History and origin of chocolate and lilac colorings
The article by B. J. Fox, the manufacturer and holder of a famous American nursery "Foxy" for Himalayan and Persian cats begin with the real, emotional hymn of Persian and Himalayan cats with chocolate and lilac colorings. The desire of most holders to get Persian cats that are carriers of gene of a chocolate color, chocolate-Point Himalayans and entirely colored Persians is clear enough. Himalayans with lilac marks - lilac-Points - and absolutely colored lilacs are more attractive to holders because appear to be the most rare and precious colorings. One can't help being admired by these delicate color tones: "they are so beautiful that one sight will ultimately bring you become a holder of such a cat" - B. Fox wrote.
"These colors, - B. Fox notes, - haven't long been recognized by most holders and referees, considered to be defective, and those who persisted in holding them regarded as outcasts and found themselves isolated. Ultimately, persistency, and mainly, cooperation of nurseries and their holders that worked over this colors won the battle. "The spirit of cooperation triumphed among holders!"
History and origin of chocolate and lilac colorings
Grand-champion list of lilacs and chocolates, both with marks and entirely colored ones is still very short. Himalayans (Persian cats with Siamese color) were recognized by CFA as self-dependent breed in 1957. Later it included cats with solid colors chocolate and lilac. In following 37 years only 9 grand-champions chocolate-Points, 3 lilac-Points, one chocolate and one lilac (4 of them are from a Cactusway nursery and two - from Thailand) were registered. In 1984 Himalayans were deprived from their status of a breed and included in a Persian breed as sub-breed (Himalayan Division), and solid chocolates and lilacs have joined the main Persian breed.
Where do chocolate and lilac colors (chocolates and lilacs) among longhaired cats come from? They appeared due to efforts of three holders that began independently: Brian Sterling-Webb, Briarry nursery in England; S. M. Harding, Mingchiu nursery in England; Regina van Wessem, Siyah Gush nursery in Holland. Later these three nurseries worked together and mated their animals intensively. Then they imported mixed lines from these nurseries in USA were continued inbreeding.
Briarry Bruno was the first longhaired chocolate male cat, registered by English cat-fancies. His father was a shorthaired chocolate that is nowadays called "Havana Brown" in GCCF (the Governing Council of the Cat Fancy, England). By that time his color was called a chestnut-brown. Strong Persian type of his granddad Foxburrow Frivolous was combined with a Siamese color distribution (color-Point) of his grandmother that was Siamese by her mother and chestnut-brown by her father. B. Sterling-Webb began his work with color-Points in 1947. Before him a chocolate-Point color has been defined as undesirable among seal-Points and have been rejected. "The color didn't inspired and wasn't realized because of its' amazing beauty" - a famous holder Betty White said forty years later. Only in 1950 the standard for chocolate color registration was defined.
S.M. Harding and B. Sterling-Webb both raise the first longhaired lilac cat Mingchiu Lilac? A cat derived from Briatty Bruno. The first lilac-Point in English list, the Mingchiu Sula Three - the great-granddaughter of Briatty Bruno was also the result of cooperation of Harding and Sterling-Webb. It is the mixed line of chocolates/lilacs, the result of cooperation of two English nurseries that have appeared in USA for the first time and was subjected to a subsequent inbreeding.
At that time Regina van Wessem, independently of English holders have raised her own line of longhaired chocolates and lilacs. In Holland the black longhaired male cat was received as a result of breeding of a female of an unknown genotype and blue-eyed white Persian cat and then it was mate to his mother. This resulted in a Siyah Gush Cheng Sen, a brown longhaired cat. After Regina van Wessem's death, the Hoog Moersbergen nursery kept up her work. The Holland line had somewhat another, darker chocolate tint than Briarry/ Minghiu but the better type. This line has also appeared in America at the beginning of 70ths. One of the most famous cats in the chocolate line is Willem van Hoog Moersbergen. It's the combination of Briarry/Mingchiu and Siyah Gush lines as a single Hoog Moersbergen. Thus, American holders have received both English and Holland lines along with a combination of Holland and English (1969-1973).
Phenotype and genotype of chocolates and lilacs
The exhibition standard CFA defines the chocolate color of solid colored Persians in a following way: "Rich, warm, chocolate-brown, expressed along from the root to the tip of hair", the tip of nose should and pads should be brown. Chocolate-Point should have an ivory colored body with no darkening, and spots of a "milk chocolate color of a soft tone", tip of nose and pads are brown-pink. As a matter of fact there're two kinds of chocolate, or brown color, controlled by two different mutations of gene Black (B): brown mutation (b) provides dark-brown tint, and brownl (bl) mutation - light brown. Both colors are acceptable, if they are "rich and warm".
The lilac color of solid-colored Persians is described as having "a rich, warm, pale-lilac with a pink tint" hair color; the tip of nose and pads should be pink. Lilac-Point should have a "white with a frosty coating" color with no darkening, spots - "gray with frosty coating and pinkish tint"; a tip of nose and pads are coral pink. The last is a very delicate and is hard to percept. One needs an appropriate illumination to note an adorable pinkish tint. "But when you see this tint in the rays of sun you are really amazed!" - B. Fox exclaims.
Chocolate gene brown, or b (as well as a dilute gene, or d, controlling for a blue coloring) is recessive. It displays itself when is double-dosed (bb), that is passed from both parents.. Considering a recessive character of genes of rare colorings and turning to Persian color-Points, B. Fox writes: "Everybody knows that Himalayan cats have the many recessive genes: longhair is recessive to shorthair, color with spots - towards even color. And now if one to add here the recessive lilac and chocolate genes he will understand how difficult is to grow a real grand-champion of such color and how long and laborious is this work".
It's impossible to get a lilac or chocolate phenotype if only one of parents carries the combination of genes of this color. The presence of the gene in both parents is obligatory condition for a chocolate colored litter. If only one of parents has a chocolate gene, then the offspring will merely be carriers of this gene and won't have this marvelous color.
Harder task is to receive a lilac-colored cat. Lilac is a chocolate that carries another double set of a dilute (dd) gene, controlling for a blue coloring.
Hence, both parents must possess both genes of chocolate and blue color. If one is to get a lilac cat, he should mate a blue female, carrying a chocolate gene, and a chocolate male, carrying a "blue" gene, and vice versa. At that, only one of four kittens on average will have a desirable lilac color, in the case of bbdd combination (that means that there may not be a lilac kitten in a given litter at all). The same may result from a mating of two blue animals, carrying a chocolate gene, for instance, mating of brother and sister, born from a blue female and chocolate male.
Unfortunately, because pale-colored seal-Points, especially young ones, occur often many "false" chocolate-Points have been registered that are not appear to be real genetically. Sometimes this can be explained by a deep desire of a folder to have and exhibit an animal of a rare color. This results in a big mishmash, wrong pedigrees, involuntary deceptions of customers and following disappointments. How to distinguish a chocolate-Point form a seal-Point? A chocolate-Point has an "incomplete mask", as if it's not fully developed: color of muzzle and ears don't merge together as in seal-Point. The hair on the trunk should be paler, than in a seal-Point, and limbs should be chocolate. If the coloring is correct than the hair color turns from white into chocolate smoothly. Pads should be pink and on no account dark.
About the cholocate gene carriers
As a whole, chocolate-Points differ remarkably from seal-Points by a more light color of body - they don't get dark (or get dark not to that extent) as seal-Points when grow old. This makes their color more contrasting and more striking, then in seal-Points. Lilac-Points also have a white color of body that never turns gray with the time as in the case of many blue-Points. In connection with a peculiar feature of a chocolate gene to "decolorize" the background color of body, digressing from the B. Fox's article we want give some additional information for holders. It concerns Himalayas - chocolate gene carriers, that is animals with Bbcscs genotype.
First of all, let's turn to an acknowledged authority on genetics and cat colors, R.Ribson: "The locus of brown color is represented by two mutant alleles, denoted as b - brown - and bl - light-brown. Heterozygosity by these two alleles causes considerable reduction of color intensity of granules in comparison with norm" (C. O'Bryan, Z. Robinson et all, Cat genetics. Novosybirssk: "Nayka", 1993, c.47-48). What does this really mean?
A pair of cscs genes controls for a Himalayan (color-Point) phenotype. Considering the recession of a chocolate gene b (or bl), pigment in chocolate gene carriers (Bbcscs) is formed in concordance with the presence of a dominant gene B, that is, black, not brown. Hence, this gives a seal-point. However this is a, so-called, incomplete dominance. As a result, an animal with this color carrying the recessive chocolate gene b is slightly paler than a typical seal-point with BBcscs genotype. This makes them very attractive for holders who breed lilacs and chocolates, and exhibition-fanciers cosiness-lovers as well. As noted above, the main drawback of many seal-points is darkening of hair when they grow up. The color doesn't become contrasting but with a dark-brown mask on the light-brown background, or just brown. The hair of the chocolate gene carriers stays paler, as a rule, and, thus, the contrast of a seal-point color remains.
The same should be said about the chocolate gene carriers, "dilute", blue ones that have Bbcscsdd genotype. Blue-point animals with this phenotype have more light nearly white body, mask stays blue and sometimes with a lilac tint. Often these animals are called carriers of a lilac gene, though it's not correct genetically: such a single gene doesn't exist, and the lilac phenotype (lilac-point) is determined by a combination of two couples of chocolate and "blue" (dilute) genes. A lilac-point cat in fact is a blue-point cat with a couple of chocolate genes. Blue-point cat with a single chocolate gene has a blue-point color improved by a dilution of a gray background of body.
The author of this article should note some more conditions that make breeding of rare colorings so difficult and that require a certain level of professionalism. The definite color displays itself only in mature cats; this specially concerns such rare colors as chocolate and lilac. These rare colors finally develop only by 13-15 months. Holders often miss cat-shows in order to allow a cat to improve its type and color. Meanwhile by this time or even earlier a cat needs mating. IF one to consider the necessity of a strict culling during inbreeding he would understand, why the breeding of cats of rare colors takes so much time. Many good holders are unable to stand such difficulties and step aside. Everybody who breeds cats knows that good cats don't appear at one's wish. Years of hard work, losses and disappointments - this is the only way to raise animals of a show quality, especially those that have such rare colors as chocolate and lilac.
B. Fox finishes with the following: "Often holders can hear: What a wonderful color! How I wish to have a chocolate or a lilac cat! But very few of potential customers know: one needs more than 10 years to raise such cat of show quality. Holders who work with rare coloring have to keep kittens longer, than usual, because they show their color and type later. Moreover, kittens can't raise their paws and say which one carries a latent chocolate or lilac gene. Breeding is the only way to learn if the kitten is the gene carrier or not".
Translated by Tatiana Karpova /Moscow/, MSU, Biology faculty, Dep. zoology and ecology