What is a roan?
"Roan" refers to a horse coat color pattern characterized by a mixture of colored and white hairs on the body, while the head and "points"—lower legs, mane and tail—are mostly solid-colored. Horses with roan coats have white hairs evenly intermingled throughout any other color. The head, legs, mane and tail have fewer scattered white hairs or none at all. The roan pattern is dominantly-inherited, and is found in many horse breeds. While the specific mutation responsible for roan has not been exactly identified, a DNA test can determine zygosity for roan in several breeds. True roan is always present at birth, though it may be hard to see until after the foal coat sheds out. The coat may lighten or darken from winter to summer, but unlike the gray coat color, which also begins with intermixed white and colored hairs, roans do not become progressively lighter in color as they age.
The shades of roan
bay roan: base color bay
blue roan: base color black
red roan: base color sorrel
Horses with the roan pattern have an even mixture of white and colored hairs in the coat. These interspersed white hairs are more scattered or absent on the horse's head, mane, tail, and lower legs. The unaffected color on the legs often forms a sharp, inverted "V" above the knee and hock, not seen in other roan-like coat patterns. The non-white background coat may be any color, as determined by unrelated genetic factors.
Often, the background coat color is used in combination with the word "roan" to describe the shade of a roan horse's coat, such as bay roan or red roan.
The most common shades and terms for various roan colors are the following:
Blue roan: any roan with a dark underlying coat that gives it a bluish cast. However, "blue roan" is a roan with a black base color.
Red roan: "red roan" used to include both chestnut and bay roans. in 1999, the American Paint Horse Association changed its coat color descriptions: roans with a chestnut background coat are registered "red roan" while "bay roan" is its own category. The American Quarter Horse Association followed suit in 2003. Previously, the term strawberry roan described the pinkish color of a light chestnut or sorrel roan. While less common, the term lilac roan may be applied to a dark chestnut, and honey roan to palominos or the lightest sorrels.
Bay roan: "bay roan" replaced "red roan" as the term for a roan with a bay base color.
Three shades of Bay Roan
brown base color, black points
brown base color, black points
bay base color, black points,
white hair in mane and tail
Some roan horses have more white hair than others, and even individual horses may look lighter or darker based on the season and their coats may vary from year to year. While roan is always present at birth, the soft first coat of newborn foals may not show the white hairs well. Some roan horses get darker with age. Generally, roans appear to have more white hair when they have their short summer coats and darker when they have their winter coats.
Roans have other unusual characteristics. If the skin is damaged by even a very minor scrape, cut or brand, the coat grows back in solid-colored without any white hairs. These regions of solid-colored coat are called "corn spots" or "corn marks" and can appear even without the horse having had a visible injury.
Another true roan trait is reverse dappling. Usually dapples are darker than the surrounding coat color, but on a roan, the dapples are lighter.
More shades of roan
While bay roan, blue roan and red roan are the 3 main classifications and most typical shades of roan, roans can come in virtually any base color. In a lighter color horse, roan hairs may be harder to see, but the same mixture of colored hairs and white hairs apply.
When is a roan not a roan?
This is the same horse
registered a bay roan...
but turned gray with age.
Gray VS Roan
Roans are sometimes mistaken for grays, however horses can possess characteristics of both gray and roan. Gray is one of the most common coat colors found in nearly all breeds of horses. The defining characteristic of the gray coat is that it becomes progressively lighter over time. Gray foals may be born any color, even roan, and there may be no indication of the future gray coat at birth. Mature grays may retain none of their original coat color, and have a "white" coat, while the color of the skin and eyes is unchanged. The first white hairs are usually seen around the muzzle and eyes. As a gray may go from entirely colored to entirely white over the course of its life, the process of "graying out" can, at times, closely resemble roan. Unlike grays, roans without a graying gene do not develop more white hair with age, though than can appear lighter or darker seasonally.
Dun VS Roan
Grullo coloring is created by the dun gene, called the dun factor, acting on a black base coat. Grullo is a coat color with a bluish cast and darker points. Unlike blue roans, grullos have solid colored hairs and appear bluish due to low amounts of pigment in each hair, not black hairs interspersed white hairs. Like other dun factor coat colors like dun or red dun, grullos have dark or black primitive markings, always including a stripe down the back.
Rabicano VS Roan
One pattern of roaning is rabicano. While true roans have an even intermixture of white hairs throughout the body, except the extremities, the white hairs of a rabicano are densest around the base of the tail and the flank. Rabicano roaning frequently forms rings of white hair around the base of the tail, called a "coon tail" and in extensively roaned rabicanos, the white hairs may converge to form vertical stripes over the ribcage. Rabicano is found in many breeds but is not a recognized color in the AQHA. Rabicano horses are classified by their base color in most breeds.
Rabicano - bay with roan hair in flanks and a coon tail
Rabicano - sorrel with roan hairs over rib, hip and a coon tail
Roans in different breeds
Sabino VS Roan
Roaning is also associated with some of the sabino spotting patterns. There are many patterns in various breeds called "sabino," and these patterns usually feature irregular, rough-edged patches of white that originate from the lower legs, face, and midline. The borders of these white patches can be heavily roaned, and some sabinos can be mistaken for roans. The roaning of sabinos will originate in a white patch, and the roaning is uneven.
Varnish Roan VS Roan
The leopard complex colors, characteristic of the Appaloosa, have several manifestations that feature mixtures of white and colored hairs. A varnish roan, one type of leopard complex coat color also called "marble", is an all-over blend of white and colored hairs. Patches of skin that lie close to the bone, such as on the face and legs, and the point of shoulder and point of hip, do not grow as much white hair. These darker patches are called "varnish marks" and are not found in true roans. Varnish roans can also be distinguished from true roans by the presence of leopard complex characteristics, such as the white sclera, striped hooves, and mottled skin around the eyes, muzzle, and genitals.
Roan is a simple dominant trait symbolized by the Rn allele. Roaning, caused by the roan gene, (R), cannot appear in offspring of two non-roan parents, even if they have roan ancestors. The three primary base colors include red (chestnut “e” gene), black (“E” gene), and bay (Black “E” gene) +Agouti (“A”gene) which when paired with the roan gene result in the red or strawberry, blue, and bay roans, respectively.
Homozygous Roan horses have the genotype Rn/Rn and produce 100% roan offspring. Homozygous roans and heterozygous roans (Rn/rn) are identical in appearance.
Traits that are dominantly-inherited cannot skip generations, meaning that two non-roan parents cannot produce a roan offspring. In cases where roan has appeared to skip generations, one of the parents is usually discovered to be slightly roaned. A roan can also be born from two seemingly non-roan parents if the roan coat is "masked" by extensive white markings or gray. In some cases, the supposedly roan offspring is not true roan at all, but rabicano, sabino, or influenced by some other genetic factor.
The University of California, Davis School of Veterinary Medicine's genetics services developed a DNA test that uses genetic markers to indirectly determine the number of Rn or rn alleles a horse has. The mutation responsible for true roan has not yet been identified exactly, but been assigned to equine chromosome 3 (ECA3) in the KIT sequence. The roan zygosity test is reliable for American Quarter Horses and American Paint Horses. Until a direct test is developed, the roan zygosity test may enable breeders to produce roans more reliably.
The single way to be positive your horse has roan genetic markers is to have him genetically tested.