Calico cats
Encyclopedia
Cat
The cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...
s with a spotted or parti-colored coat, usually predominantly white with orange and black patches. Outside of North America the pattern is more usually called tortoiseshell-and-white. In the province of Quebec, they are unofficially considered a breed by the french-speaking population and called chatte d'Espagne (French for 'Spain's female cat'). Other names include tricolor cat, mi-ke (Japanese for 'triple fur') and lapjeskat (Dutch for 'patches cat'); calicoes with diluted coloration have been called calimanco or clouded tiger.
Calicoes differ from simple tortoiseshell
Tortoiseshell cat
Tortoiseshell describes a coat coloring found mostly in female cats. Cats of this color are mottled, with patches of orange or cream and chocolate, black or blue. They are sometimes called torties...
cats in that tortoiseshell cats have black and orange coats with possible patches of white, whereas calico cats have white-based coats with black and orange patches. Some calico coats have a swirl (called a rosette) on either side of the stomach.
"Calico" refers only to a color pattern on the fur, not to a breed. It is absent from lists of breeds. Among the breeds whose standards allow calico coloration are the Manx
Manx (cat)
The Manx cat , formerly often spelled Manks, is a breed of domestic cat originating on the Isle of Man, with a naturally occurring mutation that shortens the tail...
, American Shorthair
American Shorthair
The American Shorthair is a breed of cat believed to be descended from European domestic cats brought to North America by early settlers to protect valuable cargo from mice and rats...
, British Shorthair
British Shorthair
The British Shorthair is a domesticated cat whose features make it a popular breed in cat shows. It has been the most popular breed of cat registered by the UK's Governing Council of the Cat Fancy since 2001, when it overtook the Persian breed....
, Persian, Japanese Bobtail, Exotic Shorthair and Turkish Van
Turkish Van
The Turkish Van is a recognized cat breed that is known for its unusual love of water and swimming. They were created from the cats native to the Lake Van area of Turkey. The cats of this type are named in Turkish Van Kedisi , in Armenian vana katou or vana gadou and in Kurdish...
.
Because genetic determination of some coat colors in cats is linked to the sex chromosome, calicoes are nearly always female.
Historical migration
As calico cats are not a breed, but a color pattern on the fur which occurs in a non-predictive manner, there is no true historical background concerning calico cats. 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. The proportion of cats having the orange mutant geneMutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...
found in calicoes was traced to the port cities along the Mediterranean in France and Italy, originating from Egypt.
Discoveries
The beginning of serious study of calico cats seems to have occurred around 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 bodiesBarr body
A Barr body is the inactive X chromosome in a female somatic cell, rendered inactive in a process called lyonization, in those species in which sex is determined by the presence of the Y or W chromosome rather than the diploidy of the X or Z...
. In 1959, Japanese cell biologist Susumu Ohno determined the Barr bodies were X chromosome
X chromosome
The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals and is common in both males and females. It is a part of the XY sex-determination system and X0 sex-determination system...
s. In 1960, Mary Lyon
Mary F. Lyon
Mary Frances Lyon, FRS is an English geneticist, who is best known for her discovery of X-chromosome inactivation, an important cytogenetic phenomenon.-Childhood and education:...
proposed the concept of X-inactivation: one of the two X chromosomes inside a female mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
shuts off. She observed this in the coat color patterns in mice.
Although study has continued and deepened, these were the major contributors in the discovery of X inactivation in the early days.
General genetics
Mammals have two sex chromosomes: the X chromosomeX chromosome
The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals and is common in both males and females. It is a part of the XY sex-determination system and X0 sex-determination system...
and the Y chromosome
Y chromosome
The Y chromosome is one of the two sex-determining chromosomes in most mammals, including humans. In mammals, it contains the gene SRY, which triggers testis development if present. The human Y chromosome is composed of about 60 million base pairs...
. A normal female has two X chromosomes and no Y chromosomes and normal males have one X chromosome and one Y chromosome. It is the chromosome that comes from the father which determines the sex of the mammal. The father will either contribute his X chromosome whereby the offspring will be female or his Y chromosome and the offspring will be male.
All female placental mammals seem to have a common trait: they are all mosaics
Mosaic (genetics)
In genetic medicine, a mosaic or mosaicism denotes the presence of two populations of cells with different genotypes in one individual who has developed from a single fertilized egg...
. They all have random patches of X inactivation
X-inactivation
X-inactivation is a process by which one of the two copies of the X chromosome present in female mammals is inactivated. The inactive X chromosome is silenced by packaging into transcriptionally inactive heterochromatin...
from one of their two X chromosomes. This inactivation occurs early in cell development, is random, and is permanent.
Genetics of calico cats
Calico cats are almost always female because the X chromosomeX chromosome
The X chromosome is one of the two sex-determining chromosomes in many animal species, including mammals and is common in both males and females. It is a part of the XY sex-determination system and X0 sex-determination system...
determines the color of the cat and a female cat has two X chromosomes. A common male cat has one X and one Y chromosome. Since the Y chromosome does not have any color genes, there is no chance he could have both orange and non-orange together. One main exception to this is when, in rare cases, a male has XXY chromosomes, in which case the male could have tortoiseshell or calico markings. Most male calico or tortoiseshell cats are sterile
Sterility (physiology)
Sterility is the physiological inability to effect sexual reproduction in a living thing, members of whose kind have been produced sexually. The term may be used in reference to* types of organism, such as the mule, a sterile hybrid;...
due to the abnormality of carrying two X chromosomes.
"In the case of a calico cat, the feline’s parents passed on different versions of X chromosomes genes related to coat color."
The color of calico or tortoiseshell cat
Tortoiseshell cat
Tortoiseshell describes a coat coloring found mostly in female cats. Cats of this color are mottled, with patches of orange or cream and chocolate, black or blue. They are sometimes called torties...
s is determined by the X chromosome(s). Tortoiseshell and calico cats are almost always female because of X chromosome inactivation.
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 genes for a black or white coat on the other, and those can affect or modify the orange mutant gene. 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."
Current issues
It is currently impossible to reproduce the fur patterns of calico cats by cloningCloning
Cloning in biology is the process of producing similar populations of genetically identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments , cells , or...
. "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."
Calico cats may have already provided findings relating to physiological differences between male and female mammals. This insight may be one day broadened to the fields of psychology
Psychology
Psychology is the study of the mind and behavior. Its immediate goal is to understand individuals and groups by both establishing general principles and researching specific cases. For many, the ultimate goal of psychology is to benefit society...
, psychiatry
Psychiatry
Psychiatry is the medical specialty devoted to the study and treatment of mental disorders. These mental disorders include various affective, behavioural, cognitive and perceptual abnormalities...
, sociology
Sociology
Sociology is the study of society. It is a social science—a term with which it is sometimes synonymous—which uses various methods of empirical investigation and critical analysis to develop a body of knowledge about human social activity...
, biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...
and medicine
Medicine
Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....
as more information becomes available regarding the complete effect of random X-inactivation in female mammal.
Folklore
Cats of this coloration are believed to bring good luckLuck
Luck or fortuity is good fortune which occurs beyond one's control, without regard to one's will, intention, or desired result. There are at least two senses people usually mean when they use the term, the prescriptive sense and the descriptive sense...
in the folklore of many cultures. In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, these are sometimes referred to as money cats. The Japanese Maneki Neko
Maneki Neko
The is a common Japanese sculpture, often made of ceramic, which is believed to bring good luck to the owner. The sculpture depicts a cat beckoning with an upright paw, and is usually displayed—many times at the entrance—in shops, restaurants, pachinko parlors, and other businesses...
figurine is almost always a calico cat.
See also
- Bicolor catBicolor catA bicolor cat has white fur combined with fur of some other color, for example black or tabby. There are various patterns of bicolor cat. These range from Van pattern through to solid color with a throat locket...
- Point (coat color)Point (coat color)Point coloration refers to animal coat coloration with a pale body and relatively darker extremities, i.e. the face, ears, feet, tail, and scrotum...
- Tabby catTabby catA tabby is any cat that has a distinctive coat that features stripes, dots, lines or swirling patterns, usually together with an "M" mark on its forehead. Tabbies are sometimes erroneously assumed to be a cat breed. In fact, the tabby pattern is found in many breeds of cat, as well as among the...
- Maltese catMaltese catMaltese cat is a name that is often given to any cat whose fur is either completely, or primarily, gray or blue and is of indeterminate breed. Many cats with such colouration are supposedly present on the island of Malta, which may have given rise to the use of the adjective in this context...
- Deaf white catDeaf white catSome white cats suffer from congenital deafness caused by degeneration of the inner ear. This condition is associated with blue irises. In white cats with mixed-coloured eyes , it has been found that deafness is more likely to affect the ear on the blue-eyed side...
- Cat coat geneticsCat coat geneticsThe genetics of cat coat coloration, pattern, length, and texture is a complex subject, and many different genes are involved.- Genes involved in albinism, dominant white, and white spotting :...
- Tortoiseshell catTortoiseshell catTortoiseshell describes a coat coloring found mostly in female cats. Cats of this color are mottled, with patches of orange or cream and chocolate, black or blue. They are sometimes called torties...
- CatCatThe cat , also known as the domestic cat or housecat to distinguish it from other felids and felines, is a small, usually furry, domesticated, carnivorous mammal that is valued by humans for its companionship and for its ability to hunt vermin and household pests...