Rabicano

Rabicano, sometimes called white ticking, is a horse coat color characterized by limited roaning in a specific pattern: its most minimal form is expressed by white hairs at the top of a horse's tail,[1] often is expressed by additional interspersed white hairs seen first at the flank, then other parts of the body radiating out from the flank, where the white hairs will be most pronounced.[2] Rabicano is distinct from true roan, which causes evenly interspersed white hairs throughout the body, except for solid-colored head and legs.[1]

An extensively expressed rabicano purebred Arabian horse. (Photo courtesy of Amentaah Egyptian Arabians).

Etymology

The word "rabicano" is of Spanish origin - rabo meaning "tail" and cano meaning "white" - thus, it described a horse with white hairs in its tail.[3] The word appears very early in epic poems in Italian literature: Argalia, a character in Orlando Innamorato (1495), rides a horse named "Rabicano". So too does Astolfo. In Italian, the term simply means "roan" and might therefore have been a descriptive name.

Characteristics
This chestnut rabicano has white hairs arranged in bands or rings around the base of the tail, a trait called a coon tail or skunk tail

The characteristics most often associated with the rabicano pattern are white hairs at the tailhead and the flank, where the body of the horse is joined by the hindquarters.[4] Like other patterns and colors, the expression of the rabicano trait varies. Most of the factors affecting these variations are unknown, however, it is known that horses with a chestnut or chestnut-based coat express white patterns such as rabicano more readily; that is, they tend to have more white. Minimal expression may include a few white hairs in those areas, but is often not mentioned in descriptions of an individual horse's color.[4] Rabicano is a white pattern that falls into the category of roaning or scattered white hairs, the genetics of which are not yet fully understood,[5] but are apparently a different genetic mechanism from true roan.[1]

The original definition of "rabicano" referred to the presence of white hairs in the base of the tail, a characteristic called a "skunk" or coon tail.[6] The term "coon tail" is associated with white hairs in the form of striping at the tailhead.[4] The sides of the tail at the tailhead may have much white hair. Extensively marked rabicanos sometimes exhibit striations in their pattern on the ribs, giving them a striped appearance.[7]

Prevalence and inheritance
Rabicano on a bay most often is exhibited on the mane and tail
"Skunk tail" white hairs on a bay horse

The rabicano pattern is thought to be a dominant gene in some families,[4] however other forms of white ticking not following the rabicano pattern may exist and be controlled by separate mechanisms. Rabicano is present even in breeds which do not possess any true roan individuals, such as Arabian horses.[8][9] In the Arabian, Rabicano patterning is even defined as "roan."[4] Rabicano may occur on any base color and may occur in conjunction with any other white pattern, including true roan or gray.

Higher expression of the rabicano pattern on the flanks may produce a coat easy to mistake for true roan. However, in highly expressed rabicanos, the distribution of white hairs along the barrel may produce faint striping or stippling over the ribs, which is not seen in true roans. Furthermore, the skin of some rabicanos may be slightly mottled with pink, particularly on the abdomen and groin.[10] This trait is not seen in true roans, and suggests that, like the white hairs associated with other white markings and patterns, the white hairs of a rabicano may be rooted in unpigmented skin cells. However, the genetic and developmental controls of such roaning are poorly understood,[11] and has not yet been formally studied.[4]

While rabicano itself does not produce white markings on the face and legs, it can be confused with some of the numerous sabino patterns, one of which has been mapped to the KIT gene. Other color patterns mapped to KIT include tobiano and true roan.[12][13][14] This may explain the close association between rabicano and sabino, which are often observed in the same horse.

Vs. roan
See also: Roan horse
This horse could be either roan or rabicano; lack of white hairs on forehand and presence of skunk tail suggest rabicano, but overall body pattern is more typical of a roan.

Rarely is rabicano patterning extensive enough to be confused with true roan.[4] It is, however, possible for a horse to carry both rabicano and roan genes.[1] Rabicanos are not true roans and can be distinguished from true roans by the following:

  • Roaning on rabicanos is centralized at the junction of the stifle and the flank; true roan is evenly distributed over the whole body except the points.
  • Rabicanos usually have skunk tails or rings of white hairs in the tail, while true roans do not.
  • Rabicano roaning often spreads, while true roans usually become darker.
  • Rabicanos do not develop corn marks when their skin is damaged.

Vs. sabino
See also: Sabino horse

Sabino patterning usually is expressed with high white legs markings with white sometimes extending onto the belly, face, and chin; sabinos often lack the white hairs at the base of the tail that characterize rabicano. A horse may carry the genes for both patterns, however.[1]

See also

References
  1. Caudill, Andrea (25 July 2010). "Skunk Tailed". America's Horse Daily. America's Horse Daily. Archived from the original on 22 September 2010. Retrieved 28 January 2014.
  2. Price, Steven D.; Jessie Shiers; William Steinkraus (2007). The Lyons Press Horseman's Dictionary: Full Explanations of More than 2,000 Terms and Phrases Used by Horsemen. Don Burt. Globe Pequot. p. 175. ISBN 1-59921-036-3. rabicano: A coat color in which a few, scattered white hairs appear amid a darker-colored background, usually on the hindquarters and dock
  3. Juan de la Cruz Puig. Antologia de Poetas Argentinos,1910. pg. 131. "Rabicano: caballo que tiene cerdas blancas á la raíz de la cola." [Rabicano: a horse that has white hairs at the root of the tail]
  4. Sponenberg, Dan Phillip (2003-04-11). "4/Patterns of White Occurring on Base Colors". Equine Coat Color Genetics (2 ed.). Wiley-Blackwell. p. 69. ISBN 978-0-8138-0759-1. Retrieved 2008-08-03.
  5. Veterinary Genetics Laboratory. "Introduction to Coat Color Genetics". The Regents of the University of California. Retrieved 2008-06-04.
  6. Behning, Laura. "Rabicano, Roan, Flaxen, and Frame Overo Morgan Horses". Morgan Colors. Archived from the original on 2008-09-14. Retrieved 2008-08-03.
  7. Peters, Anne (2002-05-04). "A roan by any other name is a roan". Thoroughbred Times. Lexington: Thoroughbred Times Co. Inc. Retrieved 2008-06-04.
  8. Sponenberg 2003, p. 70, indicates that roan has reappeared in Thoroughbreds via a new mutation in a single horse
  9. Overton, Rebecca (2004-12-15). "In The Genes" (PDF). Quarter Horse News. American Quarter Horse Association. pp. 24–6. Archived from the original (PDF) on 2007-09-27. Retrieved 2008-06-04.
  10. B. Kostelnik. "Rabicano". The Horse Colors Site. Hippo-Logistics. Retrieved 2008-08-03.
  11. "Introduction to Coat Color Genetics". UC Davis. Retrieved 2008-08-03. The inheritance of scattered white hairs, sometimes called roaning, is not defined.
  12. Marklund, S; M Moller; K Sandberg; L Andersson (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. PMID 10051325.
  13. brooks, SA; TL Lear; DL Adelson; E Bailey (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. PMID 18253033.
  14. Andersson, L; K Sandberg (March 1982). "A linkage group composed of three coat color genes and three serum protein loci in horses". Journal of Heredity. 73 (2): 91–4. PMID 7096983.
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