Modifiers

Grey (or gray) is a horse color caused by one or two copies of grey on any coat color. It causes progressive lightening (“greying”) of the coat.

Flaxen is a coat color modifier that lightens the mane and tail of chestnut horses.

Sooty or smutty is a coat color modifier that darkens the coat of chestnut and bay-based horses. Foals are born with a “normal” coat color, and graudally darken as they age.

Pangaré, also called or mealy, is a coat color modifier that lightens the soft body parts of chestnut and bay-based horses.

The STX17 gene is responsible for the color grey in horses.