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Description

Dun - nD or DD - The Dun gene is a dilution gene that affects both red and black coat color pigments. The gene is associated with "primitive marking" and has the ability to affect the appearance of all black, bay, or chestnut ["red"]-based horses to some degree by lightening the base body coat.

The dark stripe down the middle of the animal's back is the most recognizable marking associated with Dun horses. Other markings include a tail and mane darker than the body coat and usually darker faces and legs. The classic Dun is a gray-gold or tan, characterized by a body color ranging from sandy yellow to reddish-brown. Depending on other underlying genetic coat color factors, a Dun horse may appear a light yellowish shade or a steel gray. Manes, tails, primitive markings and other dark areas are usually the shade of the non-diluted base coat color.

The Dun allele is dominant, meaning that a horse that carries either a single copy [heterozygous] or two copies [homozygous] of the gene will exhibit a dun phenotype. Unlike the silver dilution gene [which affects only black-based coats], the Dun gene affects both black and red-based horses.

The Dun dilution gene is characterized by markings which are darker than the body color. These markings include:

• The Dorsal stripe [stripe down the center of the back, along the spine], seen almost universally on all duns.

• Horizontal striping on the back of forelegs, common on most duns, though at times rather faint.

• Shoulder blade striping, the least commonly-seen of the primitive markings.

COLORS DETERMINED BY THE DUN GENE

“Primitive” Markings
The color determined by the Dun gene (Dn+ allele) in combination with the bay base color is genetically close to the color of the ancestors of the domestic horse, as well as contemporary wild representatives of the species. They are also typical for aboriginal species. Including this group of colors in the category of dilutions is only relative: The main characteristic of the color dun is the presence of the so-called “Wild” or “primitive” markings. The dilution of hair is only an additional feature, and it is not present or obvious in all cases. The following primitive markings are seen in horses with the Dun gene:

The dorsal stripe is a dark stripe that runs along the horse’s spine from the
withers to the dock of the tail. Its main characteristic is clearly defined boundaries. It is possible to liken it to a wide line drawn on the horse with a fat-tipped marker. Sometimes you can also see short transverse
stripes, which is called fish boning (or barbs) due to the similarity with a fish’s spine. Occasionally in horses with strong color dilution you can also find a zigzag-shaped or discontinuous dorsal stripe.

• Zebra bars or zebra stripes are short, dark, transverse stripes on the horse’s legs, located in or above the region of the knees and hocks. Zebra
bars are frequently present only on the backside of the legs.
• Often on the backside of the lower part of the horse’s legs, you will see a line of lighter hair, known by some as a zipper.
• Cob-webbing or lacing is a net of dark lines, which converge in the center of forehead of some dun horses, resembling a cobweb. This marking rarely involves the eye area.
• Many dun horses have dirty yellow, pale yellow, or even white strands of hair concentrated on the edges of the mane. Sometimes there can be so much frosting, as it is called, that the mane looks white. Although the latter
scenario is rare, it can create difficulty in determining the color of the animal.
• Frosting is frequently dark in summer and becomes more noticeable in winter. Frequently in addition to frosting in the mane, there is also light hair in the tail (light guard hair). It can be white or pale yellow and is located along the sides of the tail dock, concentrated at the base.
• Dark ear rims and white tips are present in almost all dun horses, spanning the perimeter of the ears. In contrast to the bay and brown horses, this primitive marking is wider and has clearer boundaries.
• When the lower part of the horse’s head, from the eyes to the nostrils, is darker than the forehead, neck, and body, he is said to have a mask. This
is most noticeable when the horse is observed from a distance, and in bay- or black-based horses. It can be less obvious when the horse has white head markings.
• Many horses have more or less noticeable darkening on the withers and shoulders in the form of a stripe or shadow (“wing”) perpendicular to the spine with poorly defined boundaries.
• A noticeable concentration of dark hair is often found on the neck near the
Mane.
• A ventral stripe along the horse’s underbelly resembles the dorsal stripe, but it runs down the middle of the abdomen parallel to the spine. Of all the primitive markings described here, the dorsal stripe is the only one “required” for the categorization of dun color. Zebra bars on the legs are common, but they may not be always noticeable against dark background hair. The remaining markings I’ve mentioned are encountered in different combinations and can be poorly visible. The color of primitive markings varies and depends on the color of a particular horse. They are usually the color of the horse’s guard hair.

Description

Dun - nD or DD - The Dun gene is a dilution gene that affects both red and black coat color pigments. The gene is associated with "primitive marking" and has the ability to affect the appearance of all black, bay, or chestnut ["red"]-based horses to some degree by lightening the base body coat.

The dark stripe down the middle of the animal's back is the most recognizable marking associated with Dun horses. Other markings include a tail and mane darker than the body coat and usually darker faces and legs. The classic Dun is a gray-gold or tan, characterized by a body color ranging from sandy yellow to reddish-brown. Depending on other underlying genetic coat color factors, a Dun horse may appear a light yellowish shade or a steel gray. Manes, tails, primitive markings and other dark areas are usually the shade of the non-diluted base coat color.

The Dun allele is dominant, meaning that a horse that carries either a single copy [heterozygous] or two copies [homozygous] of the gene will exhibit a dun phenotype. Unlike the silver dilution gene [which affects only black-based coats], the Dun gene affects both black and red-based horses.

The Dun dilution gene is characterized by markings which are darker than the body color. These markings include:

• The Dorsal stripe [stripe down the center of the back, along the spine], seen almost universally on all duns.

• Horizontal striping on the back of forelegs, common on most duns, though at times rather faint.

• Shoulder blade striping, the least commonly-seen of the primitive markings.

COLORS DETERMINED BY THE DUN GENE

“Primitive” Markings
The color determined by the Dun gene (Dn+ allele) in combination with the bay base color is genetically close to the color of the ancestors of the domestic horse, as well as contemporary wild representatives of the species. They are also typical for aboriginal species. Including this group of colors in the category of dilutions is only relative: The main characteristic of the color dun is the presence of the so-called “Wild” or “primitive” markings. The dilution of hair is only an additional feature, and it is not present or obvious in all cases. The following primitive markings are seen in horses with the Dun gene:

The dorsal stripe is a dark stripe that runs along the horse’s spine from the
withers to the dock of the tail. Its main characteristic is clearly defined boundaries. It is possible to liken it to a wide line drawn on the horse with a fat-tipped marker. Sometimes you can also see short transverse
stripes, which is called fish boning (or barbs) due to the similarity with a fish’s spine. Occasionally in horses with strong color dilution you can also find a zigzag-shaped or discontinuous dorsal stripe.

• Zebra bars or zebra stripes are short, dark, transverse stripes on the horse’s legs, located in or above the region of the knees and hocks. Zebra
bars are frequently present only on the backside of the legs.
• Often on the backside of the lower part of the horse’s legs, you will see a line of lighter hair, known by some as a zipper.
• Cob-webbing or lacing is a net of dark lines, which converge in the center of forehead of some dun horses, resembling a cobweb. This marking rarely involves the eye area.
• Many dun horses have dirty yellow, pale yellow, or even white strands of hair concentrated on the edges of the mane. Sometimes there can be so much frosting, as it is called, that the mane looks white. Although the latter
scenario is rare, it can create difficulty in determining the color of the animal.
• Frosting is frequently dark in summer and becomes more noticeable in winter. Frequently in addition to frosting in the mane, there is also light hair in the tail (light guard hair). It can be white or pale yellow and is located along the sides of the tail dock, concentrated at the base.
• Dark ear rims and white tips are present in almost all dun horses, spanning the perimeter of the ears. In contrast to the bay and brown horses, this primitive marking is wider and has clearer boundaries.
• When the lower part of the horse’s head, from the eyes to the nostrils, is darker than the forehead, neck, and body, he is said to have a mask. This
is most noticeable when the horse is observed from a distance, and in bay- or black-based horses. It can be less obvious when the horse has white head markings.
• Many horses have more or less noticeable darkening on the withers and shoulders in the form of a stripe or shadow (“wing”) perpendicular to the spine with poorly defined boundaries.
• A noticeable concentration of dark hair is often found on the neck near the
Mane.
• A ventral stripe along the horse’s underbelly resembles the dorsal stripe, but it runs down the middle of the abdomen parallel to the spine. Of all the primitive markings described here, the dorsal stripe is the only one “required” for the categorization of dun color. Zebra bars on the legs are common, but they may not be always noticeable against dark background hair. The remaining markings I’ve mentioned are encountered in different combinations and can be poorly visible. The color of primitive markings varies and depends on the color of a particular horse. They are usually the color of the horse’s guard hair.