricts black to points, Ch= champagne dilution)
See also
