Patterns
- Tobiano: The most common type of pinto, tobiano is a spotting pattern characterized by rounded markings with white legs and white across the back between the withers and the dock of the tail, usually arranged in a roughly vertical pattern and more white than dark, though the ideal is a 50-50 distribution, with the head usually dark, having markings also seen on a non-pinto horse. i.e. star, snip, strip, or blaze. Tobiano is a simple dominant trait caused by a single gene and therefore all tobiano horses have at least one tobiano parent. A DNA test exists for tobiano. Tobiano is not associated with any health concerns.
- Overo: A collective term used primarily by the American Paint Horse Association (APHA), overo essentially means "pinto, but not tobiano." It denotes patterns produced by at least three different genetic mechanisms: frame, splashed white or sabino, described below. These patterns are usually characterized by irregular markings with more jagged edges than tobiano markings. The white rarely crosses the back. While some currently-identified overo patterns appear to be dominant or incomplete dominant traits, overo-patterned foals (called "cropouts") are occasionally produced from two apparently solid-colored parents.
- Frame or frame overo: Frame is a popular and easily recognized type of non-tobiano pinto. This spotting pattern, in the absence of genes for other patterns, is characterized by horizontally-oriented white patches with jagged, crisp edges. White patches typically include the head, face and lateral aspects of the neck and body, and the eyes can be blue. Frame overos may have very modest markings that are not obviously "pinto." This quality allows the pattern to seemingly "hide" for generations, and is thought to be responsible for some cases of "cropouts." Frame is an incomplete dominant trait for which there is a DNA test; those without any copies of the "frame gene" (N/N) will not possess this pattern, while those with a single copy (N/O) usually exhibit frame patterning (though sometimes in a very minimal form). However, foals born with two copies (O/O) have lethal white syndrome and die shortly after birth. N/O frame horses do not have any known health defects, but have a 25% chance of producing lethal white foals if bred to another N/O horse.
- Splashed white: A less-common type of non-tobiano pinto pattern, splashed white coats have horizontally-oriented white markings with crisp, smooth edges and make the horse appear to have been dipped, head lowered, into white paint. The face has significant white markings, and the eyes are usually blue. Most splashed white pintos have normal hearing, but the trait is linked to congenital deafness. In Europe, some patterns identified as sabino in the USA are called "splash," particularly in the Icelandic horse.
- Sabino: Sometimes confused with roan or rabicano, sabino horses possess a slight spotting pattern characterized by high white on legs, belly spots, and white markings on the face extending past the eyes. The edges of markings may be "lacy" or there can be patches of roaning patterns standing alone or on the edges of white markings. Some forms of the sabino phenotype are thought to be polygenic or a gene complex. However, one form for which there is a DNA test, the sabino-1 (SB1) gene, is a dominant. Horses homozygous for SB-1 are often completely white. Sabino-1 and other sabino patterns are not associated with any health defects. Though genetically unrelated to frame or splash, sabino is classified with the "overo" family of patterns by the APHA. Sabino is not necessarily classified as an overo pattern by other breed registries, particularly those whose horses do not carry the genes for other pinto patterns.
- Tovero: The tovero spotting pattern is a mix of tobiano and any form of overo coloration, usually reflecting that the horse carries more than one set of genes for a spotting pattern. For example, a tovero may have a mostly white tobiano pattern on the body, but also have blue eyes with or without a white head. Horses can carry multiple spotting genes at the same time, producing characteristics of several patterns.
- Dominant white: A family of sabino-like white spotting patterns, all dominant white coats are dominantly inherited, analogous to human piebaldism. While some forms are associated with pure white coats and are considered "true white," not pinto, most actually show great variance in the amount of white. The 11 known forms of dominant white have all occurred spontaneously in the past century from non-white parents. Many forms of white spotting that were called "sabino" by their owners and fanciers are now classified as dominant white. The distinction between sabino and dominant white is unclear, as they are visually similar and involve closely related genes.
Read more about this topic: Pinto Horse, Color Patterns and Genetics of Pinto Horses
Famous quotes containing the word patterns:
“For the man who should loose me is dead,
Fighting with the Duke in Flanders,
In a pattern called a war.
Christ! What are patterns for?”
—Amy Lowell (1874–1925)
“One can describe a landscape in many different words and sentences, but one would not normally cut up a picture of a landscape and rearrange it in different patterns in order to describe it in different ways. Because a photograph is not composed of discrete units strung out in a linear row of meaningful pieces, we do not understand it by looking at one element after another in a set sequence. The photograph is understood in one act of seeing; it is perceived in a gestalt.”
—Joshua Meyrowitz, U.S. educator, media critic. “The Blurring of Public and Private Behaviors,” No Sense of Place: The Impact of Electronic Media on Social Behavior, Oxford University Press (1985)
“I’ve begun to appreciate the generational patterns that ripple out from our lives like stones dropped in water, pulsing outward even after we are gone. Although we have but one childhood, we relive it first through our children’s and then our grandchildren’s eyes.”
—Anne Cassidy (20th century)