|Yellowish horse, black points. Is it a buckskin or a dun? Well, it depends on which
registry you consult, although there is some agreement in their definitions.
yellowish body color (although the shade of yellow can vary tremendously). The
International Buckskin Horse Association (IBHA) says that "buckskin" should be
the color of "tanned deerhide" with dark points (mane, tail, and legs). Dun is a
similar color although, according to the IBHA, it is a "duller shade than
buckskin." In the past, the dun color was often considered to be more sooty or
smutty. A horse with a mane and tail that wasn't black was also called dun.
Recently scientists have determined that there are separate genes that are responsible
for the buckskin and dun colors. Buckskin is one result of the "c cr" dilution
gene, while dun is one result of the "dun" dilution. Either dilution gene will
lighten the body color of a horse, much like adding a little white to a darker color of
paint. Therefore the bay color would become buckskin or dun color. And just as there are
many shades of bay, from a pale sandy bay to a dark blood bay, there are many shades of
buckskin and dun, from a pale buttermilk to an almost chocolate color.
Bay is not the only color affected by the dilution genes. A sorrel or chestnut base
color would become red dun (pinkish or flesh-colored with red or chestnut points) when
combined with the "dun" gene or palomino (golden body with a lighter or white
mane and tail) when combined with the "c cr" gene. A black or dark brown base
color would become grullo (pronounced grew-yah) with the "dun" gene and a dark
to almost black buckskin when combined with the "c cr" gene. Grullos are not
very common, but can be a mouse gray to a camouflage-olive, often with a metallic-like
sheen. This color should not be confused with gray or blue roan. Each hair on a grullo is
the diluted color, not a mixture of white and dark hairs.
The only way for a horse to have one of these colors is if he carries a dilution gene
which he must have received from one of his parents. If one parent has one copy of a
dilution gene and one parent does not have it, then the resulting foal has 50% chance of
also carrying one copy of the gene. If both parents have one copy of a dilution gene then
the resulting foal has a 25% chance of not carrying the dilution gene, a 50% chance of
carrying one copy of the dilution gene, and a 25% chance of carrying two copies of the
dilution gene. A horse that carries two copies of the gene would be homozygous for that
gene. All of his foals would carry at least one copy of the gene and thus show the diluted
A horse that is homozygous for the "dun" dilution gene looks the same as a
horse that only carries only one copy of the gene. However a horse that is homozygous for
the "c cr" will be an even more dilute color called perlino or cremello. Both
colors are almost white and usually have blue eyes. The cremello has cream-colored points
while the perlino has points with more of a bluish tinge. This slight amount of color is
often unnoticeable except where it meets a white facial or leg marking.
carrying this "double dilution" would only have foals with the buckskin or
palomino color. The AQHA has only recently recognized the perlino and
So now we know that a palomino, perlino, or cremello has the "c cr" dilution
gene, while the grullo has the "dun" dilution gene, but how do we tell the
buckskin from the dun? The "dun" gene is associated with primitive markings,
also called dun factors. The most common is a line down the back, from the base of the
mane to the top of the tail. This line is called a dorsal stripe, spinal stripe, or
line-back. Primitive markings also include striping on the legs, generally across the
knees and hocks. These markings are called leg barring or tiger- or zebra-stripes. Other,
less common, primitive markings include a shoulder stripe or shadow across the withers,
dark ear tips, shadowing on the neck, cobwebbing on the face, frosting in the mane and
tail, and mottling. These primitive markings will be the same color as the mane and tail,
although some may be very faint. A horse with the "dun" dilution gene will
rarely show dappling (circular splotches with lighter centers), however dappling is common
with the "c cr" dilution gene. There is more about the primitive markings at the
end of this article.
Although the primitive markings are associated with the "dun" dilution, it
may be possible that they can be inherited separately. More scientific study will probably
affirm or discredit this theory.
Since 1987 the AQHA has classified a horse with a dorsal stripe as a dun and a horse
without the dorsal stripe as a buckskin. This is opposite to the way they used to register
these colors, so you may, for example, find pedigrees showing a dun horse siring a
buckskin foal. There is also the possibility of a horse carrying a copy of each dilution
gene. In this case, it may be possible to have a palomino horse with a dorsal stripe.
Dorsal Stripe - The color of the stripe will depend on the body color - can vary
from black or dark brown to a sorrel or peach color.
Leg Barring - These are horizontal stripes across the hocks, inside and on the
front of hind legs, and on the back of the forearms and across the knees.
Shoulder Stripe or Shadowing - A stripe, or sometimes, several stripes, over the
withers in varying widths and lengths. Occasionally several stripes will merge together
giving a shadow effect.
Ear Tips - The tops and sometimes the sides of the ears are darker than the body
color. Occasionally there are also horizontal stripes on the backside of the ears.
Neck Shadowing - Occasionally dark shadows will appear on the crest of the neck
or extending into the hollow of the shoulder.
Cobwebbing - Lines of varying lengths over the forehead and face resembling a
spider web. Occasionally the lines extend from the eye somewhat like an eyebrow. Sometimes
the lines merge to look like shadows across the bridge of the nose or around the lips and
Mane and Tail Frosting - Light hairs in the mane or at the top of the tail. The
light hairs can run throughout the length of tail.
Mottling - Similar to dapples, however the mottling color is darker than the
body color (as opposed to the lighter dappling). Additionally the mottling is usually only
found on the forearms, shoulders, gaskins, and stifles, whereas dappling is usually on the
barrel and hips.