In poultry standards, pungent white is the color of the feathers in chickens ( Gallus gallus domesticus ) characterized by a clean uniform white color in all feathers, which is generally unrelated to depigmentation in other parts of the body.
Color is an important feature of most living organisms. In the wild, color is critical to the survival and success of species reproduction. Environmental constraints that lead to certain colors of birds and animals are very strong and the individuals of the novel color tend not to survive. Under domestication, humans have transformed all the involved species that have been freed from environmental stress for the most part. Early color variants are mostly selected for utility or religious practice reasons. In more recent centuries, color varieties have been created purely for decoration and pleasure, the modes play a huge part in its development. Various colors and confusing patterns can now be found in domestic poultry. In the last decade the color of white fur has become essential for efficient broiler processing and most types of poultry type meat. Slaughterhouses and meat processing plants require poultry with white or very light undercolor to produce carcasses without typical "hair," which are colored by chickens, which require them to burn after picking.
There are some breeds of chicken that have a solid white color like the most distinctive feather colors, such as Leghorn, Dorking, Bresse Gauloise, Polish, Wyandotte and others. And there are many other breeds that are better known for their colored varieties, which also have solid white varieties, such as Plymouth Rock, Orpington, Rhode Island Red, Jersey Giant and others.
Video Solid white (chicken plumage)
Description
Chicks down the color of solid white chicken offspring can vary from creamy white color, through different yellow colors, to grilled orange. In the adult phase, the entire surface of pure white fur is due to the absence of melanin pigmentation in all parts of the hair. The absence of melanin in solid white chicken feathers does not affect other body structures, except in the case of albino, which is easily recognized by the color of red eyes.
Maps Solid white (chicken plumage)
History
Most genetic factors of chicken feathers are manipulated during domestication by selection and crossings, leading to modern breeds of chicken, but no historical record of when or whether the first chicken breeds with dense white fur appeared. In the creation of new white offspring, white color is sometimes introduced from the offspring of dense white fur. Rhode Island White emerged from the work of J. Alonzo Jocoy of Peacedale, Rhode Island, which began in 1888. Developed through the Partridge Cochins cross, White Wyandottes, and White Leghorn rose comb type, compacted during the breed in 1903. And was first received into the Standards of Perfection of the American Poultry Association in 1922. At a time quite popular until the 1960s, it is now a relatively rare bird.
On the other hand, there is no unique genetic mutation for solid white fur color. There are two well-known autosomal main mutations that cause the color of a solid white coat, but also a number of complementary complementary mutations can precisely reduce or limit the pigment with sufficient intensity to produce a final, solid white coat color, even in the absence of mutations for white. Most of the varieties of dense white fur chicken belong to some of the first two primary mutations that cause a solid white fur color. This is generally regarded as "white dominant" and "white recessive" according to the major mutations involved. The term "white dominant" has also been applied in the genetic literature for mutations that produce the color of white feathers on horses.
Four different recessive albino or albino-like mutations that also produce white feathers in chickens are also reported in the literature, but they are not typical of any type of chicken, and may be associated with reduced perinatal ability or vision deficiency.
White dominant
Dominant White is one of the first traits in culture proven to be inherited according to Mendel's law, when in 1902 Bateson discovered that the White Leghorns x Indian Games (or reciprocal) cross gave F1 chicks with white or black and white grayish. And that F2 gives light and dark chicks in 3: 1 Mendel proportions, confirmed by Hurst in 1905, Bateson and Punnet in 1906 and many others. The symbol I (black barrier) to identify this mutation was introduced by Hadley in 1913. Although my homozygous I always has a solid white color , heterozygous I / chicks generally look black, while the presence of black or partially black fur on whitish adult fur is very common.
White recessive
Dorkings of solid white varieties, Plymouth Rocks, Wyandottes, Minorcas, Orpingtons and other breeds are considered as white recessive because their whites are completely recessive to other colors. Both types of white fur: "white dominant" and "white recessive" are phenotypically identical in the adult phase, and can only be distinguished from each other by using progeny test. In 1906 and 1908 Bateson and Punnet showed that White Dorkings is homozygous for autosomal recessive mutations that prevent the appearance of color. They are assigned to this mutation of the c symbol, as recessive from the normal allele ( C , chromogen) which allows the development of normal feather color. This same white fur color was invented by Bateson and Punnet in Rose Comb Bantam and in White Wyandotte. It was also found in White Cochin by Davenport in 1906, in White Langshan by Goodale in 1910, at White Plymouth Rock by Hadley in 1914, and on other offspring.
Chicken "white recessive" may be potentially black prohibited or some other color pattern, but do not reveal this unless they are submitted to the progeny test. The White Plymouth chicken carries a mixture of genes extracted from other breeds that differ from the original Plymouth Rock Barred derived from white varieties.
Albinism and some albinism
Species of dominant white and recessive white fur are not albino, but only white chickens where melanin is limited to the eye. In the ornithological literature there are many reports of albino birds in whole or in part, but most of them are not genetically studied.
In 1933 Warren was portrayed in White Wyandotte as a complete albinism caused by the autosomal recessive mutation he marked as a symbol of a . Like the White Wyandotte birds that have a solid white fur color, albino can only be recognized with bright red eyes. Those albinoians have a vision of such a shortage that the newborn chicks have difficulty finding the feeder, while the adult females find it difficult to find the trap nets provided. They are all very sensitive to sunlight and prefer to stay indoors.
The light microscopic histology of the retinal pigment epithelium of autosomal albinoos was performed in original studies by Warren, but subsequent microscopic light or electron studies of autosomal albino eyes or fur have not been reported. Iris histology shows no evidence of pigmentation. At the ultra-structural level, small, round, and poorly pigmented grains are seen in autosomal albino autosomal retina melanocytes.
In 1940, Warren described an autosomal recessive mutation known as "red eye" ( pk ) that greatly reduced pigmentation in the eye, but only weakened the pigment in the fur, so this mutation did not produce solids. White color. The ultra-melanocyte "red eye" structure of both the eyes and the feathers of chicks and adults has been broadly defined.
In 1941, Mueller and Hutt reported partial sex-related albinism in Barred Plymouth Rock because of the recessive mutations associated with simple sex. The same mutations were later found in other herds of Barred Rocks and White Leghorn. Affected birds have good vision as normal.
In 1983 Brumbaugh, Bargar and Oetting reported the third recessive allele at the pigment locus C , which they gave the symbol c a . This allele on a homozygous individual produces a kind of partial albinism. A concurrent electron microscopy study of both retinal and feather melanocytes showed that both the mutant alleles c and c a were negative cytochemical tyrosinase, had a Golgi hypertrophi system and contains many seemingly incomplete vesicles, non-pigmented granules. Retinal melanocytes have several pigmented granules, more in white recessive cells ( c ) than in albino cells ( c a ). At the ultra-structural level, small, round, and poorly pigmented grains are seen in autosomal albino autosomal retina melanocytes. It describes the eyes little by little but a little dark when a bird is ripe. Both variants are negative cytochemical tyrosinase. Late mortality of the embryo in individuals c a / c a homozigot. Albinos show a shorter lower length, reflecting the general state of immaturity and underdevelopment of neonatal development, higher incidence of subcutaneous bleeding and inflammation, increased incidence of yellow sac bulge and slower growth rates and smaller body size than colored chickens. Mortality in albino is also significantly higher, feed consumption and reduced feed utilization.
The number of changes associated with partial albinism in poultry is difficult to explain merely considering the C locus only the structural genes of tyrosinase. This locus can provide a wider regulatory function. In the opinion of the scientists, there may be additional physiological functions for functional melanin/tyrosinase that are not involved with pigmentation.
Genetics of dense white fur
The legacy of chicken feathers is complex. It depends on several genetic factors that interact in an epistatic manner. The genetic symbology for most of the colored fur mutations can be found in Hutt's genetic classic poultry published in 1949, in Abbott and Yee's Handbook published in 1975 and in the alphabetical list Some genes were published in 1980.
White recessive ( c )
Dense white fur is the result of several combinations of genes that interact to give the final result. Any color expression, except white, requires the presence of a normal allele C , an autosomal dominant allele that allows the synthesis of pigments in feathers. C is the most dominant of the allelic series locus C in the following order of dominance:
C (colored) & gt; c (recessive white) & gt; c a (partial of albinism)
But C is not entirely dominant above c . In 1979 Carefoot found that in certain genetic background homozygous C / C can be distinguished from heterozygotes < C / c
White recessive is one of the two main causes of white fur color. Most of the pure white chicken breeds are purely for the recessive white allele c . c in homozigosity produces solid white fur color on all individuals.
White dominant ( I )
Some offspring such as White Leghorn and Hamburg have "white dominant" mutations for fur color. These mutations selectively inhibit black color and melt the red color on the fur. So, it is also known as the "black barrier". It's less effective in heterozygotes, has a bad effect on red but it reduces black to just a few ticks and spots. In other words, my homozygous / chicken has solid white hair apart from other major or complementary mutations that exist in the individual, but without the effect on melanin eyes. "Dominant white" is also often in breeds that are usually "white recessive", such as White Minorca, White Wyandotte and White Plymouth Rock. Individual Heterozygous / i shows a drastic reduction in black in fur, but only a slight reduction in red pigment. While homozygous people i may have any color if it also carries C alleles that allow normal color expression Due to the ineffectiveness of I to reduce the red pigment, it may escape the attention of the offspring with the color of the fan feather. In 1933, Danforth was able to extract the "dominant white" allele from Buff Leghorns and Buff Minorcas which showed no sign of having this mutation. As in both breeds it is not clear where the "white dominant" mutations are, the results are completely unexpected until revelation by a progeny test. The "white dominant" presence of the White Leghorn is due to previous crossings made with the intention of introducing some of the desired qualities of this breed. Disadvantages associated with white recess
Since 1959 it has been reported that the recessive white allele c in homocygosis significantly reduces body growth rate and body size in magnitude 4-10%. This is then confirmed in chicken types by Fox and Smyth research, and in eggs by research MÃÆ'¨rat and co-workers. This is a serious loss to the production of poultry meat that is still unsolved to date. White or very light undercolor colors are essential for the processing of broilers and efficient dilapidated layers in slaughterhouses and meat processing plants, but White Plymouth Rock, a typical "white recessive" type, continues to be used as the female side of most commercial broilers. , while White Cornish continues to be used as a male side. As a result, most modern broiler chickens are homozygous c / c . It is important for the meat breeding industry to know the magnitude of depression in the growth rates caused by recessive white genotypes in commercial stock. In addition, several other pigment dilution genes have been reported to suppress growth rates. The results of the Fox and Smyth experiments in 1985 also proved that white and white (white recessive) and I did not act additively to influence the rate of growth, and more. Importantly, the depression observed for "white recessive" is not enhanced by the presence of "white dominant" ( I ). As part of the future strategy of genetic work on the parent stock of the male side. There is no need to eliminate the "white dominant" separation from the recessive white line, but it will be economically advantageous to remove the "white recessive" from men. line.
Breeds white chicken with "white dominant"
- Brahma, white, [1] common and bantam
- Hamburg white (rare breeds) [2]
- La Bresse
- White leghorn; regular single-comb, single-comb bantam, and regular rose-comb
- Minorca, white; single- [3] and rose-comb
- Modern, white, regular [4] and bantam games
- Polish white color; regular and bantam; bearded and beardless [5] in both sizes
- Rhode Island White, normal [6] and comb-rose
Breed white chicken with "white recess"
- Araucana, white [7]
- Acyl, white [8]
- Australia Langshan (little known outside Australia) [9]
- Australorp, white, common [10] and bantam
- Barnevelder, white, big/bantam [11] (source in German)
- Bearded d'Uccle bantam, white
- Belgian Bearded d'Anvers bantam, white
- Catalana del Prat, Spain: blanca ('white') [12], [13]
- White is clean, orderly [14] and bantam
- Cochin white, regular [15] and frizzle
- Langshan, white [16]
- Cubalaya, white [17]
- Dorking, white, rose comb [18]
- Faverolles, white, regular [19] and bantam
- Sunbathing, white, regular, and bantam (this term can also describe this type of bird feather and this special type)
- Langshan German
- White Bantam Japan
- Giant white Jersey [20]
- Lamona (almost extinct) [21]
- Langshan bantam, white [22]
- Malay bantam, white
- Old English, white, regular, and bantam games
- Orpington, white, regular [23] and bantam
- Plymouth Rock, white; regular [24], bantam, and dwarf
- Silkie, white, beardless or bearded (white recessive); and bantam, white, not bearded
- Sultan (chicken) white
- Transylvanian Naked-neck, white [25], regular and bantam
- Wyandotte, white, [26] regular and bantam
- Yokohama, white [27]
Solid white fur on other species
The occurrence of dense white fur is widespread among bird species. This type of phenotype mostly results from a single mutation associated with the absence of melanin deposition.
Turkey Turkey ( Meleagris gallopavo )
The original wild bristle color of turkey ( Meleagris gallopavo ) is bronze, but the color of white fur is solid because of the autosomal allele recessive ( c ) in homocygosis is the most frequent phenotype, extended by domestication and imposed by the requirements of the meat processing factory.
Hutt and Mueller (1942) found partial albinism in bronze turkeys determined by simple, semi-lethal sex-linked genes during the incubation period or thereafter. The blindness associated with albinism limits the individual to finding water and food. Incomplete sex-related albinism in turkey is different from chicken. Mutations in turkeys eliminate melanin from the retina, causing blindness and causing death for most individuals.
Japanese pheasant ( Coturnix japonica )
There are various white quail whales ( Coturnix japonica ) with black eyes. Dense white fur is due to an autosomal recessive allele ( wh ) in homocygosis, although some birds may exhibit some black spots. This mutant color gene produces a white quail with dark eyes when homozygous and a two-color pattern known as "tuxedo" when heterozygous. The white tuxedo pattern on the ventral surface, including the neck and face, while the dorsal surface is a blending of black and brown pigments.
There are also other mutations ( W ) that are autosomal dominant incomplete. Homozygous for mutant coat has white fur, while the heterozygote for the gene shows the color of the dissolved fur. But homozygous quail for this gene has low viability.
It has also described an imperfect sex-related albinism due to the recessive allele al . This mutant pigmentation produces an abnormal level of eye pigmentation and affected quail feathers. The faint lines on the backs of adults seem to be due to structural colors only. Perinatal survival is reduced in the homozygous quar for this gene.
Wild canary ( Serinus canaria )
There is semi-albinism in wild canary ( Serinus canaria , Fringillidae ) that produces pink eye when hatching. The eyes become dark in the adult phase and the fur is not pure white but is described as cinnamon. This is due to genes associated with sex and is the first experimental demonstration of a sex-related heritage in birds after the rediscovery of Mendel's law.
An autosomal dominant white has also been described in the lethal wild walnut in homozygous. All the studied individuals happened to be heterozygous, giving offspring white and colored birds in proportion to 2: 1. Homozygous dead in the early phase of embryonic development.
Other bird species
KokemÃÆ'¼ller (1935) describes the albinism associated with sex in budgerigar ( Melopsittacus undulatus , Psittacidae ). This type of albinism eliminates the melanin and structural colors found in the carrier genes, leaving untouched lipokrom pigments. As a result, budgerigars, which would otherwise become green with some black dots, become brilliant yellow with pink eyes.
Cook (1939) describes albinism descendants in American robin ( Turdus migratorius L., Turdidae ).
McIlhenny (1940) found a type of albinism in the northern mockingbird ( Mimus polyglottos L., Mimidae ) that was inherited as a simple autosomal recessive.
See also
- Lavender (chicken feather)
- Dark black (chicken feathers)
- List of chickens
- Chicken color list
References
Source of the article : Wikipedia
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