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Roan is a type of coat color found most often in Horse s, but also other animals, including Dog s and Cattle . Is is a mixture of white hairs together with a base coat of any darker color. ROAN IN HORSES 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 Horse s, American Saddlebred s, Tennessee Walking Horse s, Connemara Ponies , Miniature Horse s, Welsh Ponies (though rarely, if ever, in Welsh Cob s) and Shetland Ponies . The roan gene arguably does not appear in Arabian s and Thoroughbred s; 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
These shades of roan are created Genetically as follows:
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. LETHAL ROAN QUESTION There was a theory that a , 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.http://www.hancockhorses.com/article-roanQHNews.pdf QH News ROAN IN DOGS 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 Spaniel s, English Setter s, Australian Cattle Dog s, and German Shorthaired Pointer s. The roan pattern also occurs in American Cocker Spaniel s, Field Spaniel s, Lagotto Romagnolo s and Border Collie s. 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" ( Spaniel s) or "blue belton" ( English Setter s). 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". ROAN CATTLE 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 Allele s, one from each parent, to produce this particular coat coloring. ROAN GUINEA PIGS Special attention is paid by breeders to the Roan Coloration of Guinea Pig s, as they have developed fatal deformities in the past. REFERENCES
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