Dun is a thin striping gene that is mostly situated along the spine, though there can also be stripes on the ankles/wrist of a colonist as well as near the tailtip. Stripes should be perpendicular to the spine, though some minor curving is allowed. The majority of the striping is on the shoulders, also known as withers, of a colonist. There can also be some striping on the legs and tail, but this should wrap around the limbs instead of being perpendicular to the ground.
This gene requires a dorsal stripe, or dark line along the spine, for at least half of the spine.
Dun should be darker than any markings that are layered below it. It should also be distinguished as darker than the mane, though can instead be the same colour as the mane if the mane is already exceptionally dark, so long as the marking is still visible. Black (______KK or CCMMYY__) colonists may have dun that is difficult to distinguish from the base coat due to their darkness. In those cases, it may be recommended to lighten the base coat on the swatch a bit.