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Equine Vision
The equine eye is one of the largest of any land mammal. Its visual abilities are directly related to the animal's behavior; for example, it is active during both day and night, and it is a prey animal. Both the strengths and weaknesses of the horse's visual abilities should be taken into consideration when training the animal, as an understanding of the horse's eye can help to discover why the animal behaves the way it does in various situations. Anatomy The equine eye includes the eyeball and the surrounding muscles and structures, termed the adnexa. Eyeball The eyeball of the horse is not perfectly spherical, but rather is flattened anterior to posterior. However, research has found the horse does not have a ramped retina, as was once thought. The wall of the eye is made up of three layers: the internal or nervous tunic, the vascular tunic, and the fibrous tunic. * The nervous tunic (or retina) is made up of cells which are extensions of the brain, coming off the optic nerv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elastin
Elastin is a protein encoded by the ''ELN'' gene in humans and several other animals. Elastin is a key component in the extracellular matrix of gnathostomes (jawed vertebrates). It is highly Elasticity (physics), elastic and present in connective tissue of the body to resume its shape after stretching or contracting. Elastin helps skin return to its original position whence poked or pinched. Elastin is also in important load-bearing tissue of vertebrates and used in places where storage of mechanical energy is required. Function The ''ELN'' gene encodes a protein that is one of the two components of elastic fibers. The encoded protein is rich in hydrophobic amino acids such as glycine and proline, which form mobile hydrophobic regions bounded by crosslinks between lysine residues. Multiple transcript variants encoding different isoforms have been found for this gene. Elastin's soluble precursor is tropoelastin. Mechanism of elastic recoil The characterization of disorder is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palomino
Palomino is a equine coat color, genetic color in horses, consisting of a gold coat and white mane (horse), mane and tail; the degree of whiteness can vary from bright white to yellow. The palomino color derived from the breeding of Spanish horses in the United States. Genetically, the palomino color is created by a single allele of a dilution gene called the cream gene working on a "red" (chestnut (coat), chestnut) base coat. Palomino is created by a genetic mechanism of incomplete dominance, hence it is not considered true-breeding. However, most color breed registries that record palomino horses were founded before equine coat color genetics were understood as well as they are today, therefore the standard definition of a palomino is based on the visible coat color, not heritability nor the underlying presence of the dilution gene. Due to their distinct color, palominos stand out in a show ring, and are much sought after as parade horses. They were particularly popular in m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterozygous
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same locus (genetics), loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal Sex-determination system#Chromosomal determination, sex-determination system. If both alleles of a diploid organism are the same, the organism is #Homozygous, homozygous at that locus. If they are different, the organism is #Heterozygous, heterozygous at that locus. If one allele is missing, it is #Hemizygous, hemizygous, and, if both alleles are missing, it is #Nullizygous, nullizygous. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dilution Gene
A dilution gene is any one of a number of genes that act to create a lighter coat color in living creatures. There are many examples of such genes: General Diluted coat colors have melanocytes, but vary from darker colors due to the concentration or type of these pigment-producing cells, not their absence. Pigment dilution, sometimes referred to as hypomelanism, has been called leucism, albinism (perfect, impartial, or dilute), ghosting, paling, and isabellinism. *Albinism describes a condition where pigment cells synthesize little or no pigment *Leucism describes a condition that creates loss of pigment cells Cats Cat coat genetics discusses many dilution genes in cats. Dogs In dogs, a mutation of the ''MLPH'' locus known as the dilute gene causes eumelanin to lighten while pheomelanin remains almost unchanged. Dogs of some breeds with the dilute gene often suffer from colour dilution alopecia (CDA). Appearance Of the colour shades found in the coat of dogs, the light brown ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cream Gene
The cream gene is responsible for a number of Equine coat color, horse coat colors. Horses that have the cream gene in addition to a base coat color that is chestnut (coat), chestnut will become palomino if they are heterozygous, having one copy of the cream gene, or cremello, if they are homozygous. Similarly, horses with a Bay (horse), bay base coat and the cream gene will be Buckskin (horse), buckskin or perlino. A black base coat with the cream gene becomes the not-always-recognized smoky black or a smoky cream. Cream horses, even those with blue eyes, are not white (horse), white horses. Dilution coloring is also not related to any of the Pinto horse, white spotting patterns. The cream gene (''CCr'') is an Dominance relationship, incomplete dominant allele with a distinct dosage effect. The DNA sequence responsible for the cream colors is the cream allele, which is at a specific Locus (genetics), locus on the SLC45A2, solute carrier family 45 member 2 (''SLC45A2'') ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homozygous
Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Most eukaryotes have two matching sets of chromosomes; that is, they are diploid. Diploid organisms have the same loci on each of their two sets of homologous chromosomes except that the sequences at these loci may differ between the two chromosomes in a matching pair and that a few chromosomes may be mismatched as part of a chromosomal sex-determination system. If both alleles of a diploid organism are the same, the organism is homozygous at that locus. If they are different, the organism is heterozygous at that locus. If one allele is missing, it is hemizygous, and, if both alleles are missing, it is nullizygous. The DNA sequence of a gene often varies from one individual to another. These gene variants are called alleles. While some ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heterochromia
Heterochromia is a variation in coloration most often used to describe color differences of the iris, but can also be applied to color variation of hair or skin. Heterochromia is determined by the production, delivery, and concentration of melanin (a pigment). It may be inherited, or caused by genetic mosaicism, chimerism, disease, or injury. It occurs in humans and certain breeds of domesticated animals. Heterochromia of the eye is called heterochromia iridum (heterochromia between the two eyes) or heterochromia iridis (heterochromia within one eye). It can be complete, sectoral, or central. In complete heterochromia, one iris is a different color from the other. In sectoral heterochromia, part of one iris is a different color from its remainder. In central heterochromia, there is a ring around the pupil or possibly spikes of different colors radiating from the pupil. Though multiple causes have been posited, the scientific consensus is that a lack of genetic diversity is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sabino Horse
file:Sabino-Pinto-Puerto-Rican-Paso-Fino.jpg, A sabino horse with extensive roaning Sabino describes a distinct pattern of white spotting in horses. In general, Sabino patterning is visually recognized by roaning or irregular edges of horse markings, white markings, belly spots, white extending past the eyes or onto the chin, white above the knees or hocks, and "splash" or "lacy" marks anywhere on the body. Some sabinos have patches of roan (horse), roan patterning on part of the body, especially the barrel and flanks. Some sabinos may have a dark leg or two, but many have four white legs. Sabino patterns may range from slightly bold face or leg horse markings, white markings—as little as white on the chin or lower lip—to horses that are fully white. The known causes of the sabino patterns are the SB-1 allele and several other dominant white#Allelic_series, dominant white (W) alleles on the KIT (gene), ''KIT'' gene. The genetics behind some types of sabino, such as that fou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overo
Overo refers to several genetically unrelated pinto coloration patterns of white-over-dark body markings in horses, and is a term used by the American Paint Horse Association to classify a set of pinto patterns that are not tobiano. ''Overo'' is a Spanish word, originally meaning "like an egg".''American Paint Horse Association's Guide to Coat Color Genetics'' American Paint Horse Association, 2007. Accessed August 19, 2008 The most common usage refers to frame overo, but and [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Splashed White
Splashed white or splash is a horse coat color pattern in the " overo" group of spotting patterns that produces pink-skinned, white markings. Many splashed whites have very modest markings, while others have the distinctive "dipped in white paint" pattern. Blue eyes are a hallmark of the pattern, and splash may account for otherwise "solid" blue-eyed horses. Splashed white occurs in a variety of geographically divergent breeds, from Morgans in North America to Kathiawari horses in India. The splashed white pattern is also associated with Hearing impairment, congenital deafness, though most splashed whites have normal hearing. Splashed white can be caused by multiple variants across two different genes, for which genetic testing is available. Characteristics The splashed white pattern is characterized by the appearance of having been dipped, feet-first, into white paint. Blue eyes An eye is a sensory organ that allows an organism to perceive visual information. It dete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pinto Horse
A pinto horse has a coat color that consists of large patches of white and any other color. Pinto coloration is also called paint, particolored, or in nations that use British English, simply coloured. Pinto horses have been around since shortly after the domestication of the horse. Pinto colors can come in a number of genetically distinct patterns, which have different visual characteristics and tend to make white or leave colored different areas of the horse. These include tobiano, sabino, splashed white, frame, and manchado. A pinto horse may also have a combination of these patterns, such as tovero. Pinto patterns can be found in various breeds of horses, notably including the American Paint Horse. Color breed registries such as the Pinto Horse Association of America record pedigree and horse show results for pinto horses, regardless of ancestry. Both the terms "Pinto" and "Paint" may sometimes refer to breeds or registries rather than coat color. Pinto patterns are vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
