Tobiano
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Tobiano is a genetic trait among Pinto horses which produce a characteristic spotting pattern in the coat of the horse. The tobiano gene produces areas of white-haired, pink-skinned patches on a base coat color. The coloration is present from birth and does not change throughout the horse's lifetime. (Unless the horse also carries the gray gene, see below)
Tobiano traits generally include the following:
- White legs from the hocks and knees down
- White crossing the back between the withers and the dock of the tail
- White is arranged in a vertical pattern
- Facial markings like that of a solid-colored horse. i.e. star, snip, strip, or blaze
- White patches which are usually rounded or oval in shape, rather than jagged (see Overo)
- Dark color extending down the neck, giving the appearance of a shield
The coat pattern can occur when only a single heterozygous gene is present, because Tobiano is a dominant gene. When a horse is homozygous for Tobiano coloring, that horse's offspring will almost always be spotted unless the horse also carries the gray gene, in which case, the horse's spots will only be visible while it is young, eventually becoming lighter until finally, as the gray gene acts upon all coat colors, fade to pure white.
The Tobiano gene is not linked to lethal white syndrome. However, some Tobiano horses with ancestors of other backgrounds have been silent carriers of the gene and have produced affected offspring.[1]
In the UK, tobianos are frequently referred to as Piebald or Skewbald, depending on base coat color. Other spotting patterns seen in Pinto horses include overo and the sabino markings.
[edit] References
- ^ Paul D. Vrotsos RVT and Elizabeth M. Santschi DVM. University of Minnesota Genetics Group. "Stalking the Lethal White Syndrome". Paint Horse Journal. July 1998.
- 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
