Tobiano

Quick Summary

Tobiano is a white spotting pattern characterized by white on the body that crosses the topline.

Tobiano Example
Foal homozygous for the tobiano pattern (TO/TO genotype). Image credit: Lucy Nold

Phenotype: Tobiano is a white spotting pattern characterized by patches of white that typically cross the topline somewhere between the ears and tail. These white ares are generally regular and distinct vertical patterns. Usually, unless there are other white patterning genes involved, the head is colored. 

Mode of Inheritance: Autosomal dominant

Alleles: N = Normal or non-tobiano, TO = Tobiano

Breeds appropriate for testing: Many breeds

Explanation of Results:

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

$25 one test per animal

Panels Available
Additional Details

The tobiano white spotting pattern is a trait controlled by a dominant allele. The pattern, like all white spotting patterns in the horse, can range in the amount of white but is generally characterized by white patches crossing the topline somewhere between the ears and tail. The skin underlying the white spots is pink and under the pigmented areas it is black. The eyes are usually brown, but one or both may be blue or partially blue. The head is typically dark, with white markings like those of a solid-colored horse, unless other white spotting genes are contributing. Usually, all four legs are white below the hocks and knees. The tail can be two colors—a characteristic seldom seen in horses that are not tobiano.

The tobiano gene has two alternative states (alleles). The dominant allele, TO, produces the tobiano pattern and the recessive allele, called "N" by VGL but "to" by others, is non-tobiano. A horse that is homozygous for tobiano, symbolized as (TO/TO), will always produce offspring that are tobiano regardless of the mate. For breeders interested in producing tobiano foals, a horse that is homozygous for tobiano is desirable in a breeding program.

Unlike other white spotting patterns caused by specific changes in DNA sequence of the genes, tobiano is associated with a large chromosome inversion that likely affects the function of the pigmentation gene KIT. The inversion associated with the tobiano pattern was identified by researchers at the University of Kentucky.

Testing for tobiano can assist in mate selection for this pattern.

Turnaround Time
At least 15 business days
Type of Sample

Species

Breed

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

Results Reported As
Test Result Tobiano
N/N No copies of tobiano detected.
N/TO

1 copy of tobiano detected.

TO/TO

2 copies of tobiano detected.

References

Brooks, S., Lear, T., Adelson, D., & Bailey, E. (2007). A chromosome inversion near the KIT gene and the Tobiano spotting pattern in horses. Cytogenetic and Genome Research, 119(3-4), 225-230. doi: 10.1159/000112065

License Info

This test is performed under a license agreement with the University of Kentucky.