History:

Smokes are a rare, but old and established color. First seen at British cat shows in 1860, they were shown in their own class in 1893, rather than as a member of the Any Other Variety classes. In 1900, the Silver and Smoke Persian Cat Society was formed. It later became the Chinchilla, Silver Tabby and Smoke Cat Society (Pond 1972).

There were 30 smokes registered in 1900, and it had declined to 18 by 1912. At the end of the Second World War, the color was almost extinct in Britain (Alderson 1983). One of the most famous early smokes was Mrs. H.V. James's Ch Backwell Jogram, who according to the National Cat Club Stud Book and Register for 1900-1905, took many firsts in the first years of the 19th century (Pond 1972). The first smokes were shown only in blacks and blues. Today, the smoke is seen in black, blue, blue-cream, red, cameo, tortoiseshell, cream, lilac and chocolate. Still trying to achieve recognition is the shaded black smoke.

Cameos were developed quite recently, first bred in the United States by Dr Rachel Salisbury in 1954. These were derived originally from smoke and tortoiseshell pairings (Alderman 1983). Other breedings to create cameos used red, cream, tortie and blue cream Persians with silver or smoke Persians. Cameos were recognized by the ACFA in 1960 and by the CFA in 1961.As early breeders continued with their Cameo breeding programs, shell, shaded and smoke tortoiseshells began to appear. These always female cats are extremely important in any cameo breeding program as they are cameo recessive (genotype), which means they carry the cameo gene. The smoke tortoiseshells were recognized in 1977 by the CFA (Cat World 1986). In 1982, the blue cream smokes were accepted into the CFA. This had far reaching effect of increasing one's chances of blue smokes ( Naviaux).

Often called " the cat of contrasts", it is possible that smokes are the result of crossbreeding black, blue, white and chinchilla Persians. The more recognized theory is that smokes came from a silver tabby mutation. In his article " Breeding Smoke Persians", Donald Martin states that " originally the Smoke came from a Silver Tabby in which the gene for marking mutated and instead of producing black markings on top of a silver coat, the mutation gave a solid black coat on top of the white". ( Green 1968). Although the current standard is brilliant cooper eyes for smokes, smokes originally had green eyes. In the late 1800's breeders began to cross smokes with blues and blacks, which bred in the copper eyes and eventually became the standard. The copper eye color takes about a year to fully develop. If the kitten does not have eyes of some shade of copper by five months old, he will not have deep copper eyes as an adult.

The Smoke Today:

Today, CFA's standard for black smokes states: White undercoat, deeply tipped in black. Cat in repose appears black. In motion, white undercoat is clearly apparent. Points and mask black with narrow band of white at base of hairs, next to skin, which may be seen only when fur is parted. Light silver frill, ruff and ear tufts. Nose leather and paw pads black. Eye color brilliant copper.

Smokes go through many changes in coat pattern and color before the true smoke coloring comes in, which is usually when the kitten is 6-8 months old (O'Hara 1968). Until then, they can be very mottled, at times almost losing the black topcoat entirely, or in reverse coat with the black on the inside and the lighter coat on the outside. Often, they will look almost like "shaded blacks" until their adult coat comes in. When born, smoke kittens are all black without any undercoats. They have gray-white or pure white markings around and above each eye ( referred to as clown lines in the past). The white undercoat usually comes in when the kittens are 10 days to 2 weeks old ( O'Hara 1968).

The dominant colored smoke's coat texture is silky . Dilute smokes tend to have a cottony coat The white undercoat is most prominent in the winter months , although some smokes have been known to hold onto their undercoat to be shown all year round. Most of the time, smokes do not attain their full coat beauty until late December or January and the coat generally loses it's crisp white undercoat around March. Many breeders want to be able to show all year round for points and smokes can be at a disadvantage in this area. Due to the smoke's coat losing it's magnificent undercoat after the winter months, makes it not as popular as other Persian breeds that can be shown all year . It takes much love, dedication and passion for the smoke breed to remain faithful to breeding smokes. As the topcoat and undercoat start to shed and come out, there is more tendency for tabby markings to appear on the face and legs. Rusty coats on smokes are caused by dampness and direct sunlight. Pulling out mats and knots on smokes will cause the new hair to grow in black.

One of the problems in breeding smokes is that smokes can not be color-bred to other smokes for any length of time before tabby markings appear and type disappears (Ramsdale 1964). Smokes are usually crossed back and forth with blacks or blues in order to retain eye color and type. Blacks are preferred for black smokes, as the blue tends to muddy the undercoat and give a bluish cast to a black topcoat (Ramsdale 1964). Many Smoke Persian breeders also feel that breeding smokes to tabbies is unacceptable, as the tabby will bring out the stripes and bars on the smoke coat. When smokes are judged, any tabby markings on the cat are penalized.

Genetics:

Smoke is formed by the combination of the inhibitor gene (I) with the non-agouti (a) - aaI-. The action of I in producing white undercoat is clearly seen in this variety of cat. Ghost tabby marking of dark and light pigmentation may be observed in most kittens if one looks enough at the coat and may persist into adulthood. (Robinson 1999).The extent of the white undercoat is variable and the overall color may be described as smoke, shaded or shell, depending on the amount of tipping and top color. The smoke allele is a simple dominant-recessive gene, and is expressed by the symbol: Chsm. A smoke may be either homozygous (ChsmChsm) or heterozygous - (Ch-Chsm). A cat that is homozygous for smoke alleles will throw only smokes. One that is heterozygous will throw other degrees of tipping or solids, depending upon whether the other allele at that locus is shaded or solid ( Powers 1993).

The dominant inhibitor gene - I - suppresses pigment fed into the growing hair. This results in the typical expression of white hairs with colored tips. Its similarity to the actions of the agouti gene suggest that an inhibitory protein is created in the locus as well. This gene appears to have a greater ability to suppress phaeomelanin pigment than eumelanin pigment, resulting in the prevention of the eumelanin shift. A feature of the gene is the wide varietation of expression. That expression ranges from a barely perceptible white band at the base of the hairs next to the skin, to an almost completely white animal with the pigment restricted to the extreme hair tips. As the melanin inhibitor gene is extremely variable in its expression, it can exhibit impenetrance, resulting in occasional cats with no visible white undercoat that nonetheless breed as smokes ( Robinson 1999).

The silver tabby ( A-I-) exhibits a fairly low level of expression of this gene, while the chinchilla silver (also A-I-) is a fine example of extreme phenotype created through selective breeding. The smoke is the non-agouti form (aaI-). The white undercoat is evident but each hair contains appreciably more pigment due to the lack of the additive inhibitory properties of the agouti factor ( Robinson 1999).

According to Don Shaw's articles, in the 1970 Cats Magazine, the enzyme tyrosinase is necessary for normal production of melanin pigment. This "Enzyme A", as Shaw calls it is temperature sensitive. At normal cat body temperature ( 101.8), full melanin is produced. If the body temperature rises or falls, much of the enzyme is destroyed and will result in a "fever coat" in solid colored kittens. In smokes and other shaded cats, since the enzyme is temperature sensitive, the further from the body core, the cooler the cat, so the more inhibited the production of pigment by Enzyme A. That is why the shaded and smoke cats have heavier concentration of pigment on the top lines, with fading out on the underside. Shaw indicates that smokes have Enzyme A3, which is considerably more temperature sensitive than Enzyme A and less temperature sensitive than Enzyme 1 or Enzyme 2 ( Powers 1993).

The combination of genes I and O results in the cameo and red smoke. The genotype is A-I-O or aal-O for the male and A-I-00 or aal-00 for the female. As the non-agouti allele has no effect on red cats, the difference between smoke and shaded cameos, unlike that between black smokes and shaded silvers, is not due to the genotype at the agouti locus. The parti-color or tortoiseshell cameo has the genotype aal-0o, if the non-red areas of the coat are smoke or A-I-0o, if these areas are silver tabby or chinchilla. The tabby patterns are relatively unimportant in the cameo. The m allele could be involved in producing the darker shaded forms while the M allele is probably involved with the lighter ( Robinson 1999).

There are three shades of cameos accepted at present. The most heavily shaded is the red smoke, also called smoke cameo, with very dense tipping, and appearing solid red from a distance. Next there is the shaded cameo with less intense tipping and then the shell cameo, the lightest shade with minimal red tipping. The major difference between the shaded silver and chinchilla vs. the cameo is the conversion of the black pigment to orange by the 0 gene. The fundamental gene in the creation of these two series of varieties is the inhibitor gene I and similar polygenes are obviously shared between the shell cameo and the chinchilla silver ( Robinson 1999).

The various cream cameos have genotypes identical with the corresponding red cameo with the addition of the dilute (d) gene. The two fundamental constitutions are therefore I-dd0 ( male) and I-dd00 ( female). These occur in the same three intensities of veiling as in the cameo. The dilute particular may be either aaddl-0o if the non-cream cameo areas of the coat are blue smoke or A-ddl-0o, if the areas are blue silver tabby or chinchilla ( Robinson 1999).

Conclusion:

With all it's glorious history, the smokes, or rather smoke breeders, have not kept up with the solid colored Persian type wise ( Green 1968). It is important to breed smokes to more typy or extreme solid Persians to improve type and keep the smokes as competitive as the other Persian breeds. Achieving top quality smokes takes time ,planning, patience and years of perfecting smoke pedigrees. I am grateful for all the dedicated smoke breeders that came before me and hope I can help advance this breed as they did.

Ann Black, RN, MN, FNP.

References:

• Alderson, David. (1983). The Cat. London: Chartwell Books.
• Green, Mrs. Robert. (1968). The Cat of Contrasts. The Cat Fanciers Yearbook 1968
• Naviaux, Barbara. Come to the Smoke Revival. The Cat Fanciers Association Almanac
• O'Hara, Joan. (1968). Smitten With Smokes. The Cat Fanciers Yearbook 1968
• Pond, Grace. (1972). The Complete Cat Encyclopedia. New York: Crown Publishers, Inc.
• Powers, Colleen. (1993, April). Wholly Smokes!. Persian News, 93, 33-34.
• Ramsdale, Jeanne. (1964). Persian Cats and Other Longhairs. New Jersey: TFH Publications.
• Single, Dee J. (1986, September). Cat World, 86, 10-11.
• Vella, C., Shelton, L., McGonagle, J., Stanglein, T. (1999). Robinson's Genetics for Cat Breeders and Veterinarians, Fourth Edition. Oxford: Butterworth-Heinemann.