Created at the VGL Roan Zygosity Test

Quick Summary

Roan is a white patterning coat color trait characterized by intermixed white and colored hairs in the body while the head, lower legs, mane, and tail remain colored.

classic_roan_example
Horse with the classic roan pattern on a bay base coat color

Phenotype: Roan is a white patterning coat color trait characterized by intermixed white and colored hairs in the body while the head, lower legs, mane, and tail remain colored.

Mode of Inheritance: Autosomal dominant

Alleles: N = Normal, Rn = Classic Roan

Breeds appropriate for testing: Many breeds

Explanation of Results:

  • Horses with N/N genotype will not have the classic roan pattern and cannot transmit this roan variant to their offspring.
  • Horses with N/Rn genotype will have the classic roan pattern. They may transmit this roan variant to 50% of their offspring. Matings with N/N genotype will result in a 50% chance of producing a roan foal.
  • Horses with Rn/Rn genotype will have the classic roan pattern. They will transmit this roan variant to all of their offspring. Matings with any genotype are predicted to produce all roan offspring.
Price

$40 one test per animal

Additional Details

Horses with the roan pattern on different coat color bases
Classic roan pattern on different base coat colors. Clockwise from top: A. roan on a black base, aka "blue roan"; B. roan on a grullo (black base plus dun dilution); C. roan on a bay base; D. roan on a chestnut base, aka "strawberry roan". Image credits: A courtesy of Dan Elkins, from Equine Color Genetics, 4th Edition; B & D by Sheila Archer; C by JoAnn Bellone.

Roan is a white patterning coat color trait of intermixed white and colored hairs in the body while the head, lower legs, mane, and tail remain colored. Roan horses are born with the pattern, though it may not be obvious until the foal coat is shed. The white and colored hairs are evenly mixed in horses that inherit the classic Roan gene, which can differentiate this from several mimic patterns called roaning. Roaning patterns tend to be uneven in the distribution of white hairs, and the inheritance of roaning has not been defined. The Roan gene is found in a variety of breeds such as Quarter Horse, Paints, Peruvian Paso, Paso Fino, Welsh Pony, Miniature and Belgian, but not in Thoroughbreds or Arabians.

Although it has been suggested that Roan is a homozygous lethal, evidence from the Quarter Horse breed indicates otherwise. Production records have documented the existence of Roan Quarter Horses that produce 100% Roan foals. DNA tests have confirmed homozygosity in the genomic region that contains the Roan gene.

Note: Roan is inherited as a dominant gene but the specific mutation has not yet been identified, so there is no direct test for the gene. VGL has identified DNA markers in Quarter Horses and Paints associated with Roan that can be used to determine if a horse has the roan gene and how many copies. The following additional materials should be included to provide a complete analysis:

Materials Needed for Complete Analysis

  1. Hair sample from at least one parent
  2. Color photo of the subject horse, labeled with the horse’s name
  3. Three generation pedigree with color and patterns listed

Closeup of intermixed white and colored hairs on a classic roan horse
Mixture of white and colored hairs on the body of a horse with the classic roan pattern

Turnaround Time
5-10 business days
Type of Sample

Species

Breed

Crossbred Unknown Akhal Teke American Sport Horse American Sport Pony American Warmblood Andadura Andalusian Appalachian Singlefoot Appaloosa Appendix Arriador Australian Stock Horse Azteca Baden-Wurttemberg Barockpinto Baroque Pinto Bashkir Curly Bavarian Belgian Belgian Sport Horse Belgian Warmblood Brandenburg British Sport Horse Bucking Horse Caballo Deportivo la Silla Canadian Horse Canadian Warmblood Caspian Horse Chilean Horse Clydesdale Connemara Pony Continental Warmblood Costa Rican Paso Horse Cream Draft Criollo Curly Dales Pony Danish Warmblood Deutsches Reitpony Deutsches Sportpferd Draft Cross Dutch Harness Horse Dutch Warmblood Exmoor Pony Falabella Fell Pony Finnhorse Frederiksborg French Warmblood "Selle Francais" Georgian Grande German Riding Pony Gotland Pony Gypsian Gypsy Cob Gypsy Vanner Hackney Horse Hackney Pony Half Andalusian Half-Marchador Hanoverian Hessen Hibrido Holsteiner Iberian Warmblood Iceland Pony Icelandic Horse Imperial Heritage Horse Sporthorse International Sport Pony Irish Draught Irish Hunter Kallblodstravare Kentucky Mountain Horse Kerry Bog Pony Kiger Mustang Knabstrupper Latvian Warmblood Lipizzaner Lusitano Mangalarga Mangalarga Marchador Mexican Sport Horse Miniature Horse Missouri Fox Trotter Mongolian Domestic Horse Morab Morgan Horse Moroccan Barb Mountain Pleasure Horse Mule Mustang National Show Horse Newfoundland Pony Nokota North American Trakehner Oldenburg Other Paint Horse Paso Fino Percheron Performance Horse Int'l Peruvian Paso Pinto Polish Warmblood Pony of the Americas Pura Raza Española Quarter Horse Racking Horse Rheinland Rheinland Pfaltz-Saar Rocky Mountain Horse Russian Orloff Russian Warmblood Saddlebred Scottish Highland Pony Shetland Pony Shire Shire Crossbred Sillo Argentino Single-Footing Horse Spanish Barb Spanish Heritage Horse Spanish Mustang Spotted Saddle Horse Standardbred Swedish Warmblood Tarpan Tennessee Walking Horse Thailand Pony Thoroughbred Trakehner Trocha Trocha y Galope Trote y Galope Uruguayan Criollo Virginia Warmblood Warlander Welsh Pony Welsh Pony Weser Ems Ponies Westfalen Wild Horse Zangersheide British Spotted Pony Noriker Ardennes Norwegian Nordland Breton Comtois New Forest Pony Cob Normand Rhenish German Coldblood South German Coldblood Saxon-Thuringian Coldblood
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Type of Test

Results Reported As
Test Result Classic Roan
N/N No copies of classic roan detected.
N/Rn 1 copy of classic roan detected. Horse will have the classic roan pattern.
Rn/Rn 2 copies of classic roan detected. Horse will have the classic roan pattern.
References

Sponenberg, D. P., Harper, H. T., & Harpar, A. L. (1984). Direct evidence for linkage of roan and extension loci in Belgian horses. Journal of Heredity, 75(5), 413-414. doi: 10.1093/oxfordjournals.jhered.a109968

Marklund, S., Moller, M., Sandberg, K., & Andersson, L. (1999). Close association between sequence polymorphism in the KIT gene and the roan coat color in horses. Mammalian Genome, 10(3), 283-288. doi: 10.1007/s003359900987