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41-549: (Redirected from Greycoat ) Grey coat , Greycoat , Graycoat , or Grey Coat may refer to: Grey (coat colour) of horses Grey Coat School, York , girls' school in York Grey Coat Hospital , girls' school in Westminster, London Greycoats (band) , indie rock group from Minneapolis, Minnesota Confederate States Army soldier, nickname based on: Uniforms of

82-410: A depigmentation pattern. It is a dominant allele , and thus a horse needs only one copy of the gray allele , that is, heterozygous , to be gray in color. A homozygous gray horse, one carrying two gray alleles, will always produce gray foals. Gray is common in many breeds. Today, about one horse in 10 carries the mutation for graying with age. The vast majority of Lipizzaners are gray, as are

123-401: A roan or a rabicano . Some heavily fleabitten grays may also be confused with roans. However, roans are easily distinguishable from grays: roan consists of individual white hairs on a dark base coat, usually with the head and legs of the horse darker than the rest of the body. Rabicanos also have intermixed white hairs primarily on the body with a dark head. With gray horses, the head is often

164-433: A common ancestor that lived at least two thousand years ago. The discovery that gray can be linked to a single animal provides an example of how humans have "cherry-picked" attractive mutations in domestic animals. Gray is controlled by a single dominant allele of a gene that regulates specific kinds of stem cells . Homozygous grays turn white faster, are more likely to develop melanomas, and are less prone to develop

205-439: A gray horse as "white". However, most white horses have pink skin and some have blue eyes. A horse with dark skin and dark eyes under a white hair coat is gray. However, a gray horse with an underlying homozygous cream base coat color may be born with rosy-pink skin, blue eyes and near-white hair. In such cases, DNA testing may clarify the genetics of the horse. Some grays in intermediate stages of graying may be confused with

246-439: A gray horse is homozygous (GG), meaning that it has a gray allele from both parents, it will always produce gray offspring no matter the color genetics of the other parent. However, if a gray horse is heterozygous (Gg), meaning it inherits one copy of the recessive gene (g), that animal may produce offspring who are not gray, depending on the genetics of the other parent and Mendelian inheritance principles . Genetic testing

287-431: A great deal of genetic variation is hidden in the form of alleles that do not produce obvious phenotypic differences. Wild type alleles are often denoted by a superscript plus sign ( i.e. , p for an allele p ). A population or species of organisms typically includes multiple alleles at each locus among various individuals. Allelic variation at a locus is measurable as the number of alleles ( polymorphism ) present, or

328-547: A horse who has papers saying it is "gray" when the horse in front of them appears white. To further complicate matters, the skin and eyes may be other colors if influenced by other factors such as white markings , certain white spotting patterns or dilution genes . The gray gene (G) is an autosomal dominant gene . In simple terms, a horse which has even one copy of the gray allele , regardless of other coat color genes present, will always become gray. This also means that all gray horses must have at least one gray parent. If

369-484: A period of time, others resemble a roan with more uniform intermixing of light and dark hairs. As they age, some gray horses, particularly those heterozygous for the gray gene, may develop pigmented speckles in addition to a white coat, a pattern colloquially called a "fleabitten gray." Gray horses appear in many breeds, though the color is most commonly seen in breeds descended from Arabian ancestors. Some breeds that have large numbers of gray-colored horses include

410-506: A process termed transgenerational epigenetic inheritance . The term epiallele is used to distinguish these heritable marks from traditional alleles, which are defined by nucleotide sequence . A specific class of epiallele, the metastable epialleles , has been discovered in mice and in humans which is characterized by stochastic (probabilistic) establishment of epigenetic state that can be mitotically inherited. The term "idiomorph", from Greek 'morphos' (form) and 'idio' (singular, unique),

451-749: A single-gene trait. Recessive genetic disorders include albinism , cystic fibrosis , galactosemia , phenylketonuria (PKU), and Tay–Sachs disease . Other disorders are also due to recessive alleles, but because the gene locus is located on the X chromosome, so that males have only one copy (that is, they are hemizygous ), they are more frequent in males than in females. Examples include red–green color blindness and fragile X syndrome . Other disorders, such as Huntington's disease , occur when an individual inherits only one dominant allele. While heritable traits are typically studied in terms of genetic alleles, epigenetic marks such as DNA methylation can be inherited at specific genomic regions in certain species,

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492-424: Is Gregor Mendel 's discovery that the white and purple flower colors in pea plants were the result of a single gene with two alleles. Nearly all multicellular organisms have two sets of chromosomes at some point in their biological life cycle ; that is, they are diploid . For a given locus, if the two chromosomes contain the same allele, they, and the organism, are homozygous with respect to that allele. If

533-486: Is a short form of "allelomorph" ("other form", a word coined by British geneticists William Bateson and Edith Rebecca Saunders ) in the 1900s, which was used in the early days of genetics to describe variant forms of a gene detected in different phenotypes and identified to cause the differences between them. It derives from the Greek prefix ἀλληλο-, allelo- , meaning "mutual", "reciprocal", or "each other", which itself

574-545: Is a variant of the sequence of nucleotides at a particular location, or locus , on a DNA molecule. Alleles can differ at a single position through single nucleotide polymorphisms (SNP), but they can also have insertions and deletions of up to several thousand base pairs . Most alleles observed result in little or no change in the function of the gene product it codes for. However, sometimes different alleles can result in different observable phenotypic traits , such as different pigmentation . A notable example of this

615-441: Is how to discern a gray horse from a white horse . White horses usually have pink skin and sometimes even have blue eyes. Young horses with hair coats consisting of a mixture of colored and gray or white hairs are sometimes confused with roan . Some horses that carry dilution genes may also be confused with white or gray. While gray is classified as a coat color by breed registries , genetically it may be more correct to call it

656-477: Is now known that each of the A, B, and O alleles is actually a class of multiple alleles with different DNA sequences that produce proteins with identical properties: more than 70 alleles are known at the ABO locus. Hence an individual with "Type A" blood may be an AO heterozygote, an AA homozygote, or an AA heterozygote with two different "A" alleles.) The frequency of alleles in a diploid population can be used to predict

697-504: Is now possible to determine whether a horse is homozygous or heterozygous for gray. The gray gene does not affect skin or eye color, so grays typically have dark skin and eyes, as opposed to the unpigmented pink skin of white horses . In 2008, researchers at Uppsala University in Sweden identified the genetic mutation that governs the graying process. The study revealed that all gray horses carry an identical mutation that can be traced back to

738-448: Is related to the Greek adjective ἄλλος, allos (cognate with Latin alius ), meaning "other". In many cases, genotypic interactions between the two alleles at a locus can be described as dominant or recessive , according to which of the two homozygous phenotypes the heterozygote most resembles. Where the heterozygote is indistinguishable from one of the homozygotes, the allele expressed

779-439: Is the one that leads to the "dominant" phenotype, and the other allele is said to be "recessive". The degree and pattern of dominance varies among loci. This type of interaction was first formally-described by Gregor Mendel . However, many traits defy this simple categorization and the phenotypes are modelled by co-dominance and polygenic inheritance . The term " wild type " allele is sometimes used to describe an allele that

820-403: Is thought to contribute to the typical phenotypic character as seen in "wild" populations of organisms, such as fruit flies ( Drosophila melanogaster ). Such a "wild type" allele was historically regarded as leading to a dominant (overpowering – always expressed), common, and normal phenotype, in contrast to " mutant " alleles that lead to recessive, rare, and frequently deleterious phenotypes. It

861-798: The Thoroughbred , the Arabian , the American Quarter Horse and the Welsh pony . Breeds with a very high prevalence of gray include the Percheron , the Andalusian , and the Lipizzaner . People who are unfamiliar with horses may refer to gray horses as "white". However, a gray horse whose hair coat is completely "white" will still have black skin (except under markings that were white at birth) and dark eyes. This

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902-431: The pearl gene or "barlink factor", may also create very light-coated horses. Similarly, the champagne gene can lighten coat color, often producing dappling or light colors that can be confused with gray. In spite of its name, the silver dapple gene has nothing to do with graying. It is a dilution gene that acts only on a black coat, diluting the coat to a dark brown and the mane to a flaxen shade. Horses that express

943-412: The "fleabitten" speckling than heterozygous grays. Researchers suggest the pigmented speckles of the "fleabitten" gray, as well as more intense reddish-brown colored areas called "blood" markings, may be caused by a loss or inactivation of the gray allele in some of the somatic cells as that would explain why the speckles are more common on heterozygous grays than homozygotes. The identification of

984-481: The Appaloosa and are seldom seen elsewhere. The dilution genes that create dun, cream, pearl, silver dapple and champagne coloring may occasionally result in confusion with gray. Some horses with a particular type of dun hair coat known as a "blue dun", grullo , or "mouse" dun appear to be a solid gray. However, this color is caused by the dun gene acting on a black base coat, and horses who are dun have all hairs

1025-475: The Confederate States military forces , mostly had gray coats See also [ edit ] " Graycoat Soldiers " track on The Fields of November , 1974 album by Norman Blake Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Grey coat . If an internal link led you here, you may wish to change the link to point directly to

1066-411: The age of a horse except in the broadest of terms: a very young horse will never have a white coat (unless it is a true white horse ), while a horse in its teens usually is completely grayed out. One must also be careful not to confuse the small amount of gray hairs that may appear on some older horses in their late teens or twenties, which do not reflect the gray gene and never cause a complete graying of

1107-561: The age of one year. Over time, white hairs replace the birth color. The changing patterns of white and dark hairs have many informal names, such as "rose gray," "salt and pepper," "iron gray", or "dapple gray." As the horse ages, the coat continues to lighten, often to a pure white. Some horses develop pigmented reddish-brown speckles on an otherwise white hair coat. Such horses are often called "fleabitten gray". Different breeds, and individuals within each breed, take differing amounts of time to gray out. Thus, graying cannot be used to approximate

1148-499: The alleles are different, they, and the organism, are heterozygous with respect to those alleles. Popular definitions of 'allele' typically refer only to different alleles within genes. For example, the ABO blood grouping is controlled by the ABO gene , which has six common alleles (variants). In population genetics , nearly every living human's phenotype for the ABO gene is some combination of just these six alleles. The word "allele"

1189-484: The alternative allele. If the first allele is dominant to the second then the fraction of the population that will show the dominant phenotype is p + 2 pq , and the fraction with the recessive phenotype is q . With three alleles: In the case of multiple alleles at a diploid locus, the number of possible genotypes (G) with a number of alleles (a) is given by the expression: A number of genetic disorders are caused when an individual inherits two recessive alleles for

1230-406: The contrast of the markings of these patterns, sometimes colloquially described as "ghosting." A gray foal may be born any color. However, bay , chestnut , or black base colors are most often seen. As the horse matures, it "grays out" as white hairs begin to replace the base or birth color. Usually white hairs are first seen by the muzzle, eyes and flanks, occasionally at birth, and usually by

1271-476: The first area to lighten, especially around the eyes and muzzle. Also, roans do not lighten with age, while grays always do. The varnish roan is another unusual coloration, sometimes seen in Appaloosa horses, that, like gray, can change with age, but unlike gray, the horse does not become progressively lighter until it is pure white. Varnish roans are created by the action of leopard complex within breeds such as

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1312-403: The frequencies of the corresponding genotypes (see Hardy–Weinberg principle ). For a simple model, with two alleles; where p is the frequency of one allele and q is the frequency of the alternative allele, which necessarily sum to unity. Then, p is the fraction of the population homozygous for the first allele, 2 pq is the fraction of heterozygotes, and q is the fraction homozygous for

1353-467: The gray mutation is of great interest in of medical research since this mutation also enhances the risk for melanoma in horses: some studies have suggested as many as 80% of grays over 15 years of age have some form of melanoma. Growth rate depends on the type, and many are slow-growing, but over time, many develop into a malignant melanoma . The study of gray genetics has pointed to a molecular pathway that may lead to tumour development. Both STX17 and

1394-404: The horse. This change in hair color means that the same gray horse will appear to be a different color over time, sometimes resulting in a need to change the color noted on breed registry papers. Other times, people traveling with gray horses who have a pure white hair coat have encountered problems with non-horse-oriented officials such as police officers or border guards who are unclear about

1435-418: The intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Grey_coat&oldid=1090107637 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Grey (coat colour) The stages of graying vary widely. Some horses develop a dappled pattern for

1476-575: The majority of Andalusian horses . Many breeds of French draft horse such as the Percheron and Boulonnais are often gray as well. Gray is also found among Welsh Ponies , Thoroughbreds , and American Quarter Horses . All of these breeds have common ancestry in the Arabian horse . In particular, all gray Thoroughbreds descend from a horse named Alcock's Arabian , a gray born in 1700. The gray coat color makes up about 3% of Thoroughbreds. Gray also affects spotting patterns of pintos and leopard complex horses such as Appaloosas . Its effects wash out

1517-588: The neighboring NR4A3 gene are overexpressed in melanomas from gray horses, and those carrying a loss-of-function mutation in ASIP (agouti signaling protein) had a higher incidence of melanoma, implying that increased melanocortin-1 receptor signaling promotes melanoma development in Gray horses. Some studies indicate as many as 66% of melanomas become malignant, though other studies have found much lower rates, and in one case, zero. Many people who are unfamiliar with horses refer to

1558-791: The proportion of heterozygotes in the population. A null allele is a gene variant that lacks the gene's normal function because it either is not expressed, or the expressed protein is inactive. For example, at the gene locus for the ABO blood type carbohydrate antigens in humans, classical genetics recognizes three alleles, I , I , and i, which determine compatibility of blood transfusions . Any individual has one of six possible genotypes (I I , I i, I I , I i, I I , and ii) which produce one of four possible phenotypes : "Type A" (produced by I I homozygous and I i heterozygous genotypes), "Type B" (produced by I I homozygous and I i heterozygous genotypes), "Type AB" produced by I I heterozygous genotype, and "Type O" produced by ii homozygous genotype. (It

1599-410: The same color; there is no intermingling of white and dark hairs. Also, dun horses do not get lighter as they age. Horses that are a light cream color are also not grays. These are usually cremello, perlino or smoky cream horses, all colors produced by the action of the cream gene . However, if a gray parent passes on the gene, the hairs will turn white like any other gray. Another cream-colored dilution,

1640-582: The silver dapple gene (and do not have the gray gene) are born that color and it will not lighten. However, again, if one parent passes on the gray gene, the gray gene will again be dominant. Throughout history, both gray and white horses have been mythologized. As part of its legendary dimension, the gray horse in myth has been depicted with seven heads ( Uchaishravas ) or eight feet ( Sleipnir ), sometimes in groups or singly. There are also mythological tales of divinatory gray horses who prophesy or warn of danger. Allele An allele , or allelomorph ,

1681-489: Was formerly thought that most individuals were homozygous for the "wild type" allele at most gene loci, and that any alternative "mutant" allele was found in homozygous form in a small minority of "affected" individuals, often as genetic diseases , and more frequently in heterozygous form in " carriers " for the mutant allele. It is now appreciated that most or all gene loci are highly polymorphic, with multiple alleles, whose frequencies vary from population to population, and that

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