Tortoiseshell (cat)
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The tortoiseshell pattern consists of red and black areas of fur and occurs almost exclusively in female cats . It is very rare in male cats (0.43% of all tortoiseshell cats are male cats) and is usually associated with sterility. It is also called tortie (from English tortoise shell "turtle shell") in technical language . If there is a tabby drawing at the same time , one also speaks of a torbie (contraction of tortie and tabby).
The tortoiseshell pattern can also be associated with the dilute gene ; the colors are then blue and cream.
A three-colored cat with a white, black and red patterned fur is referred to by breeders as a tricolor , or as a “tortoise shell with white” or “tortoise with white”, and in Persian cats as calico . Popularly, a cat with this pattern is also called a "lucky cat". In the United States there is the name Money cat , and in Japan this coloring is called Mike ( Japanese 三毛 'three skins' ).
Genetic background
The tortoiseshell pattern follows a single X-linked codominant inheritance : Both the allele for the red and the black coat color are each on one of the two X chromosomes ; the cat is heterozygous for red / black . Red would be dominant over black; However, only one X chromosome is active in a cell , while the other is inactivated during the early embryonic development ( X inactivation ). It can therefore be assumed with a high probability that a female cat that is completely red has the allele for red on both X chromosomes ( homozygosity ).
In heterozygous cats there are regions of the skin where the allele for red is active and the fur is then also red, and secondly regions where the allele for non-red is active and the fur is then black. The distribution of the red and black regions is not genetically determined, but is determined by embryonic development. Two-colored cats are therefore a vivid example of a genetic mosaic . In some cases, the coloration can be such that a tortoiseshell cat is initially mistaken for a monochrome and under certain circumstances can only be recognized by the young that the mother is a tortoiseshell cat.
When a tortoiseshell cat is cloned , X-inactivation of the donor cell persists. In the clone, the same X chromosome is inactivated in all cells, so that it has either only red or only black fur. The first successfully cloned cat, the cat CC , evolved from a tortoiseshell cat with white.
If a male tortoiseshell cat is born, it is usually sterile. Klinefelter syndrome ( karyotype XXY), a genetic XX / XY mosaic, a male phenotype despite the XX karyotype or an instability of the colored ballel in the XY karyotype are possible causes of tortoiseshell coloration in male cats .
The white color of the tri-colored cats is not controlled by the X chromosome, but is based on different alleles for spotting that are controlled by the autosomal c-kit locus ( leucism ).
Superstition
In Japan, the three-colored Japanese Bobtail was the epitome of wealth and power and was bred at the Japanese imperial court at the beginning of the 17th century. Sailors often took a black, white, and red calico cat with them on their ships for a safe journey. In England, too, tricolor cats have long been considered lucky charms due to their rarity. They were also said to protect the house from fire. The following section can be found in Brehm's animal life from 1893:
“A three-colored cat protects the house from fire and other misfortunes, people from fever, and it also extinguishes the fire if it is thrown into it and is therefore called a 'fire cat'. Those who drown them are no longer lucky or are unhappy for seven years; whoever kills them is also out of luck; whoever hits them has to do it from behind. The cat attracts diseases; her corpse, however, buried under someone's doorstep, brings bad luck to the house. "
The Japanese lucky charms in the shape of a cat, Maneki Neko , also known as the waving cat, are usually depicted with a tortoiseshell pattern.
Individual evidence
- ↑ The Tricolor Cat Mystery. In: sueddeutsche.de. August 18, 2015, accessed October 7, 2018 .
- ↑ Christoph Riedel: Pedigree cats - great cats: Heredity and breed description . BoD, Norderstedt 2014, p. 15.
- ↑ Carolyn J. Brown, John M. Greally: A stain upon the silence: genes escaping X inactivation. In: Trends in Genetics . 19 (8), 2003, pp. 432-438. PMID 12902161 . doi : 10.1016 / S0168-9525 (03) 00177-X
- ^ T. Leaman et al .: Male tortoiseshell cats in the United Kingdom. In: Vet Rec. 144 (1), 1999, pp. 9-12. PMID 10028567
- ↑ C. Moran et al .: Fertile male tortoiseshell cats. In: Journal of Heredity. 75 (5), 1984, pp. 397-402. PMID 6481130 .
- ↑ David Gerhold: Three-colored velvet paws: The myth of the lucky cat. In: RPonline. Rheinische Post Mediengruppe, March 14, 2014, accessed on September 7, 2019 .
- ^ Alfred E. Brehm, Wilhelm Haacke, Eduard Pechuel-Lösche: Brehms animal life. First volume: The mammals. Bibliographisches Institut, Leipzig / Vienna 1893, p. 426.
