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Different meaning: Roan, Norway.

Roan is a type of coat color found most often in horses, but also other animals, including dogs and cattle. It is a mixture of white hairs together with a base coat of any darker color. Roan animals are born roan and the coat color remains relatively consistent throughout life.

Contents 1 Roan in Horses 2 Lethal Roan Question 3 Roan in Dogs 4 Roan Cattle 5 Roan Guinea Pigs 6 References 7 See also 8 External links

See also: Equine coat color genetics

Roan, caused by the roan gene, (R), consists of single white hairs intermingled with the base color of a horse. Roaning gives the horse a lightened appearance, while the mane, tail, head and legs tend to remain darker, close to the original base color. It is a dominant gene, meaning that any individual with at least one copy of the R gene trait will be roan. An implication of the gene's dominance is that at least one parent must be a roan in order to pass the gene on — it cannot appear in offspring of two non-roan parents, even if they have roan ancestors.

Roan horses are born roan and stay that way throughout life. Though there may be some changes in coat color when a foal sheds out its first "baby" coat, and color variation from summer to winter, but the horse will not progressively lighten each year the way a gray does. A roan and a gray can be distinguished from one another because a gray is born dark, and lightens more each year, usually on the head first, while a roan is born with intermixed hairs, and the head stays darker than the body.

The true roan gene appears in some breeds more than others. Roans are commonly found in Quarter Horses, American Saddlebreds, Tennessee Walking Horses, Connemara Ponies, Miniature horses, Welsh Ponies (though rarely, if ever, in Welsh Cobs) and Shetland Ponies.

The roan gene arguably does not appear in Arabians and Thoroughbreds; though horses in these breeds have been registered as "roan." It is thought that irregularly colored individuals in those breeds may actually carry the rabicano gene or the sabino gene complex rather than the "true" roan gene. In other cases, a young horse that was slow to turn gray was occasionally mistaken for a roan at the time of registration and the papers never corrected.

Several terms are used to describe different shades of roan in horses:

see also Equine coat color

• Red or Strawberry Roan Begins genetically with a chestnut (sometimes called sorrel) base coat with white intermingled hairs. Like a chestnut, the mane and tail are red. Some red roans have so many white hairs as to have a near-pinkish tint while others, tending toward rabicano coloring, may have only a few white hairs intermingled on an otherwise dark coat.
• Bay Roan Begins genetically with a bay base coat, giving a roan horse a reddish coat but black mane and tail, with dark "points" (ears and lower legs). The head will usually be red, with a black forelock. Bay Roans are sometimes also called red roans. ^[1]
• Blue Roan Begins genetically with a black base coat, intermingled with white hairs and the end result is a horse coat with a bluish tint. Blue roans are occasionally confused with grays or a blue . However, a gray becomes lighter with age and a blue roan does not. A blue dun (also known as a grullo) has a faded mouse-colored coat that is all one shade on the body (other than the distinctive dun markings), with no intermingled white hairs.

These shades of roan are created genetically as follows:

• Red base (chestnut "e" gene) + Roan = Red or Strawberry Roan
• Black base ("E" gene) + Roan = Blue Roan
• Bay base (Black ("E" gene) + Agouti "A" gene) + Roan = Bay Roan

Roan can also appear on any other base color or mixture of colors, so there are also buckskin roans, silver dapple roans, and so on. However, with dilution gene coat colors, the white hairs may not be as noticeable.

Varnish roan coloring seen in the Appaloosa is not caused by the roan gene, but is the result of the varnish roan gene combined with the leopard (lp) gene that creates the distinctive spotting patterns of the breed.

There was a theory that a homozygous roan (RR) could be a lethal gene. This idea of "Lethal Roan Syndrome" was based primarily on a 1979 study.^[2] This study examined the percentages of roan foals thrown by roan parents, and found fewer than expected. The study did not include direct genetic analysis, as such technology was not available at the time. Not finding large numbers of dead foals, the researchers concluded that any homozygous roan fetus was absorbed, thus preventing birth. This study and its conclusions popularized the idea of Lethal Roan Syndrome. This was consistent with the "dominant white" and "lethal white" studies available at the time; later study has shown that the dominant white or "W" gene in horses is lethal when homozygous (see White (horse), and there is a different, unrelated recessive condition called lethal white syndrome. Nonetheless, in the late 1970s, genetic science had not yet developed to provide a clear answer to the roan question.

A more recent genetic study of roans by Dr. Ann Bowling refuted the lethal roan theory. Using modern genetic analysis techniques, Dr. Bowling found several homozygous roans and no evidence of a Lethal Roan Syndrome.^[3]

The roan gene in dogs acts as a simple dominant gene. The action of the gene results in a mingling of colored and white hairs. To be roan a dog must have white areas; a solid colored dog can not be roan. Breeds where the roan gene commonly occurs are English Cocker Spaniels, English Setters, and German Shorthaired Pointers. The roan pattern also occurs in American Cocker Spaniels, Field Spaniels, Lagotto Romagnolos and Border Collies.

Roan dogs are more prone to deafness due to the absence of pigment during ear formation. There are no other health issues associated with this gene.

Black and white roans are referred to as "blue roans" (spaniels) or "blue belton" (English Setters). Red/buff and white roans are referred to as "red roans" "orange roans" or "lemon roans" or oran. Brown and white are referred to as "liver roans", "chocolate roans" or "brown roans".

The roan color can also occur in Shorthorn Cattle, but is genetically a result of intermediate inheritance or Co-dominance. They cannot pass on the color directly, as this type of intermediate inheritance is also heterozygous, requiring two different color alleles, one from each parent, to produce this particular coat coloring.

Special attention is paid by breeders to the roan coloration of Guinea pigs, as they have developed fatal deformities in the past.

1. ^ AQHA General Glossary
2. ^ Hintz, H.F. and VanVleck, L.D., published 1979. Lethal Dominant Roan in Horses. Journal of Heredity 70:145-146.
3. ^ http://www.hancockhorses.com/article-roanQHNews.pdf QH News

• Bowling, Ann T. "Coat Color Genetics: Positive Horse Identification" from Veterinary Genetics Laboratory, School of Veterinary Medicine, University of California, Davis. Web site accessed February 9, 2007

• Equine coat color genetics
• Equine coat color

Horses

• Photo of blue roan
• Photo of grulla roan
• Photo of chestnut roan
• Photo of smoky black roan (black + 1 creme gene + roan)
• Photo of palomino roan
• Photo of silver dapple roan
• Photo of strawberry roan
• Photo of bay roan
• Horse Coat Color Genetics (Including roan definition, photos, and genetic formulas)
• Blue Roan Genetics and Photos

Dogs

• Photos of roan English Cockers
• Photos of roan Australian Cattle dogs
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