The
silver or
silver dapple (Z) gene is a
dilution gene that affects the
black base
coat color. It will typically dilute a black mane and tail to
flaxen, and a black body to a shade of brown or chocolate. It is responsible for a group of
coat colors in horses called "silver dapple" in the west, or "taffy" in Australia. The most common colors in this category are
black silver and
bay silver, referring to the respective underlying coat color.