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Original title: "White collar, white gloves, white mask." Why is your cat born to "dress" itself? "

(photo Source: Flickr) there are thousands of kinds of cats in the world. If you look closely, you will find that some cats have white claws and white chin hair and look very noble and elegant. Their owners affectionately call them sheriffs and think they are wearing white gloves and white ties.

Why are some cats born with such a unique fur costume? What determines the color of a cat's hair?

The black cat sheriff is real! | the left originates from the network and the right originates from Flickr. Like the appearance characteristics of humans, the hair of cats is also determined by heredity. In general, cats can be divided into two categories according to hair color. All kinds of patterns and colors are formed by random collocation and modification of genes on the basis of these two colors.

The first category is black. Controlled by the gene that produces eumelanin Eumelanin, called B gene, there are three genotypes B, b and b', of which type B is more dominant than the other two genotypes. When a cat has a type B gene, it produces a large amount of true melanin, which gives it a pure black coat color; when a cat inherits the bb or b 'gene, it produces the right amount of true melanin, which gives the fur a rich chocolate color.

Effect of each possible combination of B gene on coat color | the second type of Messybeast is the red line. It is controlled by the gene that produces brown melanin Pheomelanin, called O gene, and there are O and o genotypes. Cats with type O gene produce brown melanin and appear orange, while cats with type O gene do not produce brown melanin, and their color depends on the combination of B genes they carry.

However, the aesthetics of biology is not so simple.

The appearance of cute cats with blue-gray, lavender and cream fur has made the otherwise dark, dull palette lively, thanks to diluted genes, of course.

There are two forms of diluted genes: d and d. Russian blue cats and British blue cats are popular for preserving BB / dd combinations from generation to generation, showing a low-key blue-gray color.

How do fur background colors black, chocolate and cinnamon change to bluish gray and cream by diluting genes? | how do Messybeast hawksbill cats with two-color fur grow up?

In fact, cats and humans have sex chromosomes XX, XY,X chromosomes containing fur color indicators. Female cats have two X chromosomes, so they receive two sets of instructions about coat color in each cell, but the two instructions are not exactly the same, some black lines and some red lines.

During the earliest development of a kitten, an X chromosome becomes inactive, and the inactivated X chromosome is completely random in each cell. As a result, in such a chaotic and disorderly situation, there is a unique tortoiseshell color, so that the kitten has long black hair and orange hair.

Hawksbill turtle and three-flower cats are not specific cat breeds, but most breeds have this color, but hawksbill turtle cats have the highest abandonment rate in the world because of their appearance. | Pxhere now we have a common fur color left to discuss-white!

White is related to three alleles of KIT gene: wild type allele (w-does not change the original coat color), masking gene (W-can mask all the original coat color), white spot (S-randomly produces white spots, s-does not change the original coat color). Cats with the w gene will not have any effect, and their fur color is still dominated by other colors.

The W gene overrides any instruction to produce the fur pigment gene, making the cat appear all white. But there is another kind of white cat that needs to be distinguished-albino cats controlled by albino genes. The difference between the two is that white cats can synthesize melanin, and they still have pigment in their eyes, which can be blue, green, yellow, orange or light brown. Albino cats, on the other hand, have light blue or light pink eyes.

Cat: Ah, I don't understand. | Pxhere white spot gene (White Spotting gene) has a dose effect. When carrying one copy of S gene (Ss), the white area of the cat's body will not exceed 50% of the total area; when carrying two copies of white spot gene (SS), the white area of the cat's body will be more than 50% of the total area; cats without S gene or ss gene will not show white.

Coat color effect produced by different doses of genes | the position of Messybeast white spots on the body is random, but it also follows a certain rule, that is, white spots always tend to be distributed in areas far from the back. This is because although its melanocytes move fast, but they divide very slowly, abdomen, claws and other places do not produce enough melanin, so it becomes white, which is often said to grow without "ink".

It is said that every time a mangosteen is eaten, a cat loses its white gloves! | in fact, in addition to cats, many other animals have deep back and light belly fur colors, such as tigers, foxes, penguins, manta rays and sharks. This is actually a feature of most animal evolution-reflection camouflage (Countershading). As early as 1896, the famous American portrait painter Abbott Handerson Thayer coined the term and explained: "Animals are painted by nature, and the darkest places are often the places that are brightly illuminated by sunlight, and vice versa."

(image source Pxhere, Flickr)

Under normal circumstances, light will be projected from above, if it is an animal with a uniform white body, there will be a brighter white above the animal and a darker shadow below, making the object chromatic aberration and showing a three-dimensional effect, thus making the animal more obvious.

(image source YouTube) but if it is an animal with a dark upper part and a white lower part, when combined with light, it can balance the amount of light directly on the body, reducing the contrast between the upper and lower parts of the body, making it easier for animals to integrate into their surroundings.

(Tuyuan YouTube) this camouflage is important for predators or prey: the former needs to reduce its presence to sneak up on prey, while the latter needs to hide itself from predators.

The wild cats that live in the forest, like their ancestors, have a coat that is good for camouflage and survival. Wild cats with white claws are too conspicuous in front of predators and prey to hide, making it easy to be eliminated by nature in the long run.

However, when humans began to domesticate cats, the unique white claws became a cat feature that made people "scream", love to put it down, and take the initiative to choose cats. In this way, the "white gloves" of domestic cats have been preserved from generation to generation.

Source of the cover: Flickr reference:

[1] Stelow et al, The relationship between coat colors and aggressive behaviors in the domestic cat, Journal of Applied Animal Welfare Science, 2015.

[2] David, V.A., Menotti-Raymond, M., Wallace, A.C., Roelke, M., Kehler, J.A., Leighty, R.R., Eizirik, E., Hannah, S.S., Nelson, G., Sch ä ffer, A.A., et al. (2014). Endogenous retrovirus insertion in the KIT oncogene determines white and white spotting in domestic cats. G3 (Bethesda) 4, 1881-1891.

[3] http://messybeast.com/colour-charts.htm

[4] http://messybeast.com/cat-genetics-basics.htm

[5] Montague M.J., Li G., Gandolfi B., Khan R, et al. Comparative analysis of the domestic cat genome reveals genetic signatures underlying feline biology and domestication. Proc. Natl. Acad. Sci. USA. 2014 Tanjia 111 Pluto 17230-17235. Doi: 10.1073/pnas.1410083111.

[6] G ó rska A, Drobik-Czwarno W, G ó rska A, Bry Bry J. Genetic Determination of the Amount of White Spotting: A Case Study in Siberian Cats. Genes (Basel). 2022 Jun 2: 13 (6): 1006. Doi: 10.3390/genes13061006. PMID: 35741768; PMCID: PMC9223243.

[7] Mort, R., Ross, R., Hainey, K. Et al. Reconciling diverse mammalian pigmentation patterns with a fundamental mathematical model. Nat Commun 7, 10288 (2016). Https://doi.org/10.1038/ncomms10288

This article comes from the official Wechat account: take Science Home (ID:steamforkids), written by A Xian, revision: Ziv

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