I. V. Shustrova Cats. genetics and breeding. Pigmentogenesis and genetics of colors. Ending

There are two chemical varieties of melanin: eumelanin - produces black, chocolate, cinnamon, blue, lilac and fawn colors (black group of colors), and phaeomelanin - produces colors in the red-yellow-orange and cream range (red group colors).

The genes responsible for color are located on the X chromosome, which also determines the sex of the animal. Cats, like women, have two X chromosomes in the last pair of genes, cats have one, but they have a Y chromosome, like men. Colors whose genes are located on the X or Y chromosomes are sex-linked. Therefore, the types of colors depending on gender may differ slightly: for example, only females should be tortoiseshells, and males - only as an exception: such males turn out to be infertile, because Inheritance of the tortoiseshell gene by a cat is associated with other genetic mutations. Sometimes genes are associated with other defects, for example, white cats with blue eyes are more likely to be born deaf. Albinos are an anomaly: they have a pigment deficiency, but may not have any other health abnormalities. And color point cats often develop strabismus.

Patterned

Any color can be patterned.
The shape of the pattern is determined by a series of T (tabby) genes. And such genes are present in the genotype of absolutely every cat. But, as you know, not every cat is striped or spotted. It's all about another gene - A (agouti). This gene either “turns on” or “turns off” as the hair grows, coloring the hairs in transverse rings with alternating dark and light tones. Decoding the colors of cats begins with a search for two genes in the genotype - T and A. If there is at least one A, the cat will be patterned. If there are two aa in the genotype (homozygous recessive set), the fur coat will be colored evenly, since without ticking (coloring the fur in stripes) a pattern is impossible. So, what does the color of a tabby cat mean? The answer is obvious: the cat is a carrier of the dominant agouti gene (A). Now let's look at the tabby gene (T):

Ta (Abyssinian) is dominant to T (stripes), and T is dominant to Tb (marble). But there are still spots! But with them it’s more complicated: either there is a specific gene that allows spotting to appear, or the spots are the result of the work of a group of modifier genes that “break” the stripes (the latter is more likely).

Patterned “silver” and “gold”

Patterned colors look extremely beautiful and impressive if breeders pay attention not only to improving the pattern itself, but also the background. Thanks to the work of an additional group of polygenes, the yellow-brown undercoat can be given a bright golden-sandy hue, making it “golden,” and if the patterned color is combined with the dominant Silver gene (I), then the beige tone of the undercoat changes to bright white and the result is “silver.”

A table that clearly shows how, as a result of various selections, the background shade can differ using the example of a spotted pattern

“Cold” tone of the undercoat, especially on the body, and slight yellowness on the face and paws (BRI n 24)

Bright, richly “warm” tone of the undercoat. This cat has gold in her ancestry, if not for her orange eyes, she could very well be one. (BRI n 24)

For chocolate color, the golden shade of the background is natural; the chocolate gene gives a “warm” tone not only to the main color, but also to the background. This is why it is so difficult to work with chocolate silver; it is extremely difficult to achieve a clear contrasting pattern and a clean background without yellowness

(BRI b 24)

The “warm” tone of the undercoat of this golden animal was obtained as a result of many years of work by breeders. Please note that the polygenic complex that gives the golden hue to the undercoat indirectly affects the main pigment, as a result of which the pattern on the body becomes brown instead of black. Nevertheless, genetically it is precisely black, which can be seen in the places of the greatest accumulation of pigment - the tip of the tail, paw pads, and the rim of the nose. (BRI ny 24)

Peculiarities

The striped color appeared in modern domestic cats thanks to their wild ancestors. The heterogeneous color of the coat with darkened elongated areas allows wild felines to better camouflage and monitor prey. There are no two identical individuals, even in the same litter, the color of each animal is unique in its own way.

Tabby cats have a characteristic "M" on their forehead, made up of stripes. This color is called tabby. Tiger cats have strong intelligence and good health. Scientists have identified a relationship between striping and the development of the immune system.

The character of minke whales is calm and balanced. Such pets love to learn something new and dominate the house where they live. Until old age, the tabby cat will retain its energy and love of games.

Popular long-haired cat breeds.

Australian mist

Australian Smoky cats have a small, strong body and short hair. This is one of the most striped cat breeds; these are the most common representatives. The main color is gray to brown. Australian Smoky cats love to play and prefer to lead an active lifestyle.

The price of an Australian Mist kitten is 45 – 50 thousand rubles.

American Wirehair

The breed is so named for its coarse, short hair. The hairs of cats of this breed are really harsher to the touch than those of other pets. The brindle tabby color is most often found on a smoky coat.

American wirehair kittens cost 14 thousand rubles, adult pets over 1 year old cost 70 thousand rubles.

The biggest cats - list of breeds.

American Curl

The breed's common tabby coloring is not the only notable feature. American Curl ears have unusual tips that turn outward toward the back of the animal.

Depending on the pedigree, American Curls cost 10 – 30 thousand rubles.

This is interesting! Tabby coloring is often found in outbred cats. Like their more expensive brothers, these cats have good immunity and are very smart.

List of the fluffiest cat breeds.

Asian tabby

From the name of the breed you can understand that the color of the representatives will be striped. Asian tabbies were bred artificially in the UK. The pets have a bright brindle color and an easy-going character.

On average, Asian tabby cats cost 60 thousand rubles. and higher.

Jungala

One of the youngest breeds, which has not yet received proper distribution. In 2001, the Jungal breed was developed by crossing Siamese, Abyssinians and the American Shorthair cat.

The cost of Jungal kittens reaches 50 – 60 thousand rubles. for a young individual, but it is difficult to find representatives of the breed in the CIS countries.

Kurilian, American Bobtail

Breeds with a short rudiment instead of the usual tail. This cat breed is similar to a tiger with its classic striped coloring. The color of the coat is from gray to brown, earthy.

Middle-class bobtails are valued at 30 thousand rubles, the cost of exhibition animals reaches 80 thousand rubles.

Read more about the Kuril and American Bobtail.

Maine Coon

A very popular breed of especially large size. The weight of a Maine Coon can reach 14 kg. Externally, representatives of the breed resemble a lynx: there are tufts on the ears, but instead of spots there are tiger stripes.

Kittens aged 2 months of the Maine Coon breed cost 35 thousand rubles, the price of adult cats is higher and reaches 60 thousand rubles.

Manx

Manx cats are famous for their variety of colors. Striped individuals are also common. One of the first breeds discovered that does not have a full tail.

The average price of a Manx cat is 30 thousand rubles.

This is interesting! Scientists estimate that more than 600,000,000 domestic cats live with people. About 80% of them are striped in color.

List of cat breeds without a tail.

Pixiebob

A hybrid breed similar to a lynx with tufted ears, but without a tail. The common color is silver, smoky with stripes. Depending on the pedigree and characteristics of the offspring, pixie bobs cost 30 – 60 thousand rubles.

Toyger

The name of the breed is very similar to the English “tiger” - tiger. This is a real domestic tiger, reduced to an acceptable size and safe for companionship with humans. Representatives of the breed are very active and aggressive, looking unusually similar to wild tigers.

Toyger kittens cost from 60 thousand rubles. and above, exhibition specimens – 200 thousand rubles.

List of cat genes responsible for mutations of ears, tails and paws

Note: the genetics of the tails of all bobtails except the Japanese are unknown, presumably bob tails are inherited polygenically; The American Ringtail's tail is probably determined by a recessive gene (designation unknown).

List of cat genes responsible for rare mutations

P. M. Borodin: summary of previous episodes

Exactly 40 years ago I published my first article about the genetics of cats in the journal Chemistry and Life. In it, I convinced the reader that all the beauty of genetics and its laws can be seen not in peas, not in fruit flies, but in cats.

At that time, cat genetics consisted mainly of describing colorful phenotypes and their inheritance. In principle, this was enough for breeding and maintaining breeds and conducting genogeographic studies. Later it turned out that some of the then hypotheses about the inheritance of even simple and obvious color traits were, to put it mildly, incorrect. The path from the gene to the trait in most cases was either unknown at all, or was generally established in the mouse and was, without much embarrassment, attributed to the cat. We knew then that the cat's genome contained DNA, but that was where our understanding of its molecular genetics ended. Forty years ago it was clear that the cat was related to the lion and the tiger, but the details of this relationship were lost in the mists of time.

In 1989, my article entitled “Cats and Genes: Ten Years Later” was published in the same “Chemistry and Life”. From it, readers learned what cat chromosomes look like under a microscope, understood how the first genetic maps of this animal were constructed, and were convinced of their striking similarity to human chromosome maps. At the end of the article, I promised to write a sequel called “Cats and Genes: 20 Years Later.” But he didn’t keep his promises.

But he wrote a book where he collected all the achievements of cat genetics of the 20th century. It was published in 1995 and has since been republished countless times, including in the “Masterpieces (sic!) of Popular Science Literature” series. This book was longlisted for the Enlightenment Prize and received a special diploma from the Club of Scientific Journalists with the correct wording “For the effective use of cats to popularize science.”

In 2009, my article “Cats and Genes: 30 Years Later” was published in the magazine “SCIENCE First Hand”. In the 2000s, cat genetics experienced a boom. The cat genome was sequenced and partially annotated, and the first cloned and transgenic cats were obtained. The use of comparative genomics methods has made it possible to reconstruct the main stages of the evolution of mammals in general and cats in particular. It turned out that the last common ancestor of the cat, horse and bat lived in the world relatively recently (about 79 million years ago). I wrote about all this in my article. Runet picked up and widely spread the news about a common ancestor, honestly referring to me: “A cat and a horse have a common ancestor,” Pavel Borodin.” This is how I became the common ancestor of a cat and a horse.

Another 10 years have passed since then. The time has come to write “Cats and Genes: 40 Years Later,” which is what we did together with Lyubov Malinovskaya. Soon after Lyuba appeared in our laboratory, I asked her to help prepare the next edition of “Cats and Genes.” She did it brilliantly. I collected all the new publications on cat genetics, corrected all the errors and typos that had been passed from edition to edition for years. Soon she bought herself first a cat, then a male cat, and later took courses as a young felinologist and registered her own cattery. I am deeply convinced that it was working with my book that revealed to her the modest charm of cats and cat science, although she categorically denies this. Let this remain on her conscience.

It is important that we wrote this article together. This serves as a guarantee that the tradition will not be interrupted, and the reader, fifty or a hundred years later, will receive another article about cats and their genes every decade.

Shaded and chinchilla colors of the British cat

The next group of silver colors: shaded and “chinchilla” (shell).

If “smoky” colors look light, then shaded and chinchilla colors look almost white, with a characteristic “spraying” at the very tips of the hairs. In cats with a shaded color, this “spraying” occupies only a sixth of the hair, and in individuals with a chinchilla color, even less - an eighth. Naturally, no one measures the length of a hair with a ruler, much less 1/6 or 1/8 of its color. And anyway, we call all such elegant pussies chinchillas. The following points should be noted regarding shaded and shell colors.

1. Both colors are coded as “smoky” colors, but with the numbers 11 – shaded and 12 – chinchilla (shell). For example, BRI ns11 – black, shaded. Outwardly, she looks white, with a black “spray”, and her paw pads, the rim of her nose and the rim of her eyes should be completely black.

2. Both colors mean that there should be no closed stripes on the limbs, tail, or chest (such stripes on the chest are called a necklace). Shaded cats should have shaded hair on the head, ears, sides, back and tail.

3. Chinchilla colors must have bright green eyes. Shaded, that is, slightly darker, have the right to have yellow (or orange) eyes. Only then the eye color coding is then added to the color coding: 62, for example, BRI ns11 62.

No less interesting are the golden colors (coded by the letter y, which is indicated by analogy with the letter s in the designation of “silver”). However, this is even more rare for the British breed.

The chin, belly and lower part of the tail should be painted a pale apricot color, the nose - brick, while a transition to black or dark brown is considered quite acceptable. The paw pads of animals of the color in question are black or dark brown, and their eyes are green.

British chinchilla cats look amazingly rich and elegant. Their fur is similar to a fox fur coat. The chinchilla was developed in the early 1970s. English breeder Norman Winder, who crossed the Persian chinchilla with the British shorthair. The breeder was attracted by the luxurious silver coat of the chinchilla and the power of the British. The experiment was a success: in 1973, Winder demonstrated a new breed at an exhibition, which was called British black with tipping (“spraying”). This color was recognized in 1980 in England by the board of directors of the cat lovers club.

How to calculate the color of a kitten

For this purpose, a Punnett grid is used. In it, the alleles of the male are written down along the vertical square, and the alleles of the female are written down horizontally. Inside the square, a lattice with corresponding variations is obtained. A special calculator will help the breeder calculate the color of the future litter.

Color calculator

In order to calculate the color of future kittens, you must indicate:

• color of female and male;
• what gene they are a carrier of;
• genotype code.

Based on the entered data, the program calculates the approximate number of kittens of a particular color. To correctly compile a genotype code, you need to know how primary colors are encrypted, their shades, the presence of lightening or solid (solid), pattern, ticking, etc. To compile a color formula, almost the entire Latin alphabet is used. Other factors affecting coat color are also taken into account:

• density;
• length;
• thickness of the hair shaft.

Cats that are colored the same can have different genotype codes (formulas), and vice versa - outwardly different colors can have the same coding. For example, black coat color may have the following formulas:

1. Homozygous: aaBBDD; aaBBDd - has a “hidden” blue tint.
2. Heterozygous: aaDbDD - with a hint of chocolate; aaBbDd - carrier of blue and chocolate (mixing them gives a purple tint); aaBbIDD - cinnamon color carrier (ivory - I); aaBbIDd - carrier of the color “cinnamon” and blue (forms the fawn color).

The coding “aa” means non-agouti - the absence of alternating light and dark stripes on all hairs of the coat and uniform coloring of the shaft from base to tip. Long-haired hair may lighten slightly at the end.

Some colors are not available in the calculator because they do not correspond to the Maine Coon breed standard.

Explanation of meanings

The formula contains letters and numbers. The letters (they are located at the beginning of the formula) indicate the base color of the Maine Coon's coat. The accepted EMS encoding indicates the corresponding color in English or French:

• W - white;
• N - black;
• D - red;
• A - blue;
• E - cream;
• F - tortoiseshell;
• G - creamy blue (bleached tortoiseshell).

The pattern on the Maine Coon's fur is also encrypted, but using numbers. The lower the number in the designation, the more white the color:

• 01: main color - white, colored spots are located on the head, shoulders, tail (van);
• 02: white with colored points located on the head, shoulders, along the spine, on the tail (harlequin);
• 03: half of the wool is white (bicolor);
• 09: White points are localized only on the paws or chest.

Maine Coon stripes can have different shapes, locations and thicknesses:

• 22: brindle - directed from the back to the stomach (vertically) and outline the entire body;
• 23: classic (marble) - they are large and twist in spirals on the sides of the animal, which creates the effect of veins on the marble;
• 24: spotted - located throughout the body, can be large or small in size, intermittent, paws and head - striped;
• 25: ticked - located only on the cat’s face, this type of pattern is not typical for Maine Coons and is considered a defect, because it does not correspond to the breed standard.

When starting the calculation, in the “Father’s coat color” column, select the corresponding main color and mark the presence of tabby. In the column “Shade of the mother’s coat,” select her main color and note the presence of tabby or tortoiseshell (scattered multi-colored spots). In the following column, the presence of the gene is separately noted for the father and mother:

• Chocolate - chocolate;
• Dilute - diluted;
• Homozygous Tabby - the cat inherited stripes from both his father and mother.

The calculator displays the genetic formula in the appropriate window and calculates the probability of the appearance of any color in kittens, for example:

• father: blue tabby, carrier of the homozygous tabby gene has the formula BBdd0-AA;
• mother: main color chocolate, tortoiseshell, diluted - bbDdOo-aa.

Males of the following colors may appear:

• black tabby - 12.5%;
• blue tabby - 12.5%;
• red tabby - 12.5%;
• cream tabby - 12.5%.

Females of the following colors may appear:

• black tabby -12.5%;
• blue tabby - 12.5%;
• black tortoiseshell tabby - 12.5%;
• creamy blue tabby – 12.5%.

Knowing the color of the parents and their ancestors (to determine hetero- or homozygosity), you can use a calculator to predict the coat color of the offspring or select a pair to obtain the desired shade in kittens.

Colors of the “black” group

The B (black) gene is responsible for the normal formation of black pigment. Under the influence of the b gene, the pigment oxidizes - a brown color is obtained. But B suppresses the action of b (capital letter - dominant, lowercase - recessive gene). Thus, BB and Bb cats look the same black, and if the kitten inherited two bb from its parents, it will be brown (rich chocolate) in color. Kittens inherit one chromosome from each parent. Therefore, when crossing individuals BB plus Bb, “chocolates” will not be born - there is nowhere to get two bb.

The bl gene oxidizes the pigment even more strongly than the b gene, resulting in a light, warm shade of brown called “cinnamon.” But b and B suppress bl, so the kitten must get bl from both parents, otherwise it will not be a cinnamon.

When the genetic codes for cat colors include D (d), we are talking about strengthening or lightening the pigment. Gene D makes the color rich and allows the pigment to be densely distributed in the fur: cat B_DD is black. The d gene “mutes” colors, forming less bright, calm shades: cat B_dd is gray. But kitten B_Dd will be black, because gene D is dominant to d and blocks it.

Kittens will turn out purple if they inherit two “weak” genes from their parents: bl (chocolate) and dd (lightening). Thus, lilac is bleached chocolate.

British red color standard

There is a uniform standard of coat quality and color for all British Shorthairs. Felinologists are trying to preserve this indigenous breed unchanged. Therefore, experts carefully monitor all experiments aimed at diversifying the colors of cats.

1. The coat is short, elastic, silky. In red color, stiffer guard hair is allowed, which should not fit tightly to the body.
2. Bright red British cats have an undercoat of the same shade as the main coat. Bald spots of a different color and uneven coloring are not allowed.
3. The chin, tip of the tail and a small area on the belly may be slightly lighter than the base coat shade. In pedigree breeding, such a transformation is not welcomed, but at exhibitions experts are loyal to it.

Additional requirements apply to eye color, paw pads and nose:

1. The pupil is always colored in honey, orange or copper tones.
2. The color of the skin of the nose and pads is darker than the base color - brick, terracotta or bleached brown.

In red British cats, the tabby pattern will always be contrasting. There should be clear lines on the chest and neck. The same pattern starts from the corners of the eyes and covers the cheeks. On the paws and tail there are distinguishable encircling rings of the primary color.

Acceptable variations and deviations in British Reds

All colors containing red in the British are divided into several categories.

The first includes standard solid colors (solid). In this case, the wool will be dyed evenly along its entire length. The British acquired this color as a result of crossing with the Persian longhaired breed.

In the future, such inter-tribal unions were prohibited due to the increase in hair length, but the color was fixed and consistently transmitted with proper breeding.

The next category is red smoky, which is formed when the pigment is unevenly distributed throughout the hair. The root part remains light, only 4/5 of the length is colored.

The fur of red British cats seems evenly colored, but when moving, lighter areas of the hair are revealed, resulting in the effect of a shimmer of shades.

Another color option is silver-red, shaded. Here the wool is pigmented to 1/3 of its length, and 2/3 remains bleached. At the same time, the nose, eyes and lips of shaded red British kittens have a contrasting dark edging.

The next variety of red is the red chinchilla. The pigment appears only at the tip of the hair (1/8 of the length), and the rest of the hair is not dyed. The term “cameo” is used for British people with this coat color.

The acromelanic color-point (red-point) has a lighter shade of body, in contrast to the mask on the face, the tips of the ears, the ends of the paws and the tail.

British Red kittens can be born bicolor or particolor. This is a combination of white and red colors, which is considered traditional for many cat breeds. They differ only in the amount of white wool.

• from 30 to 50% white - bicolors;
• from 50 to 90% white - particolors;

The rarest combinations for cats of the British breed:

1. Harlequins are 90% white and 10% red.
2. Vans - maximum white color. Only the tail and a few markings on the head near the ears remain in red.

Genetics of cat colors

Whatever book on cat genetics an amateur opens, everything there, as a rule, begins with a description of genes and chromosomes, at least briefly describes the mechanism of their transmission, etc. Although these descriptions are made extremely brief, the owner, who usually has no affairs before everything happens, it is not interesting to delve into them. Often the desire for simplicity and brevity of presentation forces the author to lose sight of some fundamentally important things. As a result, he may face sharp criticism from professionals, since from their point of view the description may turn out to be fundamentally incorrect (i.e., so approximate that, having mastered it, an inexperienced reader will remain hopelessly far from a true understanding of the situation). Worse than that, this reader may also fall into error, religiously believing in apparent simplicity. Usually the owner is interested in a simple, purely applied problem: how to determine the color of the future kittens of a given cat from a given cat. For such owners, many books provide color charts. There is even a program that allows you to roughly calculate what kind of kittens these parents will produce. The main drawback of the program is that it gives color options without giving the user any idea about the calculation method and what result is most likely and why. If the owner wants to select a partner for his cat in advance in the hope of getting kittens of the desired color from him, he will have no choice but to stupidly go through the options until he finally comes across the one he needs. Therefore, in my description I will simply outline a method that allows you to determine the color of kittens by the color of the parents and vice versa - to calculate one of the parents by the color of the kittens. You should know that in the cells of the body of each cat, without exception, there are nine pairs of so-called alleles that determine the basic properties of its color. The cat receives one allele from each pair from the father; the other is from the mother. All alleles are designated by Latin letters. There can be many alleles that affect the same color feature (for example, the size of white spots) in nature. Each such “bunch” of alleles is called an allele series, and all alleles in the series are designated by the same letter with different indices. Although there are many alleles in the series, a particular cat can only receive 2 and no more. For example, in general, in cats you can find 5 types of S series alleles responsible for the size of white spots:

• Sv – large white spots merging with each other, almost white cat;
• Sp – large white spots, partially merging with each other, the cat is motley;
• S – a cat whose white spots occupy from half to 2/3 of the entire skin;
• s – cat without white spots;
• si – a cat with small white spots, for example, a small “shirt front” on the chest.

However, any given cat can still only get two of these five alleles - for example, a pair of Svs, or Spsi, or ss, etc. It is these two alleles of this cat that will determine what the white spots on its coat will be - large, merging with each other, or, conversely, very small (up to the complete absence of white spots in a cat that is lucky enough to pull two identical alleles from the “heap” - s and s).

If a pair consists of two identical alleles, the cat is said to be homozygous for the [allele name] gene. If the alleles in a pair are different, the cat is said to be heterozygous for the gene [name of one of the two alleles of this pair]. For example, a cat whose cells contain the allelic pair ss is said to be homozygous for the s gene. And a cat that has both the s allele and the S allele is heterozygous for each of them: Ss - the cat is heterozygous for the S gene and heterozygous for the s gene. In some series there may be a lot of alleles, and, accordingly, there may be a lot of variants of allelic pairs. Many alleles are not yet known to scientists. However, what is known will be enough for the cat owner to at least not get kittens of an undesirable color. The relationships of the alleles that make up a pair may be unequal. For example, a cat that received the W allele (white color) from its father, and the w allele (colored color) from its mother, will have the color determined by the allele designated by the capital letter W, that is, it will be white. The fact is that the W allele is dominant in relation to the w allele, and the w allele, accordingly, is recessive in relation to W. In this case, W completely suppresses the influence of w. Usually, when describing the alleles that make up a series, they are arranged in order of decreasing dominance. That is, the “strongest” allele comes first, followed by the “weaker” one, and so on until the allele, which can be suppressed by any of the previous ones if paired with it. In addition, dominant alleles of a series are indicated by a capital letter, and recessive ones by a lowercase letter; this is especially convenient if there are only two alleles in the series: one dominant, the other recessive.

Below is a list of known allelic series. Each cat necessarily contains two alleles from each series. These two alleles form a pair in her body, in which one allele is received from the father and the other from the mother. In the future, by analyzing the pairs, it will be possible to get an idea of ​​what color a cat with such pairs of alleles will have. For convenience, allelic pairs are given in descending order of the strength of their effect on color. For example, if a cat has the dominant white color allele W (allelic pair No. 1), the cat will be white regardless of what other allelic pairs it inherits. A cat homozygous for the Siamese color cs allele will have a temperature-dependent (so-called acromelanic) color: light coat with darker markings on the face, ears, paws and tail: all other alleles, with the exception of W, can only affect the shade of light coat and color of marks. The effect of the O allele (the presence of red or cream color in the color), included in the third series, also cannot be suppressed by the effect of other alleles, with the exception of W or the allelic pairs caca and cc (i.e., a non-white cat or a cat carrying the O allele , will definitely have at least a speck of red or cream color in their color). 1. Alleles of the W series (White). The presence or absence of a dominant white color is determined.

2. Alleles of the C series (Color), also known as the albino series. Depending on which pair of alleles of a given series a cat has, it may be completely colored, have a color whose intensity depends on temperature, or remain uncolored (an albino cat).

The existence of the albinism genes c and ca is questionable. If these genes existed, it would be possible, although rare, for completely white kittens to be born to non-white parents. However, in the vast majority of cases, such “white” kittens either darken with age, turning into colorful cats (that is, cats of Siamese colors), or it later turns out that they were born from an unplanned mating of a non-white mother with an enterprising street gentleman, a carrier of the dominant white gene color W. If a cat received the cb gene from one of the parents, and the cs gene from the other, thus becoming the happy owner of the cbcs allelic pair, then this means that she is a carrier of the Tonkinese color, intermediate between the Burmese and the Siamese.

3. The allelic series O (Orange) determines whether the cat's color will contain red (fawn). This is a specific sex-linked allele; it differs from others in that it does not have a pair as such. The concept of “allele o, recessive to O” is arbitrary and is introduced simply for convenience.

Very rarely, tortoiseshells also appear among cats. As a rule, this color in a cat is associated with a genetic pathology. When analyzing the color of the expected kittens, it is convenient to remember the following rules related to the specific inheritance of the O series allele: 1) Mating a red cat with a non-red cat cannot produce red cats 2) Mating a red cat with a non-red cat can only produce cats of tortoiseshell color 3) When mating a red cat with a non-red cat, only red cats will be born.

4. Alleles of series A (Agouti). Allows or prohibits the appearance of a pattern, the nature of which is determined by the T series alleles (T and Mc).

5. T series alleles (Tabby). Determine the nature of the cat's pattern. Previously, it was believed that there were 4 alleles in this series – Ta > T > tsp > tb:

However, recently, due to new data, the 4 genes responsible for the nature of the pattern have ceased to be classified as the same allelic series. Now the T series has only 2 genes: Ta and t. The first gene, dominant Ta, determines, as before, the Abyssinian striped color. The second, recessive t, determines the color with one pattern or another (not striped). The nature of the pattern depends on two other genes, called the Mackerel series genes - Mc (striped color) and mc (marble color). It is assumed that the dominant Mc gene is not able to completely suppress the effect of mc; the result is spotted heterozygotes that inherit the Mcmc pair.

6. Alleles of the S series (Piebald spotting), or white piebald. Determine the presence and size of white spots. The alleles of this series are determined with a large degree of convention. There is no consensus among felinologists about them.

7. Allelic series B (Black). Determines what pigment the cat's hair will be dyed with - normal black or oxidized - chocolate or cinnamon (cinnamon).

8. Allelic series D (Dilution). Determines whether the color will be saturated, bright, or will be weakened, pale - for example, cream, not red, blue, not black, lilac, not chocolate, etc.

9. Allelic series I (Inhibitor) (another name is Sv (Silver, Silver). Determines whether the base of the cat’s hair will be colored or lightened.

It is not difficult to guess that the cats of our cattery - silver shaded and chinchillas - also carry this gene. However, it should be noted that the silver I gene is responsible for the formation of not only silver, but also smoky (smoky) colors. If a cat carries the allelic pair aa (that is, is a “non-agouti”), then if the I gene is present, it will be smoky (smoky). In smoky cats, the base of the hair is lightened by less than 1/3 of the length, so at rest the cat looks completely colored. And only when it begins to move does the heterogeneity of color become noticeable and is an extremely spectacular sight. In reality, the patterns of inheritance of silver are much more complex. It is not just gene I that is responsible for the formation of the colors of the silver (and gold) group, but a whole polygenic complex, the composition of which has not yet been thoroughly elucidated. There are several theories designed to explain the genetics of silver colors, but so far none of them is able to answer all the questions of breeders involved in this complex color variation. In this article, all these theories will not be considered, since such details are not very interesting to a person who does not intend to seriously deal with silver. Therefore, from the next page we will move directly to the definition of colors and answer the question “How to use this data to solve practical problems”, giving specific examples. Read more

Cinnamon - red tortoiseshell color in the British

Tortoiseshell coloring is common in British cats. It is formed by a harmonious combination of evenly colored red and black hairs. But in the case of ginger cats, cinnamon (cinnamon) replaces black and goes with any shade of red.

There are no strict rules regarding the size and number of spots in the British tortoiseshell cat color variety. It is genetically impossible to predict how they will lie on the wool, and therefore any arrangement is allowed.

In tri-colored British tortoiseshell cats, white is added to the two standard spot colors (red-black or cinnamon). Such animals are sometimes called patchwork animals, although this definition does not accurately describe their appearance.

Usually female kittens are born with a tortoiseshell color. However, nature sometimes experiments unsuccessfully, and cats become the owners of an additional chromosome (XXY). In this case, they are also born “turtles” and, most likely, will be infertile.

Acromelanic colors

Cat (Mekong Bobtail) tabby point color

Cat (Mekong bobtail) color blue-cream-tortie-point (tortoiseshell)

Cat (Mekong bobtail) chocolate point color

• Colorpoint (from the English color - color and point - limb) - belongs to the group of acromelanic (temperature-dependent) colors, and is a form of albinism. This group of colors is characterized by a slightly colored, light (white to cream) body and darker paws, tail, muzzle and ears. There are varieties of point colors: seal point (from the English seal - seal) - a very dark gray, almost black color;
• blue point - “blue” (dark gray);
• red point - “red” (red);
• chocolate point - brown;
• cream point - creamy;
• tortoiseshell; tortoiseshell;
• tabby point - striped.

Colors of the “red” group

The O gene is responsible for “red” colors, from a bright almost brick shade to barely noticeable cream tones. The O gene is found only on the female chromosome, so a cat (XY) can carry only O or only O, but in the genotype of a cat (XX) there can be different combinations (OO, oo or Oo). Lowercase o is a recessive gene suppressed by O. Moreover, O is also dominant in relation to B, i.e. suppresses black colors. Thus, a cat that received the O gene from its mother will definitely be red (of course, if there is no W gene, which suppresses color). And a cat can be born red, and like this: BBOoDD (the first O suppresses B, the recessive o “cannot cope with the second B” - we get a tortoiseshell color).

If DD is adjacent to OO, the orange colors of the cats will be sunny and bright. If dd, the fur will acquire a delicate cream tone, since dd lightens not only black (B), but also red color.

Domesticating a cat: where, when and how

The main events in the macroevolution of the cat family were described in detail about 20 years ago. In the last decade, interest has shifted to the more immediate history of cats: the history of their domestication and interaction with humans.

Genetic studies have shown that all domestic cats are descendants of one single species - the wild cat Felis silvestris

(Driscoll
et al
., 2009). This species is widespread throughout the Old World: from Scotland to South Africa and from Spain to Mongolia and has several subspecies.

At the same time, at the DNA level, all domestic cats are practically indistinguishable from the steppe cat F. s. lybica

 - a subspecies found primarily in the Middle East. Fossils belonging to the steppe cat have been found mainly in South Asia and Southern Europe. It is assumed that for many millennia, from the Neolithic to the present, these cats lived mainly in Asia Minor (part of modern Turkey).

The earliest archaeological evidence of the coexistence of humans and cats was found in Cyprus and dates back to 7–8 thousand BC. e. Since none of the Mediterranean islands, besides Sicily, have ever had native populations of cats, cats could only get to Cyprus with settlers from the Middle East. Apparently, cats were domesticated in the so-called Fertile Crescent

about 10 thousand years ago - ​it was at that time that people founded their first settlements in this legendary Middle Eastern territory, which is often called the cradle of civilization.

Thus, man created a completely new habitat for wild animals. Garbage heaps around villages provided the rodents with a free table and home. And the cats came for the mice - but not all of them. At first, there was a strict selection of animals tolerant to humans that could coexist next to him. Why F. s. lybica

became the only subspecies of wild cat that was domesticated?
Because he was in the right place at the right time. As agriculture spread beyond the Fertile Crescent, F. s.
lybica spread along with it, preventing local feral cat populations from joining their feeding grounds - ​trash heaps.

Colors with white spots

White areas may appear on any colored spot. Sometimes their presence is mandatory, and in other cases it is a serious fault or even a disqualifying defect (see the standard of the specific breed).

So, white areas appear due to the action of the dominant white spotting gene S. Moreover, the white area is larger if the cat is homozygous, that is, SS. Heterozygous Ss individuals tend to be more colorful. With ss, there are no white spots at all (except for a small white area under the chin, which appears under the influence of other, “secondary” genes).

There are many modifier genes that affect the location, shape and number of white spots. Unfortunately, the genetics of cat colors does not yet provide a clear answer to the question of which genes and how they influence the degree of spotting. For this reason, working with colors such as van, harlequin and bicolor is quite difficult. It is no easier for those who strive to get perfect “socks” or an even white “mask” - even two excellent parents give birth to kittens with “tight” socks or “masks” that go beyond the desired boundaries.

There was a retrovirus here

The cat, like many other animals, has mutations caused by the introduction of a retrovirus into the gene. And they lead to the appearance of white spots on the body.

In general, the size of white spots on a cat’s body varies widely: from white socks to when the whole cat becomes one continuous “white spot.” It was long thought that the latter phenotype was determined by the dominant white mutation
W
(
White
).
Spots of all other sizes were considered a manifestation of semi-dominant mutations in another gene – ​S
(
Spotting
).
However, in 2014 it turned out that all variants of white spotting are caused by different mutations in the same W
(
White spotting
) gene (David
et al
., 2014).

Protein product of the normal W

ensures the migration of various embryonic cells derived from the neural tube to their destinations.
Among these cells there are melanocytes
, which produce pigments that color the fur and iris of the eye.
Mutations in the W
disrupt the migration and division of the progenitors of these cells, but to varying degrees. The special beauty of these mutations is that they arose one after another, and one from another as a result of the introduction of a retrovirus.

It all started about 3 million years ago, when between two introns of the W

a retrovirus with a size of more than 7 thousand nucleotides was inserted.
This led to a partial breakdown of the gene - the ws
. Cells containing the defective protein migrate to their destinations more slowly than normal cells. Therefore, those areas of the skin where they do not manage to arrive in time remain white. In heterozygotes the delay is insignificant and the spot is very small, in homozygotes it is larger.

Then, during evolution, the retroelement

- ​Only one small fragment of about 700 nucleotides remained from it.
This is how the dominant white mutation W
. But it didn’t make it any easier for the carriers of such a stripped-down retro element. Vice versa. The new mutation, unlike the previous one, not only inhibits the migration and growth of neural tube derivatives, but almost completely blocks them.

Many mutations of white spotting are known in many mammals. It is noteworthy that many of them are caused by mutations in genes corresponding to the W

cats. And in almost all cases where molecular analysis was carried out, it turned out that these mutations were also caused by the introduction of retroviruses. Moreover, each species carried its own retrovirus. What attracts them there so much - who knows?

spotted tabby

A color in which there are separate spots on the body, ideally clear and not merging, uniform on the sides and back. It is formed with the help of the main Tabby genes and a complex of polygenes that “tear” the pattern into separate spots. Spotted and striped colors often form multiple transitional forms, and all these options are always classified as spotted color, because the stripes tend to “tear” as the animal grows older. Therefore, spotted is the most common color among the British patterned. Marble color is less susceptible to the action of “tearing” polygenes, because this is a wider and denser pattern, so only marble that is completely torn into spots is classified as a stain, while marble that has only been slightly exposed to polygenes will look like marble. In any case, the spotted pattern clearly shows which color was used to form the spot.

This is true for all patterned colors - they value the correctness and clarity of the pattern. And also, according to the standard, a patterned animal must have a warm undercoat tone, which can vary from light sand to rich beige.

How did the leopard get its spots?

We suspect, although we cannot prove it, that the same mechanism of cyclic activation-inactivation of genes is also involved in the formation of periodically repeating patterns (stripes, rosettes and stains) on the body of cats, which are united by the term “ tabby

"*. The genes that control one or another variant of the pattern are well known. What is unknown is how they do it.

* There are different (irreconcilable) interpretations of how to write this word in Russian: tabby (approximately 63 million), tabby (108 thousand) or tabby (103 thousand).
We have always written tabby and will not deviate from our principles. The two most common patterns are brindle

(
mackerel
) and
marbled
(
blotched
).
The brindle color was inherited by the domestic cat from its ancestors - most of its modern wild relatives have the same pattern. It is controlled by the Ta
(
Tabby
), which encodes
transmembrane aminopeptidase Q
(Kaelin
et al
., 2012).
This enzyme is involved in controlling the diffusion of various substances in the intercellular space. Three different mutations are known that disrupt the structure of this protein, which in homozygotes lead to the same result - the development of marbled coloration
.

We know that in dark areas of the coat black pigment predominates, and in light areas yellow pigment predominates. The ratio of these pigments in the hair depends on the combined action of two pairs of genes: A

(
Agouti
) and
E
(
Extension
) on one side, and
Edn3
and
Ednrb
on the other.
We also know that the basis of the pattern on the body of the embryo is established 1-2 weeks before birth. But we don't know how this happens. Why are some groups of cells designed to produce dark hair, while others are designed to produce light hair? How and why do changes in the amino acid sequence in transmembrane aminopeptidase Q
lead to changes in the relative position of these cells?

It may very well be that the mechanism of cyclic activation-inactivation of genes is involved in the formation of the pattern. Almost 70 years ago, the great mathematician Alan Turing tried to answer the question posed even earlier by the great poet Rudyard Kipling: “How did the leopard get its spots?” Turing proposed a simple reaction-diffusion model in which stripes and spots are formed automatically if the color of each cell depends on the interaction of two diffusing active substances - an activator and an inhibitor. One can (and would like to) think that in the development of a cat embryo there is a moment when transmembrane aminopeptidase Q

regulates the diffusion and distribution throughout cells of such compounds that regulate the process of pigment production.

The interaction of activators and inhibitors with target tissues also directs the development of cat paws. The order of future fingers (from thumb to little finger) on a limb depends on the SHH

(
Sonic Hedgehog
), encoding a transcription factor.
The latter is involved in the development of not only the limbs, but also the lungs, teeth, some structures of the brain and spinal cord, etc. The SHH
is so important that almost any mutation of it leads to catastrophic consequences, including the death of the embryo.

It is obvious that in each of the structures the SHH

works slightly differently, producing as much protein as is needed in that particular location.
Normally, it works intensively in the area of ​​the future little finger. In the middle of the nascent hand, its activity gradually decreases, and in the area of ​​the thumb the gene does not work at all. SHH
activity controls several dozen enhancers.
When the enhancer is mutated, the gene begins to actively work in some cells of the future thumb, so that they begin to consider themselves a separate phalanx and form a sixth digit. This developmental anomaly, polydactyly
, is quite common in some cat breeds (Lettice
et al
., 2008).

Interesting facts, beliefs and signs about black Britons and more

The black breed of British cats traditionally arouses interest and curiosity. The signs accompanying these animals are diverse not only in nature, but also in geographical location.

1. The black cat is the only animal that has its own holiday. It was founded by Italian cat lovers and falls on November 17th.
2. “It will be unlucky if a black cat crosses the road” - this is not the common belief in all countries. Black Britons are very lucky. In England, they are endowed with positive properties, and the woman who has such a cat will always be the center of attention.
3. The Irish believe that the charcoal anthracite cat brings wealth and prosperity.
4. Even superstitious British sailors willingly took black cats on risky voyages. They believed that animals of this color bring good luck.
5. In Russia there has always been an ambivalent attitude towards black cats. Having met them, in the old days people were baptized and cursed the evil one. But at the same time, they believed that black cats scared away thieves and guarded the house.
6. Of all the breeds that have been officially registered in the world, only 22 have representatives of pure black color. The British Shorthair is one of them.

There is also an interesting observation: the population of black Britons is larger in cities than in rural areas. According to one version, this is due to the fact that black cats adapt better to urban conditions than their tabby or tortoiseshell counterparts.

Such “fatal” Britons, as a rule, are created by wealthy people, extraordinary personalities, prone to exaltation. They rarely live alone; the doors of their home are usually open to numerous guests.

It has been noticed that even the British, who are reserved and selfish by nature, show sociability in such conditions and often become the center of attention.

Future plans: designer cats

Having discussed the main achievements of cat genetics over the past decade, let’s try to look into the future and predict what the article “Cats and Genes: 50 Years Later” will be about.

Today, the International Cat Association recognizes 71 breeds, the Cat Fanciers Association - ​44, and the International Feline Association - ​43. This does not mean that you can add up these numbers and find out how many cat breeds there are. This only means that cat breeders cannot agree with each other. In addition, the question of what is considered a breed is practically insoluble, it is filled with so many genetic, zootechnical and commercial problems and conflicts of interest. Let's just say that there are quite a lot of breeds. Most of them are newly created, based on individual mutations or a combination of several mutations on the genetic background of older breed groups.

Now we are close to creating designer cats - ​obtaining animals with pre-planned properties. We already have all the tools. We know their genome, we know how to clone them, create transgenic animals. Finally, we have a good tool for gene editing: CRISPR/Cas9

and its modifications allow changes to be made to the desired parts of the genome. The only question left is: what changes do we need?

No, let's start from the other end. We definitely do not need changes that will bring suffering to the “edited” animals. Therefore, we will not make any dwarfs or pug cats. Giants too. Firstly, because they already exist - ​look at Maine Coons

! And most importantly, because body size, like many other quantitative traits, is controlled by many genes, each of which makes a negligible contribution to the trait. We quite successfully change such traits through selection. Editing the many genes that control them is extremely expensive and practically useless.

Therefore, we must understand what we want and choose our targets accurately. And then use the law of homological series by N.I. Vavilov - ​similar species have similar variability - ​and knowledge of the genomes of the cat and its relatives. A cat does not have the phenotype we need, but a dog does; We look for a canine gene with the desired mutation, find its feline homologue, and make the necessary changes to it. Ready.

So, we want new, hitherto unknown colors and shapes in cats. For example, Shar-Pei cats, or Dalmatian cats, or even bodybuilding cats, like the Belgian Blue Bull... Applications are accepted. No, no, we were joking. We will never do this ourselves. We have only outlined the prospects for editing the cat genome. And now let's return to the very origins of the inextricable bond between a cat and a person.

Genetics of the red (red) color of the British

The British Shorthair breed allows for approximately 250 different color combinations, with solid colors playing a major role. Ginger cats are not unique here, they are often found in litters and were once even quantitatively ahead of the blue-gray color that is considered traditional for the British.

All the tools of the genotype take part in the process of color formation: chromosomes and genes, alleles, loci and pigmentation.

1. The main role in the formation of the red color in the British is played by the pigment pheomelanin - elongated ellipsoidal granules that reflect light in the range of red, yellow and orange shades.
2. Genes are a library of hereditary data that is passed on from parents to offspring and continues the chain of ancestral connections ad infinitum.
3. Alleles come in different forms that genes can take on. They are located on certain parts of the chromosomes - in the example of red British cats, this is a very important point.
4. Locus is the location of a gene (allele) in an ordered list of chromosomal compounds.

There are 19 pairs of chromosomes in a cat's set. They store the hereditary instructions, and any deviation from the norm ends in an uncontrolled mutation. British redheads are not subject to this risk, as they are an ancient breed with an established genotype.

Genes and chromosomes that influence the formation of red color are distributed as follows:

1. The O (orange) gene is responsible for the production of the red pigment pheomelanin in the British (and not only in them). It has only one permanent locus attached to the X chromosome, which determines the sex of the future kitten.
2. The O gene exists in 3 alleles: OO (natural red), Oo (red and black tortoiseshell British), oo (red is blocked and does not cause pheomelanin pigmentation). The final example in practice means only one thing - the cat will be black.
3. For ginger cats, there are 3 color combination options: OO, oo and Oo. For red British cats, only 2 options are possible - O and O, since they have one X chromosome.
4. According to the laws of genetics, a British cat inherits the orange gene from its mother. Therefore, in a pair with a red mother and a blue-gray father, male kittens will definitely receive the properties of the red gene, and the female cats will be tortoiseshell, cream or blue.

All British red coats have a tabby pattern on their coats. It is formed under the influence of the A gene (agouti) and exists in two alleles: dominant A and paired homozygous aa. In the second case, agouti suppresses another important component of the genotype - the T (tabby) gene, which is responsible for the ornamentation on the fur coat.

The unique property of the red color is that aa (not agouti) has no effect on it. Therefore, all red British cats are always tabby.

The L gene is also involved in the formation of red color. Thanks to him, purebred British cats have short and thick hair.

Why are sphinxes bald and rexes curly?

In addition to point mutations, cats also have mutations caused by deletions ( deletions)

), doubling (
duplication
) or insertion (
insertion
) not of individual nucleotides, but of entire DNA fragments.
These mutations often arise due to failures in the process of exchanging sections of chromosomes ( crossing over
), which occurs during the formation of germ cells.

Several mutations of this type have been found in cats in genes that are responsible for the synthesis and “maturation” of keratins

– ​complex and durable fibrillar proteins that make up the hair.
Disturbances in their structure lead to hairlessness (in sphinxes
) or curly hair (in different variants
of rex
).

In Devon Rex cats, curly hair is caused by a complex mutation in the KRT71

(Gandolfi
et al
., 2010). It includes the loss of DNA fragments in two introns and two insertions in one of the exons. As a result of the insertion of additional amino acids, the structure of keratin changes, which reduces its strength. Changes in introns, it would seem, should not affect the structure of the protein product of the gene, since they are cut out during mRNA maturation. However, such mutations can change the activity of the gene, affecting the splicing process and/or the stability of the RNA read from the gene.

The same gene KRT71

There is also a point mutation - ​replacement of the nitrogenous base guanine with adenine, which leads to the appearance of a stop codon.
As a result, a shortened keratin molecule is synthesized, which, through complex interactions with other proteins, completely deprives the homozygous carriers of the mutation - the Canadian
. It is surprising that the multi-pass mutation of the Devon Rex “only” folds their fur into rings, and replacing one single “letter” with another completely deprives the sphinxes of their fur.

The structure of keratin can change due to mutations not only in the keratin gene itself, but also in the genes responsible for the process of “maturation” of this protein. Thus, the Selkirk Rex owes its curly hair to mutations in the SADRE

(
Selkirk Autosomal Dominant Rex
), which leads to the loss of five amino acids from the keratin protein, the product of the
KRT71
(Gandolfi
et al
., 2013).

Is it only cats?

There is a persistent myth that only cats can be carriers of tortoiseshell coloring - due to the fact that their sex chromosomes look like XX and make it possible for both black and red colors to appear simultaneously. It is not true. It is also not entirely true that, according to statistics, for every three thousand tortoiseshell cats, only one cat of this color is born - and that one is somehow sick, defective and practically sexless.

Tortoiseshell cat or tortoiseshell cat?

The quirks of nature are much more diverse and sophisticated than our understanding. Genetic solitaire games sometimes produce unpredictable results that are difficult to explain from a scientific point of view. For example, felinologists claim that the birth rate of tricolor cats directly depends on the region of their residence - scientists have not yet found an explanation for this phenomenon. But statistics on this matter, alas, are inaccurate—systematic studies have not yet been conducted.

Tortoiseshell cats

Contrary to popular belief, tortoiseshell - calico - cats do exist. But in order for the “female” color to appear, the cat must have a certain gene anomaly: the formula of their sex chromosome set is XXY. Such males are usually sterile, although there are exceptions.

Quite a lot of tricolor chimera cats are known. They can be anatomically and behaviorally similar to cats, practically do not mark their territory, do not react to females in heat and, accordingly, do not give birth to offspring. Calico-colored cats are more common than “tortoises”; they are usually cryptorchids - but that’s a completely different story.

Since the nineteenth century, felinologists from different countries have described many tricolor cats. Unfortunately, most of them were not only sterile, but also did not live long, since along with the genetic mutation they received various serious diseases.

Ears, paws and tail - these are my documents!

So far, we have considered the influence of genes on the formation of the color and structure of fur and whiskers. The paths from genes to these traits are quite short and direct.

How do genes control the development of complex morphological characteristics - ears, paws, tail, coat pattern? Here the pathways are much more complex, tortuous and interesting, and they are controlled by many genes working in concert. Coordination is ensured by transcription factors that are synthesized at the right time and bind in the right place to the regulatory regions of different genes, triggering long cascades of molecular interactions. Mutations that alter the development of these morphological characters are usually found in the genes encoding these particular transcription factors.

Let's start with the tail. At one time, the donkey Eeyore complained bitterly that few people “understand about tails. They have no imagination. For them, the tail is not a tail, but just an extra portion of the back.” In fact, these “they” were essentially right. The tail and dorsal vertebrae arise from the notochord of the embryo, and their formation is controlled by the same set of genes.

Brachyury gene plays a leading role in all these processes.

. It controls the synthesis of a transcription factor that binds to the regulatory regions of many genes involved in the development of the back, including the neck and tail. This protein begins to be synthesized at the earliest stages of embryonic development, determining the orientation of the head-tail and back-belly axes. And gene mutations lead to quite serious consequences.

In tailless cats

Isle of Man and their American relatives found four different mutations in the
Brachyury
: three point substitutions and one duplication combined with a deletion (Buckingham
et al
., 2013).
Each of them leads to the synthesis of a shortened protein. Heterozygotes have enough of the “right” protein to ensure normal development of the embryo, but not its tail. But homozygotes die in the early stages of pregnancy, since the work of the entire network of genes dependent on the Brachyury
goes haywire.

With its pom-pom tail, the Japanese Bobtail

is due to mutations in the
HES 7
, which plays an important role in the formation of body segments in vertebrates (Xu
et al
., 2016).
This gene is capable of self-regulation: the protein it encodes suppresses the activity of the HES gene itself 7
. When the protein is destroyed after some time, its synthesis resumes. Thanks to this cyclicity, segmentation of the embryo’s body occurs, including the formation of a chain of vertebrae.

The Japanese Bobtail has a point mutation in this gene that destabilizes the HES 7

. The mutant protein breaks down faster, the cycle time is shortened, and the segments are very short. Some do not have time to form at all or merge with each other. An ordinary cat's tail consists of approximately 22 vertebrae, while a bobtail's tail consists of 14–21. The length of the tail can vary, and in homozygotes it is the shortest.

Character of British pets

Representatives of the British breed belong to the category of pets with a difficult character.

1. Sociable, but do not allow familiarity. You can pick up a British cat only if she is currently in the mood for it. Any violence or action against the will is regarded as an insult. The cat may proudly walk away, or it may bite.
2. The Briton is not prone to active group games. He will most likely stay in a safe place and look down on all the fun.
3. Very persistent in expressing their own demands. There are times when cats of this breed do not eat for a long time just because they want to change the place for their bowl.

There is a tendency towards aggression in the behavior of British Shorthairs. But it is never groundless. If the cat does not feel discomfort, then it will not terrorize the household with its bad inclinations.

Varieties

As mentioned above, striped color is characteristic not only of purebred cats, but also of ordinary yard cats. Nevertheless, scientists have identified several main breeds of pets that are characterized by a striped color:

• British Shorthair - for such cats the most characteristic color is mackerel gray;
• Scottish - tabby is considered the most beautiful color of cats;
• Siberian - these domestic animals with long hair are characterized by striped-spotted coloring;
• Maine Coon – Maine Coons are most often brown;
• Norwegian Forest cat is quite large in size, and its striped coat has water-repellent properties;
• Asian tabby cat is smooth-haired;
• American Bobtail – the coat can be either short or long;
• Kurilian Bobtail – you can often see red and gray tabby cats;
• American Curl – the coat has a pleasant silky texture;
• pixie bob - stripes on the coat are most often colored in dark shades.