The Siamese cat is one of the first distinctly recognized breeds of Asian cat. Derived from the Wichianmat landrace, one of several varieties of cat native to Thailand (formerly known as Siam), the Siamese became one of the most popular breeds in Europe and North America in the 19th century. The carefully refined modern Siamese is characterized by blue almond-shaped eyes; a triangular head shape; large ears; an elongated, slender, and muscular body; and point colouration. (Aside from the colouration, it bears little resemblance to the original stock, and the more moderate, traditional or "old-style" Siamese, with a much rounder head and body, has been re-established by multiple registries as the Thai cat.) The International Cat Association describes the modern Siamese as affectionate, social, intelligent, and playful into adulthood, often enjoying a game of fetch.^[1] Siamese tend to seek human interaction and also like companionship from other cats.

The Siamese (sometimes in the traditional form) is among the foundation stock of several other breeds developed by crossbreeding with other cats; some examples are the Oriental Shorthair and Colourpoint Shorthair, developed to expand the range of coat patterns; the long-haired variant most often dubbed the Himalayan; and hair-mutation breeds including the Cornish Rex, Sphynx, Peterbald, and the blue point Siamese cat. The Siamese cat comes in two distinct variations: traditional, with an apple-shaped head and a slightly chubby body; or the modern Siamese, which are very skinny and have a wedge-shaped head.

 

Origins

Thailand

A description and depiction of the Wichienmaat (Siamese cat) first appears in a collection of ancient manuscripts called the Tamra Maew (The Cat-Book Poems) thought to originate from the Ayutthaya Kingdom (1351 to 1767 AD). Over a dozen are now kept in the National Library of Thailand, while others have resurfaced outside of Thailand and are now in the British Library and National Library of Australia. In addition to the old Siamese cat, the Tamra Maew also describes other heritage cats of Thailand including the Korat cat (Malet) which are still bred for preservation in Thailand today and have become popular in other countries, and Konja cat (Black cat), Suphalak (a controversy in Burmese cat).
When the capital city Ayutthaya was sacked on 7 April 1767 at the end of the Burmese-Siamese war the Burmese army burned everything in sight and returned to Burma taking Siamese noblemen and royal family members with them as captives. Buddha images were hacked apart for their gold, and all the royal treasures were stolen. Thai legend has it that the Burmese King Hsinbyushin found and read the poem for the Thai cats in the Tamra Maew. The poem describes the all Thai cats as being as rare as gold, and anyone that owns this cat will become wealthy. He told his army to round up all the Suphalak cats and bring them back to Burma along with the other treasures. Today in Thailand this legend is told as a humorous explanation as to why the all Thai cats are so rare.
The pointed cat known in the West as "Siamese", recognized for its distinctive markings, is one of several breeds of cats from Siam described and illustrated in manuscripts called "Tamra Maew" (Cat Poems), estimated to have been written from the 14th to the 18th century.^[2] In 1878, U.S. President Rutherford B. Hayes received the first documented Siamese to reach the United States, a cat named "Siam" sent by the American Consul in Bangkok.^[3] In 1884, the British Consul-General in Bangkok, Edward Blencowe Gould (1847–1916),^[4] brought a breeding pair of the cats, Pho and Mia, back to Britain as a gift for his sister, Lilian Jane Gould (who, married in 1895 as Lilian Jane Veley,^[5] went on to co-found the Siamese Cat Club in 1901). In 1885, Gould's UK cats Pho and Mia produced three Siamese kittens—Duen Ngai, Kalohom, and Khromata—who were shown with their parents that same year at London's Crystal Palace Show. Their unique appearance and distinct behaviour attracted attention but all three of the kittens died soon after the show, their cause of death not documented.^[6]
By 1886, another pair (with kittens) was imported to the UK by Eva Forestier Walker (surnamed Vyvyan after 1887 marriage)^[7] and her sister, Ada. Compared to the British Shorthair and Persian cats that were familiar to most Britons, these Siamese imports were longer and less "cobby" in body types, had heads that were less rounded with wedge-shaped muzzles and had larger ears. These differences and the pointed coat pattern, which had not been seen before in cats by Westerners, produced a strong impression—one early viewer described them as "an unnatural nightmare of a cat." Over the next several years, fanciers imported a small number of cats, which together formed the base breeding pool for the entire breed in Britain. It is believed that most Siamese in Britain today are descended from about eleven of these original imports. In their early days in Britain, they were called the "Royal Cat of Siam", reflecting reports that they had previously been kept only by Siamese royalty.^[8] Later research has not shown evidence of any organised royal breeding programme in Siam.^[2] The original Siamese imports were medium-sized, rather long-bodied, muscular, graceful cats with moderately wedge-shaped heads and ears that were comparatively large but in proportion to the size of the head. The cats ranged from substantial to slender but were not extreme in either way.
The breed standard of the modern Siamese calls for an elongated, tubular, and muscular body and a triangular head, forming a perfect triangle from the tip of the nose to each tip of the ear. The eyes are almond-shaped and light blue, while the ears are large, wide-based, and positioned more towards the side of the head. The breed has a long neck, a slender tail, and fur that is short, glossy, fine, and adheres to the body with no undercoat. Its pointed color scheme and blue eyes distinguish it from the closely related Oriental Shorthair. The modern Siamese shares the pointed color pattern with the Thai, or traditional Siamese, but they differ in head and body type.
The pointed pattern is a form of partial albinism, resulting from a mutation in tyrosinase, an enzyme involved in melanin production. The mutated tyrosinase enzyme is heat-sensitive; it fails to work at normal body temperatures, but becomes active in cooler (< 33 °C) areas of the skin.^[12] This results in dark colouration in the coolest parts of the cat's body, including the extremities and the face, which is cooled by the passage of air through the sinuses. All Siamese kittens, although pure cream or white at birth, develop visible points in the first few months of life in colder parts of their body.^[13] By the time a kitten is four weeks old, the points should be sufficiently clearly distinguishable to recognise which colour they are. Siamese cats tend to darken with age, and generally, adult Siamese living in warm climates have lighter coats than those in cool climates. Originally the vast majority of Siamese had seal (extremely dark brown, almost black) points, but occasionally Siamese were born with "blue" (a cool grey) points, genetically a dilution of seal point; chocolate (lighter brown) points, a genetic variation of seal point; or lilac (pale warm gray) points, genetically a diluted chocolate. These colours were at first considered "inferior" seal points, and were not qualified for showing or breeding. All of these shades were eventually accepted by the breed associations, and became more common through breeding programmes specifically aimed at producing these colours. Later, outcrosses with other breeds developed Siamese-mix cats with points in other cat colours and patterns, including Red and Cream point, lynx (tabby) point, and tortoise-shell ("tortie") point. (For more information on cat coat terminology, see Cat coat genetics.)
In the United Kingdom, all pointed Siamese-style cats are considered part of the Siamese breed. In the United States, a major cat registry, the Cat Fanciers' Association, considers only the four original fur colors as Siamese: seal point, blue point, chocolate point, and lilac point. Oriental Shorthair cats with color points in colors or patterns aside from these four are considered color point Short hairs in that registry. The World Cat Federation has also adopted this classification, treating the color point Short hair as a distinct breed.^[10]
Many Siamese cats from Thailand had a kink in their tails, but over the years this trait has been considered a flaw. Breeders have largely eradicated it, but the kinked tail persists among street cats in Thailand. 

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0 فبراير 01, 2019

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The British Shorthair is the pedigreed version of the traditional British domestic cat, with a distinctively chunky body, dense coat and broad face. The most familiar color variant is the "British Blue", a solid blue-gray with copper eyes, medium tail, but the breed has also been developed in a wide range of other colours and patterns, including tabby and colorpoint.

It is one of the most ancient cat breeds known, probably originating from European domestic cats imported into Britain by the invading Romans in the first century AD. In modern times, it remains the most popular pedigreed breed in its native country, as registered by the UK's Governing Council of the Cat Fancy (GCCF).

The breed's good-natured appearance and relatively calm temperament make it a frequent media star, notably as the inspiration for John Tenniel's famous illustration of the Cheshire Cat from Alice in Wonderland. The Cat Fanciers' Association profile reads: "When gracelessness is observed, the British Shorthair is duly embarrassed, quickly recovering with a 'Cheshire cat smile'”.^[1]

Contents

• 1 History
• 2 Description
  • 2.1 Appearance
  • 2.2 Coat, colour and patterns
  • 2.3 Temperament
• 3 Health
• 4 In popular culture
• 5 References
• 6 External links

History

The origins of the British Shorthair most likely date back to the first century AD, making it one of the most ancient identifiable cat breeds in the world.^{[citation needed]} It is thought that the invading Romans initially brought Egyptian domestic cats to Great Britain; these cats then interbred with the local European wildcat population. Over the centuries, their naturally isolated descendants developed into distinctively large, robust cats with a short but very thick coat, the better to withstand conditions on their native islands. Based on artists' representations, the modern British Shorthair is basically unchanged from this initial type.^[2]

An early example of the "English type" Blue Shorthair, from Frances Simpson's Book of the Cat, 1903

Selective breeding of the best examples of the type began in the nineteenth century, with emphasis on developing the unusual blue-grey variant called the "British Blue" or "English type" (to distinguish it from the more fine-boned "Russian type") in particular. Some sources directly credit UK artist and pioneering cat fancier Harrison Weir with the initial concept of standardizing the breed; others suggest a group of breeders may have been involved. The new British Shorthair was featured at the first-ever cat show, organised by Weir and held at the Crystal Palace in London in 1871, and enjoyed great initial popularity.^[3]

By the 1890s, however, with the advent of the newly imported Persian and other long-haired breeds, the British Shorthair had fallen out of favour, and breeding stock had become critically rare by World War I.^{[citation needed]} At least partially to alleviate this, British Shorthair breeders mixed Persians into their bloodlines.^{[citation needed]} The genes thus introduced would eventually become the basis for the British Longhair; at the time, however, any long-haired cats produced were placed into the Persian breeding program.^{[citation needed]} As all cats with the "blue" colouration were then judged together as variants on a de facto single breed, the Blue Shorthair, outcrossings of the British with the Russian Blue were also common.^[2]

A young British Blue male showing the copper eyes typical of cats with 'blue' fur.

After the war, in an attempt to maintain the breed standard, the GCCF decided to accept only third-generation Persian/British Shorthair crosses.^{[citation needed]} This contributed to another shortage of pure breeding stock by World War II, at which point the Persian and Russian Blue were reintroduced into the mix.^{[citation needed]} British Shorthair breeders also worked with the French Chartreux, another ancient breed, which although genetically unrelated to the British Blue is a very similar cat in appearance. After the war, breeders worked to re-establish the true British type, and by the late 1970s the distinctive British Shorthair had achieved formal recognition from both the American a (CFA) and The International Cat Association (TICA).^[2] According to the GCCF's 2013 registry data, it is once again the most popular pedigreed breed in its native country.^[4]

Description

Appearance

A fully mature British Blue male, showing the characteristic heavy jowls and unique "crisp" texture of the coat

The British Shorthair is a relatively powerful-looking large cat, having a broad chest, strong thick-set legs with rounded paws and a medium-length, blunt-tipped tail. The head is relatively large and rounded, with a short muzzle, broad cheeks (most noticeable in mature males, who tend to develop prominent jowls) and large round eyes that are deep coppery orange in the British Blue and otherwise vary in colour depending on the coat. Their large ears are broad and widely set.^[5]

The 'British Blue' variant can often be confused with the grey Scottish Fold. However, the Shorthair can be characterised by having its pointy triangle ears, whereas the Fold has softer, folded ears.

They are slow to mature in comparison with most cat breeds, reaching full physical development at approximately three years of age. Unusually among domestic cats they are a noticeably sexually dimorphic breed, with males averaging 9–17 lb (4.1–7.7 kg) and females 7–12 lb (3.2–5.4 kg).^[6][7]

Coat, colour and patterns

The British Shorthair's coat is one of the breed's defining features. It is very dense but does not have an undercoat; thus, the texture is plush rather than woolly or fluffy, with a firm, "crisp" pile that breaks noticeably over the cat's body as it moves.^[2][5]

Although the British Blue remains the most familiar variant, British Shorthairs have been developed in many other colours and patterns. Black, blue, white, red, cream, silver, golden and—most recently—cinnamon and fawn are accepted by all official standards, either solid or in colourpoint, tabby, shaded and bicolour patterns; the GCCF, FIFe and TICA also accept chocolate and its dilute lilac, disallowed in the CFA standard.^[8] All colours and patterns also have tortoiseshell variants.^[5]

The Tabby patterns include:^[9] Classic Tabby, Mackerel Tabby, Spotted & Ticked Tabby. The non-tabby patterns include: Tortoiseshell, Bi-Colour, Van patterns Bi-Colour & White, Smoke, Tipped & Colourpointed.

• 

  4-month-old golden shaded male kitten
  
• 

  5-month-old lilac female kitten
  
• 

  Blue bicolour adult male
  
• 

  6-month-old silver classic tabby male kitten
  

• 

  Fawn and white bicolour adult male
  
• 

  Seal point with white adult female
  
• 

  Dilute blue-cream calico adult female
  

Temperament

They are an easygoing and dignified breed, not as active and playful as many but sweet-natured and devoted to their owners, making them a favourite of animal trainers. They tend to be safe around other pets and children since they will tolerate a fair amount of physical interaction, but as a rule do not like to be picked up or carried. They require only minimal grooming and take well to being kept as indoor-only cats; however, they can be prone to obesity unless care is taken with their diet.^[2][6]

Health

The UK breed committee considers the British Shorthair a long-lived cat, with a life expectancy of 14–20 years.^[10] Vet clinic data from England shows a median lifespan of 11.8 years.^[11] Swedish insurance data puts the median lifespan of the breed at >12.5 years. 82% of British Shorthairs lived to 10 years or more and 54% lived to 12.5 years or more.^[12]

Hypertrophic cardiomyopathy (HCM) can be a problem in the breed. A Danish prevalence study with more than 329 cats showed that 20.4% of males and 2.1% of the females had HCM. On top of this 6.4% of males and 3.5% of females were judged to be equivocal.^[13][13] HCM testing of males used for breeding is now mandatory for breeders organized under the Danish Fife member, Felis Danica.^[14]

The breed is thought to be at high risk of polycystic kidney disease (PKD).^[15] A DNA test lab has noted a significant decrease of the PKD mutations in tested populations. Carrier frequency is now at 1%.^[16]

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0 يناير 27, 2019

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Calico cat

Calico cats are domestic cats with a spotted or particolored coat that is predominantly white, with patches of two other colors (often orange and black, sometimes gray). Outside North America, the pattern is more usually called tortoiseshell and white. In the province of Quebec, Canada, they are sometimes called chatte d'Espagne (French for '(female) cat of Spain'). Other names include brindle, tricolor cat, tobi mi-ke (Japanese for 'triple fur'), and lapjeskat (Dutch for 'patches cat'); calicoes with diluted coloration have been called calimanco or clouded tiger. Occasionally, the tri-color calico coloration is combined with a tabby patterning; this calico-patched tabby is called a caliby.^[1]

"Calico" refers only to a color pattern on the fur, not to a breed or two-colored eyes on a cat.^[2] Among the breeds whose standards allow calico coloration are the Manx, American Shorthair, British Shorthair, Persian, Arabian Mau, Japanese Bobtail, Exotic Shorthair, Siberian, Turkish Van, Turkish Angora and Norwegian Forest Cat.

Because genetic determination of coat colors in calico cats is linked to the X chromosome, calicos are nearly always female, with one color linked to the maternal X chromosome and a second color linked to the paternal X chromosome.^[2][3] Because males only have one X chromosome, they can be orange or black, but a male calico would have to have a rare condition where they have three sex chromosomes (two X chromosomes and one Y chromosome) in order to be calico. In addition to other symptoms caused by the condition, these male calicos are often sterile.

There is also a type of calico cat referred to as a dilute calico. Dilute calicos are not necessarily rare. They are recognized by their grey, silver, and gold colors instead of the traditional white, black, brown or red patched coat of a calico. Dilute calicos are also called light calicos, because they usually have no dark-colored fur

 

.

History

The coat pattern of calico cats does not define any breed, but occurs incidentally in cats that express a range of color patterns; accordingly the effect has no definitive historical background. However, the existence of patches in calico cats was traced to a certain degree by Neil Todd in a study determining the migration of domesticated cats along trade routes in Europe and Northern Africa.^[4] The proportion of cats having the orange mutant gene found in calicoes was traced to the port cities along the Mediterranean in Greece, France, Spain and Italy, originating from Egypt.^[5]

Genetics

Main article: Tortoiseshell cat

Two calico cats from the same litter with different markings.

In genetic terms, calico cats are tortoiseshells in every way, except that in addition they express a white spotting gene. There is however one anomaly: as a rule of thumb the larger the areas of white, the fewer and larger the patches of ginger and dark or tabby coat.^{[citation needed]} In contrast a non-white-spotted tortoiseshell usually has small patches of color or even something like a salt-and-pepper sprinkling. This reflects the genetic effects on relative speeds of migration of melanocytes and X-inactivation in the embryo.^[6]

Serious study of calico cats seems to have begun about 1948 when Murray Barr and his graduate student E.G. Bertram noticed dark, drumstick-shaped masses inside the nuclei of nerve cells of female cats, but not in male cats. These dark masses became known as Barr bodies.^[7] In 1959, Japanese cell biologist Susumu Ohno determined the Barr bodies were X chromosomes.^[7] In 1961, Mary Lyon proposed the concept of X-inactivation: one of the two X chromosomes inside a female mammal shuts off.^[7] She observed this in the coat color patterns in mice.^[8]

Calico cats are almost always female because the locus of the gene for the orange/non-orange coloring is on the X chromosome. In the absence of other influences, such as color inhibition that causes white fur, the alleles present in those orange loci determine whether the fur is orange or not. Female cats, like all female placental mammals, normally have two X chromosomes. In contrast, male placental mammals, including chromosomally stable male cats, have one X and one Y chromosome.^[2][7][9] Since the Y chromosome does not have any locus for the orange gene, there is no chance that an XY male could have both orange and non-orange genes together, which is what it takes to create tortoiseshell or calico coloring.^{[citation needed]}

One exception is that in rare cases faulty cell division may leave an extra X chromosome in one of the gametes that produced the male cat. That extra X then is reproduced in each of his cells, a condition referred to as XXY, or Klinefelter syndrome. Such a combination of chromosomes could produce tortoiseshell or calico markings in the male, in the same way as XX chromosomes produce them in the female.^{[citation needed]}

All but about one in three thousand of the rare calico or tortoiseshell male cats are sterile because of the chromosome abnormality, and breeders reject any exceptions for stud purposes because they generally are of poor physical quality and fertility. In any event, because the genetic conditions for calico coloring are X linked, a fertile male calico's coloring would not have any determination in the coloring of any male offspring (who would receive the Y, not the X chromosome from their father).

As Sue Hubble stated in her book Shrinking the Cat: Genetic Engineering before We Knew about Genes,

The mutation that gives male cats a ginger-colored coat and females ginger, tortoiseshell, or calico coats produced a particularly telling map. The orange mutant gene is found only on the X, or female, chromosome. As with humans, female cats have paired sex chromosomes, XX, and male cats have XY sex chromosomes. The female cat, therefore, can have the orange mutant gene on one X chromosome and the gene for a black coat on the other. The piebald gene is on a different chromosome. If expressed, this gene codes for white, or no color, and is dominant over the alleles that code for a certain color (i.e. orange or black), making the white spots on calico cats. If that is the case, those several genes will be expressed in a blotchy coat of the tortoiseshell or calico kind. But the male, with his single X chromosome, has only one of that particular coat-color gene: he can be not-ginger or he can be ginger (although some modifier genes can add a bit of white here and there), but unless he has a chromosomal abnormality he cannot be a calico cat.^[5]

It is currently impossible to reproduce the fur patterns of calico cats by cloning. Penelope Tsernoglou wrote "This is due to an effect called x-linked inactivation which involves the random inactivation of one of the X chromosomes. Since all female mammals have two X chromosomes, one might wonder if this phenomenon could have a more widespread impact on cloning in the future."^[10]

Calico cats may have already provided findings relating to physiological differences between male and female mammals.^[7][9][11]

Folklore

Cats of this coloration are believed to bring good luck in the folklore of many cultures.^[12] In the United States, these are sometimes referred to as money cats.^[13] A cat of the calico coloration is also the state cat of Maryland in the United States.^[14] In the late nineteenth century, Eugene Field published "The Duel", a beloved poem for children also known as "The Gingham Dog and the Calico Cat". In Japan, the Maneki-neko figures depict calico cats, bringing good luck; and Japanese sailors often had a calico ship's cat to protect against misfortune at sea.^[15]

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0 يناير 27, 2019

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Snowshoe Cat

hi every one today we will talk about this sweet kind of cats they say its have beautiful name call : snowshoe cats

The Snowshoe is a breed of cat originating in the United States of America in the 1960s. Snowshoes were first produced in Philadelphia when a Siamese breeder's cat gave birth to three kittens with white feet. The breeder, Dorothy Hinds-Daugherty, then began a breeding program to produce what were originally called "Silver Laces",^[1] crossing the strangely marked Siamese cats with bi-color American Shorthair cats and other breeds. When Hinds-Daugherty left the program, Vikki Olander began working with the cats and recruited new breeders, as well as worked towards full recognition within cat associations. Despite having existed for 45 years, Snowshoes are rare due to the difficulty of reproducing the correct coat markings. The marks are based on recessive genes for color points and on the co-dominant but variably-expressed piebald pattern gene, making it difficult to predict the appearance of offspring.

The coat coloration recognized by registries and associations is point coloration, and it comes in a variety of colors, though some organizations do not recognize certain colors. Snowshoe cats have an affectionate and docile disposition. Due to this, they do not do well under circumstances where they are left alone for long periods of time. Snowshoes are also very vocal, though their voices are not as loud as the Siamese, a cat found in their breed heritage. They are noted as being very intelligent and have the ability to learn tricks and open doors. These cats also enjoy water, and may swim

..

Personality

Snowshoes are generally affectionate, sweet-tempered, and mellow.^[2][3] They enjoy the company of humans and being given attention, and are compatible with children and other pets.^[2] Snowshoes are very social and docile, and show great devotion and love towards their owners. Consequently, the breed dislike being left alone for long periods of time and are able to cope with working hours better if they have another cat companion.^[3] Snowshoes may express themselves and their complaints vocally, though their meows are not as loud as the Siamese. It is not unusual for a snowshoe to look concerned, they generally have a worried or concerned expression on their face for the majority of the time. ^[2][3] The cats are also noted as being intelligent; they can learn to open various types of doors, and can be taught tricks, especially fetch.^[3] Snowshoes also enjoy water, particularly running water, and may on occasion swim.^[2][3] Though very active, they are not restless or easily agitated, and they have a fondness for perching in high places.^[3]

 

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0 يناير 22, 2019

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Polydactyl Cat

hi today we will talk about this type of cats they call them Poplydactyl Cat 

A polydactyl cat is a cat with a congenital physical anomaly called polydactyly (or polydactylism, also known as hyperdactyly), which causes the cat to be born with more than the usual number of toes on one or more of its paws. Cats with this genetically inherited trait are most commonly found along the East Coast of North America (in the United States and Canada) and in South West England and Wales

 

True polydactyly is a congenital abnormality, genetically inherited as an autosomal dominant trait of the ZRS cis element of the Pd gene with incomplete penetrance.^[1]

Normal cats have a total of 18 toes, with five toes on each fore paw, and four toes on each hind paw; polydactyl cats may have as many as eight digits on their front and/or hind paws. Both Jake, a Canadian polydactyl cat, and Paws, an American polydactyl cat, were recognised by Guinness World Records as having the highest number of toes on a cat, 28.^[2] Various combinations of anywhere from four to seven toes per paw are common.^[3] Polydactyly is most commonly found on the front paws only, it is rare for a cat to have polydactyl hind paws only, and polydactyly of all four paws is even less common.

Feline radial hypoplasia (see squitten) is a mimic of polydactyly and is considered a severe condition. Radial hypoplasia may cause the formation of extra jointed toes, but it is not a result of the gene normally associated with polydactyls. It thus does not cause the "mitten cat" or "thumb cat" condition where the extra toes occur separated from the normal ones just like a dewclaw, usually associated with an additional pad which makes them look like an underdeveloped foot sticking out near the base of the normal toes. Rather, radial hypoplasia-related extra toes are immediately adjacent to the normal ones, giving the cat overly large, flat feet — colloquially known as "patty feet" or "hamburger feet". Though this looks less serious than true polydactyly (as the feet appear "normal" apart from having one or two extra toes), breeding such cats will eventually result in severely disabled offspring.[

 

History and folklore

 

The condition seems to be most commonly found in cats along the East Coast of North America (in the United States and Canada)^[4] and in South West England, Wales and Kingston-upon-Hull.^{[citation needed]} Polydactyl cats have been extremely popular as ship's cats.^[4] Although there is some controversy over whether the most common variant of the trait originated as a mutation in New England or was brought there from Britain, there seems to be agreement that it spread widely as a result of cats carried on ships originating in Boston, Massachusetts, and the prevalence of polydactyly among the cat population of various ports correlates with the dates when they first established trade with Boston.^[4] Contributing to the spread of polydactyl cats by this means, sailors were long known to value polydactyl cats especially for their extraordinary climbing and hunting abilities as an aid in controlling shipboard rodents.^[4] Some sailors thought they bring good luck at sea.^[4] The rarity of polydactyl cats in Europe may be because they were hunted and killed due to superstitions about witchcraft.^[4]

Genetic work studying the DNA basis of the condition indicates that many different mutations can all lead to polydactyly.^[1]

Nobel Prize-winning author Ernest Hemingway was a famous aficionado of polydactyl cats, after being first given, by a ship captain, a six-toed cat he named Snow White.^[5][6][7] Upon Hemingway's death in 1961, his former home in Key West, Florida became a museum and a home for his cats, and it currently houses approximately fifty descendants of his cats (about half of which are polydactyl).^[7] Because of his love for these animals, polydactyl cats are sometimes referred to as "Hemingway cats".^[7][8]

 

Genetics

In the case of preaxial polydactyly of the Maine Coon cat (Hemingway mutant) a mutation of the cis-regulatory element ZRS (ZPA regulator sequence) is associated. ZRS is a noncoding element, 800.000 basepairs remote to the target gene Shh. An ectopic expression of Shh is seen on the anterior side of the limb. Normally Shh is expressed in an organiser region, called the zone of polarizing activity (ZPA) on the posterior limb side. From there it diffuses anteriorly, laterally to the growth direction of the limb. In the mutant mirroring smaller ectopic expression in a new organiser region is seen on the posterior side of the limb. This ectopic expression causes cell proliferation delivering the raw material for one or more new digits.^[11][1][12]

Polydactyly is a spontaneous complex phenotypic variation, developed in one generation. In the concrete preaxial form of the Hemingway mutant the variation is induced by a single point mutation in a noncoding cis-regulatory element for Shh. In an extensive phenotypic variation like this, one or more complete digits at each single limb are developed including nerves, blood vessels, muscles and ligaments. The physiology of the digits can be perfect. This complex phenotypic result cannot be explained by the mutation alone. The mutation can only induce the variation. In the consequence of the mutation thousands of events, each different from the wildtype, occur on different organisation layers, i.e. expression changes of other genes, cell-cell signal exchange, cell differentiation, cell and tissue growth. The summarized small random changes on all layers build the raw material and the process steps for the generation of the plastic variation.^[3] The mentioned form of polydactyly of the Hemingway mutant shows a biased variation. In a recent empirical study first the number of extra toes of 375 mutant Maine Coon cats were variable (polyphenism) and second, the number of extra toes followed a discontinuous statistical distribution. They were not equally distributed as one might expect of an identical single point mutation. The example demonstrates that the variation is not explained completely by the mutation alone.^[3]

 

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0 يناير 22, 2019

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The 10 Best Types of Cat

Hello Every one 

 

hi today we should compile a list of "best cats”—this is the internet, after all. Two intrepid and cat-crazy editors have finally taken on this task for your enjoyment. After much considered debate, we present you a definitive list of best cats, according to us.

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• Polydactyl

  

  © ckellyphoto/Fotolia

  Let’s be real, polydactyl cats give the best high-fives. Errr, high-sixes. Also known as "mitten cats" or "thumb cats," polydactyls have a genetic mutation that gives them more than the usual number of toes on one or more feet. Polydactyl cats can have anywhere from six to eight toes per paw. The extra toes sometimes make them look like their paws have thumbs. While polydactyly can happen in many different animals (including humans), it’s arguably cutest in cats. Writer Ernest Hemingway certainly thought so—he himself was a polydactyl owner, and the Ernest Hemingway Home and Museum is now home to some 50 polydactyl cats.

• Snowshoe

  

  © Jan S. /Shutterstock.com

  With its white muzzle and feet, dark "points," and blue eyes, the Snowshoe looks like what it was bred from: a Siamese with white "boots" that turned up in the litter of a Siamese breeder in Philadelphia in the 1960s. The particular Snowshoe look is difficult to breed, so registered purebred Snowshoe cats are rare. But there are many cats in shelters who have some or all of its traits, such as the white paws, dark mask, and beautiful blue eyes—so if you’re interested in this kind of cat, you can always get "the look for less."

• Calico

  

  Alison Eldridge

  It is impossible to clone a calico cat with the same markings, because of the random activation of genes. The necessary traits for calico patterning are on the X-chromosome, therefore nearly all calico cats are female. Male calico cats are few and far between, and can only exist as a result of genetic defect.

• British Shorthair

  

  © ZStoimenov/Fotolia

  The British Shorthair is known for both its looks and its typically easygoing and fun-loving personality. The appealing chunkiness of its face and body and its plush, thick fur match its sturdy temperament. The wide-cheeked faces of British Shorthairs appear to be smiling and more expressive than many cat breeds’, and it’s said that they were the inspiration for the wide-grinning Cheshire Cat of Lewis Carroll’s Alice’s Adventures in Wonderland. British Shorthairs are reputed to be doglike in their readiness for fun and games, such as fetching.
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• Siamese

  

  John Gajda/Encyclopædia Britannica, Inc.

  Who can resist the Siamese cat’s pretty blue eyes? These cats have been valued for their unique patterning and outspoken personalities for centuries. Long a status symbol, Siamese cats have been given to dignitaries as gifts. They made their U.S. debut in 1878 when one was given to President Rutherford B. Hayes and his wife by an American consul. These cats are especially known as being very vocal—their loud meows are sometimes mistaken for babies crying!

• Norwegian Forest Cat

  

  © Marc Henrie

  If you like hugging a cat who’s a big armload of fur and can take what you dish out, then the Norwegian Forest Cat is for you. A big cat with big paws and lots of fur, the Norwegian is like a Maine Coon cat’s Viking cousin. The large, muscular, affectionate, and calm Norwegian has a dense and water-resistant double coat and tufted toes and ears, making it the perfect companion for snowshoeing, raiding neighboring countries, and standing atop the dragon head on the prow of a Viking ship.
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• Japanese Bobtail

  

  © Chanan Photography

  Japanese Bobtails are like cats on the front end and rabbits on the back end. Just let that sink in for a minute. It’s almost too cute to handle. Kitties with bunny tails? Sign me up. These adorable critters are native to Japan, and have been around long enough to score appearances in traditional art. Unlike most dogs with "docked" tails, Japanese Bobtails come by their stubby tails naturally. The genetic mutation that causes the tail reduces the number of vertebrae present. And did I mention they like to play fetch?

• Persian

  

  AdstockRF

  Fur, fur, fur. The Persians (called Longhairs outside the U.S.) are perhaps the quintessential "luxury" cat—that is, the cat who expects to be kept in the lap of luxury. They are, however, the most popular cat breed in the world. Although they are known for the pushed-in "Pekingese" nose that many are bred for, arguably the best part of these cats is their pettability. All that fur needs a lot of daily grooming, however, and Persians are prone to kidney disease, so they need frequent ultrasounds.

• Scottish Fold

  

  Psihopat

  While his ears are relatively straight, internet sensation Maru is a Scottish Fold, a breed of cat usually characterized by ears that fold forward and down. The first Scottish Fold was a barn cat discovered in 1961. For show, Scottish Folds are required to have the turned-down ears—but these are a result of a genetic mutation, so not all purebred Scottish Folds have them.

• Gray Tabby

  

  © Lorraine Murray

  The name "gray tabby" describes not a breed but a coat color and pattern. The sporty looks of the gray tabby are peerless. Classic tabbies can, of course, be bred, but part of the fun of cats is in the genetic rock-tumbler that produces random combinations of coloration and patterns. The classic tabby markings are stripes and whorls all over the head, limbs, body, and tail, but mixed-breed tabbies can have "dilute" or broken patterns and, quite often, white chests, undersides and/or paws. The latter is an especially fetching combination and never more adorable than when the cat’s fur is predominantly gray; it’s an understated, neutral look that goes with practically everything—especially a pink nose and a loving personality.

 

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0 يناير 22, 2019

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