Golden Colors Of Cats And Their Genetic Basis

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Golden Colors Of Cats And Their Genetic Basis
Golden Colors Of Cats And Their Genetic Basis

Video: Golden Colors Of Cats And Their Genetic Basis

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Video: Cat Colour Genetics: Pt 1 - Solids and Tortoiseshells 2023, January
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Tiger, spotted, marbled cats with a golden hue, no, no, and they are found in urban and rural populations of different countries. However, for a long time such cats eluded the sight of felinologists, if only because the color, which had not been brought to perfection by purposeful selection, did not differ in the warm and juicy gamut characteristic of modern "gold".

Even now, when golden colors have taken off on the crest of fashion, and every club wants to boast of having such cats, it is not uncommon for "gilded" cats to appear at exhibitions, the color of which has not reached full development. In other words, not all that glitters is gold.

What then? The first and main sign of color: from 1/2 (golden tabbies) to 2/3 (golden shaded) or 7/8 (chinchillas) of each guard and integumentary hair in a light or bright apricot warm tone. Shades of this tone in different parts of the cat's body may differ, but in no case should they turn into dull, grayish colors. The most common (not to say, pleasant) addition to the color of golden tabbies and shaded ones are residual ticking stripes on the dyed dark part of the guard hairs, which either "smears" the pattern (in tabbies) or gives a sloppy look to the color (in shaded ones). This deficiency is so common that it is considered almost normal.

British shorthair golden chinchilla, photo photo
British shorthair golden chinchilla, photo photo

Very often there are color variations of cats, intermediate between gold and ordinary black tabbies: the guard hair of such animals is dyed in "gold", but the undercoat is gray. Usually, the eyes of these individuals do not reach the emerald green color characteristic of golden colors.

Among golden cats with a pattern (tabby), there is another variation of the golden color, when both the undercoat is golden and the background of the awn is highly gilded, but the integumentary hairs in the pattern are darkened almost to the roots. By the way, cats of this type never have ticking stripes in the pattern, and the actual "gold" is intense, almost copper color. Unfortunately, the sample of cats of this type is extremely small.

So, among the golden colors, at least three different types can be distinguished, as well as all the options for the transition between them.

How did golden cats go down in the history of felinology?For the first time, a litter of golden chinchilla cats was obtained from silver chinchilla parents. Such cases are not uncommon even now. The breeders were immediately interested in the new spectacular color, and the first years of its existence, golden chinchillas were bred along with silvery ones. Since then, two prejudices have taken root: firstly, only Persians are golden, and only chinchillas or shaded (but not tabby), and secondly, golden color is determined by the presence of the same semi-dominant inhibitor gene (genetic symbol I), which provides silvery colors of chinchillas, shaded cats, silver tabbies and smoky cats. Homozygotes for the recessive allele of the same gene - I - are capable of producing only ordinary black tabbies or monochromatic individuals. It was believed that, according to the mechanism of action, gene I is a melanin inhibitor, that is,prevents the synthesis and accumulation of pigment granules in the hair, both black (eumelanin) and yellow (pheomelanin). Thus, the hairs, with the exception of the earliest grown part, the tip, remain uncolored (white) under the influence of the inhibitor gene. However, it was not possible to explain all the color variations obtained in the silver-gold scale by the work of only one gene, even if it was semi-dominant. Therefore, geneticists-breeders put forward the assumption about the genes of rufism - that is, a group of genes that provide additional synthesis of the yellow pigment - pheomelanin. But even this too vague assumption was not considered satisfactory.under the influence of the inhibitor gene, they remain unstained (white). However, it was not possible to explain all the color variations obtained in the silver-gold scale by the work of only one gene, even if it was semi-dominant. Therefore, geneticists-breeders put forward the assumption about the genes of rufism - that is, a group of genes that provide additional synthesis of the yellow pigment - pheomelanin. But even this too vague assumption was not considered satisfactory.under the influence of the inhibitor gene, they remain unstained (white). However, it was not possible to explain all the color variations obtained in the silver-gold scale by the work of only one gene, even if it was semi-dominant. Therefore, geneticists-breeders put forward the assumption about the genes of rufism - that is, a group of genes that provide additional synthesis of the yellow pigment - pheomelanin. But even this too vague assumption was not considered satisfactory.But even this too vague assumption was not considered satisfactory.But even this too vague assumption was not considered satisfactory.

British shorthair golden chinchilla, photo photo
British shorthair golden chinchilla, photo photo

Moreover, after the Persian golden chinchillas, golden Europeans, golden Siberians, and not only shaded ones, but also cats with a pattern, began to appear rapidly. (The golden British cats, apparently, were not "discovered", but "made" with a mixture of the corresponding Persians.) The search for genes responsible for such a seductive color was continued.

Researchers first of all paid attention to the "Babylonian ranks", that is, the similarities in color mutations in different groups of animals. For example, Siamese cats, Himalayan rabbits, and acromelanist mice all have a color that is genetically determined in the same way. According to this law of parallelism, the dominant “broadband” gene, wb, found in some rodents, was nominated for the role of candidates for genes of golden color.

Bicolors are born from bicolors
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Under the influence of this gene, a wide yellow stripe is formed at the base of the hair, and the animal acquires a golden color. In the case of the action of the normal allele of the wb gene, an ordinary black tabby is obtained, but if an inhibitor gene is added to this genetic background, then a silver tabby is formed. When alleles I and Wb are concentrated in the same organism, silvery or shaded chinchillas are formed.

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Another hypothesis, also based on the parallelism of colors, is that cats have a gene for "golden agouti" (the genetic symbol for Ay), which is characteristic of dogs and mice. In most mammals, well studied genetically, the agouti complex is represented not only by two alleles, that is, gene variants known in cats (A agouti and a - nonaguti), but a whole series of alleles. The so-called "sable" color of dogs, for example, is associated precisely with the action of the "golden agouti" allele and consists in yellow dyeing of the hair (with the exception of their dark ends). If we proceed from the assumption of the presence of the same gene in cats, then further reasoning about the formation of the silvery-gold color range will be similar to those described above, with the difference that the usual agouti factor A will take the place of the hypothetical recessive wb.that currently the most common bigenic theories of gold and silver colors, that is, based on two separate loci (or genetic complexes).

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