Somatic Markings are patches of a horse's coat where one trait appears to be "switched on" or "switched off" compared to the rest of the coat.
(Above example is a Chestnut with Bay somatic caused by the Ee gene "switching on")

Somatic expresses in irregular blotches, strips, or splatters of marks and should not resemble any other marking in shape.
Symmetrical, uniform, or intentional-looking markings (such as stripes, skulls, patterns, symbols, etc) cannot be made with Somatic.
Somatic should have crisp, clear outlines; edges should not be blurry or gradients.

Somatic markings may not overlap or interact with Chimera - no more than 3 base colors may appear on any horse.

Only one of a horse's Traits (base color, modifier, or marking) may be affected by Somatic markings.
Somatic markings are not inherited, and do not affect a horse's genotype.
Any horse can be designed with a somatic marking at any time, including Free Imports.

• Coat: Will show the color change caused by the changed trait.
• Mane and Tail: May be affected by the somatic color.
• Skin: May be affected by the somatic color.
• Eyes: No effect.
• Hooves: No effect.

Maximum Range:

• Maximum: Up to 1/4 of the horse's visible area covered by Somatic markings.

Somatic Colors:

• On Foals: May "switch on" or "switch off" any one trait that is genetically possible from the parents, or express any base color gene (E/A) possible from the parents.
• On Imports: May "switch off" any one trait on the import genotype or show different base color genes (E/A). May not show any traits that the import does not have.
• Anomalies are not associated with genes, and so cannot be affected by somatic markings.