🎨 Modifiers
Color Modifiers
Modifiers alter the appearance of the base coat but do not dilute it.
Flaxen (F)
Flaxen is a recessive modifier that lightens the mane and tail of chestnut horses. Depending on expression, flaxen can range from a slightly lighter mane and tail to a nearly white mane and tail.
Inheritance
| Genotype | Result |
|---|---|
| F/F | Flaxen |
| F/f | Carrier |
| f/f | Non-Flaxen |
Because flaxen is recessive, a horse must inherit a flaxen allele from both parents in order to visually express it.
Expression
Flaxen only affects chestnut horses. Bay and black horses may carry flaxen but will not visually express it.
              Flaxen Chestnut                        Flaxen Liver Chestnut                  Flaxen Red Chestnut
Silver (Z)
Silver is a dominant modifier that affects black pigment. It lightens the mane and tail while having no effect on red pigment.
Inheritance
| Genotype | Result |
|---|---|
| Z/Z | Silver |
| Z/z | Silver |
| z/z | Non-Silver |
Only one copy of silver is required for expression.
Expression
Chestnut horses may carry silver but will not visually express it because they do not produce black pigment.
                         Silver Bay                                           Silver Black
Sooty (Sty)
Sooty is a dominant modifier that adds dark hairs throughout the coat. Expression can range from subtle dark shading to heavy darkening across the entire body.
Inheritance
| Genotype | Result |
|---|---|
| Sty/Sty | Sooty |
| Sty/sty | Sooty |
| sty/sty | Non-Sooty |
Only one copy is required for expression.
Expression
Sooty affects bay and chestnut based horses
                     Sooty Bay                          Sooty Dark Bay                         Sooty Seal Bay
                    Sooty Buckskin                      Liver Chestnut                       Chocolate Palomino
Gray (G)
Gray is a dominant modifier that causes progressive depigmentation over time.
A gray horse is born its original colour and gradually lightens as it ages.
Inheritance
| Genotype | Result |
|---|---|
| G/G | Gray |
| G/g | Gray |
| g/g | Non-Gray |
Only one copy is required for expression.
Expression
Gray can occur on any base colour.
Examples:
- Black → Gray
- Bay → Rose Gray
- Chestnut → Rose Gray
The horse's original color remains genetically present underneath the graying process.
               Black Base - Stage 0                          Stage 1                                Stage 2Â
                    Stage 3                             Stage 4                             Stage 5
                                  Final Form A                                 Final Form B
               Bay Base - Stage 0        OR          Chestnut Bay - Stage 0                      Stage 1Â
                     Stage 2                               Stage 3                                 Stage 4Â
                                  Final Form A                                 Final Form B