The Selkirk Rex is a breed of cat with highly curled hair.

Background

The Selkirk Rex is distinct from all other Rex breeds. Unlike the Devon Rex and

Cornish Rex The Cornish Rex is a cat breed, breed of domestic cat. The Cornish Rex only has down hair. Most breeds of cat have three different types of hair in their coats: the outer fur or "guard hairs", a middle layer called the "awn hair"; and the down ha ...

, the hair is of normal length and not partly missing. There are longhair and shorthair varieties. It differs from the LaPerm in that the Selkirk Rex coat is plusher and thicker. While the LaPerm gene is a simple dominant, the Selkirk gene (Se) acts as an incomplete dominant; incompletely dominant

allele An allele is a variant of the sequence of nucleotides at a particular location, or Locus (genetics), locus, on a DNA molecule. Alleles can differ at a single position through Single-nucleotide polymorphism, single nucleotide polymorphisms (SNP), ...

pairs produce three possible

genotype The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a ...

s and

phenotypes In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properti ...

heterozygous Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mos ...

cats (Sese) may have a fuller coat that is preferred in the show ring, while

homozygous Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mos ...

cats (SeSe) may have a tighter curl and less coat volume. The Selkirk Rex originated in

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

, USA in 1987, with a litter born to a rescued cat. The only unusually coated kitten in the litter was ultimately placed with breeder Jeri Newman, who named her Miss DiPesto (after a curly-haired character in the TV series '' Moonlighting'' played by Allyce Beasley). This foundation cat was bred to a black Persian tomcat, producing three Selkirk Rex and three straight-haired kittens. This demonstrated that the gene had an

autosomal An autosome is any chromosome that is not a sex chromosome. The members of an autosome pair in a diploid cell have the same morphology, unlike those in allosomal (sex chromosome) pairs, which may have different structures. The DNA in autosome ...

dominant mode of inheritance. All Selkirk Rex trace their ancestry back to the cat Miss DiPesto. Jeri Newman named the breed after her stepfather, "Selkirk," making this the first (and currently only) breed of cat to be named after an actual person. The breed has been developed in two coat lengths, long and short. It is a large and solidly built breed, similar to a British Shorthair. The coat is very soft and has a woolly look and feel with loose, unstructured curls. The head is round, with large rounded eyes, medium-sized ears, and a distinct muzzle, whose length is equal to half its width. An extreme break, like that of a Persian, is a disqualifiable fault. American Shorthairs,

Persians Persians ( ), or the Persian people (), are an Iranian ethnic group from West Asia that came from an earlier group called the Proto-Iranians, which likely split from the Indo-Iranians in 1800 BCE from either Afghanistan or Central Asia. They ...

, Himalayans, Exotic Shorthairs, and British Shorthairs have been used as outcrosses to develop this breed. The American Shorthair has now been discontinued as an outcross, except in The International Cat Association (TICA). The breed was accepted by The International Cat Association in 1992, the American Cat Fanciers Association in 1998, and the Cat Fanciers' Association in 2000. In Cat Fanciers' Association (CFA) and in Australia, all outcrosses are scheduled to be discontinued in 2015. The breed is accepted in all colors, including the pointed, sepia, and mink varieties of albinism; bicolors; cinnamon; silver/smoke; and the chocolate and lilac series. This breed has an extremely dense coat and high propensity for shedding. Unlike other Rex breeds with reduced amounts of hair, the Selkirk Rex is not recommended for those who might be allergic to cat allergens. The temperament of the Selkirk Rex reflects that of the breeds used in its development. They have a lot of the laid-back, reserved qualities of the British Shorthair, the cuddly nature of the Persian, and the playfulness of the Exotic Shorthair. There are no known health problems specific to the Selkirk Rex breed. They are a robust breed. Breeding towards proper head structure is necessary to prevent kinking of the tear ducts, resulting in tear run down the front of the face, or muzzle creases that can result in

dermatitis Dermatitis is a term used for different types of skin inflammation, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened ...

on the face. Like other Rex breeds, irritation of the inside of the ear by curly fur can occur, increasing the production of ear wax.

Homozygous Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mos ...

cats (with two copies of the dominant Selkirk Rex gene) may have a tendency towards excessive greasiness of the coat, requiring increased frequency of bathing. Other health problems may be inherited from the outcross breeds used, including

polycystic kidney disease Polycystic kidney disease (PKD or PCKD, also known as polycystic kidney syndrome) is a genetic disorder in which the renal tubules become structurally abnormal, resulting in the development and growth of multiple cysts within the kidney. These ...

from Persians and hypertrophic cardiomyopathy from British Shorthairs. Responsible breeders screen their breeding cats for these diseases to minimize their impact on the breed. In the UK, all Selkirk Rex registered with the

Governing Council of the Cat Fancy The Governing Council of the Cat Fancy (GCCF) is a cat registry, established in 1910 and the largest organisation that registers pedigree cats in the United Kingdom. It was formed from a small number of cat clubs which were registering cats a ...

(GCCF) for breeding are genetically tested for Polycystic Kidney Disease or are from two genetically tested parents.

Genetics

The Selkirk Rex is defined by an

dominant woolly rexoid hair (ADWH) abnormality that is characterized by tightly curled

hair Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and ...

shafts. A splice variant in the gene KRT71 was found to be associated with the curly coat

phenotype In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological propert ...

. KRT71 is a crucial gene for

keratinization Keratin () is one of a family of structural fibrous proteins also known as ''scleroproteins''. It is the key structural material making up scales, hair, nails, feathers, horns, claws, hooves, and the outer layer of skin in vertebrates. Kera ...

of the hair follicle. An

of this

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

is also responsible for the hairless (hr) Sphynx and the Devon Rex (re) hair. Three

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, ...

s in KRT71 have now been identified in cats, forming the allelic series, KRT71SADRE > KRT71+ > KRT71re > KRT71hr,Gandolfi B, Alhaddad H, Joslin SE, Khan R, Filler S, Brem G, Lyons LA. A splice variant in KRT71 is associated with curly coat phenotype of Selkirk Rex cats. Sci. Rep. 2013;3:2000. . where SADRE is the suggested locus designation for the Selkirk autosomal dominant rex 21

References

{{Library resources box, lcheading=Rex cat Cat breeds Cat breeds originating in the United States Rex cat breeds