The Genetics of Ragdoll, the colour and the variety

All the various colors and designs of mammalian fur are determined by certain genes that decide pigmentation and therefore appearance. The hair, exactly as the skin is colored thanks to particular molecules called pigments, the greater their concentration, the darker the color.

The colorpoint gene produces a rather bizarre effect on the cat’s fur, the pigment is not fixed evenly over the entire fur but concentrates in the colder areas of the body, tail muzzle and ears, thus creating the “Siamese” effect.

Bonbon’s Kitty Dakota born in our cattery 18/05/2018
female seal color point
in our heart ever now she live with a beautisul family in italy near city of Alessandria

The colorpoint gene, also called Himalayan due to its origin, thanks to the non-uniform pigmentation, allows to heat the cold areas of the body (snout, tail, legs) and to guarantee, due to the candid back, an excellent mimetic effect in the snow. Also being the thermosensitive coloring the color of the coat changes according to the season, in winter the color becomes much more intense while in the summer it goes to clear. Over the years, the color of the hair tends to become fixed, in fact older cats are often visibly darker than young ones.
Another effect of this gene is the color of the eyes, all the colorpoint motif cats have them strictly blue.

A colorpoint kitten is recognized from birth, it is in fact completely white but already in the first hours of life it begins to darken. Ragdoll comes in three varieties: colorpoint, mitted and two-colored, ie three possible designs of the coat. These designs can be in various colors (seal blue chocolate lilac cream red and the variants linx and tortie), the combination of variety and colors therefore describes what the appearance of the cat will be.

The three varieties, recognized as breed standards by feline associations, actually correspond to 6 different genotypes (ie 6 different possible genetic combinations). This anomaly derives from the fact that four different genetic types are included in the “two-colored” variety; all this happens because the aspect (phenotype) of the 4 types of bicolour is similar, however their genetic heritage is profoundly different and behaves differently in the various couplings.

The bicolor variety exists in many cat breeds, but only in the ragdoll is symmetry and balance between white parts and colored parts required.

Genetics

The varieties of the ragdoll are determined by the presence (or absence in the case of the colorpoint) of white partitions in the cat’s mantle. It should be emphasized that ragdoll is the only breed for which there are precise and very strict provisions for white for the varieties.genetics
To better understand the characteristics of the breed it is necessary to refer to some genetics nozones, so as not to bore you too much we have summarized them. The genome is the set of genetic information that characterizes an individual and is composed of several
thousands of genes.
A gene is a segment of DNA that determines an inherited character and occupies one on the chromosome
position called locus. In the cat, following recent studies, it is estimated that there are over 20,000.
Diploid organisms such as humans and cats have two copies of each chromosome
(homologous chromosomes), except for the two sex chromosomes which, in the case of sex individuals
masculine, they are different (X, Y). The cat has a total of 19 chromosomal pairs.
The Alleles are the different alternative forms of the same gene: in an individual the two alleles occupy sui
homologous chromosomes the same locus.
A monofactorial character is controlled by a single gene; therefore its expression depends on which gods
several possible alleles are present in the two homologous chromosms.
A multifactorial character is, instead, influenced by several loci and / or other elements (including environmental).
The genotype of an individual is given by its genetic makeup, it is what is “written” in the DNA contained in the
core of all its cells and is therefore immutable.
The phenotype, instead, is the set of characters that the individual manifests: it depends on his genotype, on the
interactions between genes and even external factors can therefore vary.
Cats being diploid, they have two alleles for each gene that may or may not be identical. In
first case the individual is called homozygous, in the second case he is heterozygous.
To determine the phenotype that will follow a given genotype it is necessary to take into account the dominance of the
alleles.
A dominant allele (expressed with a capital letter of the alphabet) occurs both in homozygous individuals
than in those heterozygous: it is sufficient to possess only one copy to express it.
A recessive allele (described in lower case) occurs only in individuals homozygous for the in allele
question.
In some cases, heterozygotes manifest phenotypically both alleles they possess: it does not happen,
as usual, that one (the dominant one) “covers” the expression of the other (the recessive one) but the two variety we must necessarily face the characteristic that, perhaps more than colors, characterizes the various Ragdolls: the pattern (design of the coat).


Basic color combinations

The color in the Ragdoll is multifactorial, that is determined by more genes in combination: the gene responsible for pigmentation in the Ragdoll has two possible alleles: “B” = black, alternative to “b” = brown (or chocolate), as well as the gene “D” = density, alternative to the allele “d” = dilution. In the presence of “D” (D, D – D, d) the colors Seal (B, B – B, b) and Chocolate (b, b) can occur. Instead, in the presence of “d” in homozygosity (d, d) the colors that can manifest are Blue (B, B – B, b) and Lilac (b, b).


Red color combinations

The possible presence of the “O” = Orange gene causes the red color to manifest, which deserves a more in-depth explanation: the gene in question is “X-linked”, as already mentioned linked only to the X chromosome, then in the male (X , Y) if it is present (XO, Y) it shows the Red color, which completely masks the base color (Seal or Chocolate) and takes on the Cream color in the presence of dilution (d, d) masking the Blue or the Lilac.

In the female, however, having two X chromosomes, the same thing happens only if “O” is present in homozygosity (O, O), otherwise (O, o) the Red (or Cream in the presence of dilution) occurs together with the base color arranging itself in a completely casual manner and giving rise to a mottling called “tortoise scale” or “tortie”.
In very rare cases this can occur in males suffering from genetic syndromes with chromosomal anomalies (X, X, Y) which are however sterile. Nothing clearly happens with “o” in homozygosity (o, o).

To sum up, then, the colors of Ragdoll are four basic (Seal, Chocolate, Blue, Lilac), plus Rosso and Crema, and four possible combinations of Tortie (Seal-Rosso, Chocolate-Rosso, Blue-Crema, Lilac-Crema) .


Lynching combinations

But it does not end here, since the possible presence of Agoutì (A, A – A, a) determines the manifestation of “lynching” (called Lynx or Tabby) which adapts to each of the colors described above.


Pattern combinations

Ragdoll is presented in three varieties (Colorpoint, Mitted, Bicolor) which manifest themselves on the basis of the combination of the alleles of the gene responsible for the distribution of white spots (White Spotting which is different from the white “W” gene responsible for the completely white coat not albino) described with the letters s, sm, S.

The Colorpoint variety without special white patterns manifests as “s” in homozygosity (s, s); the Mitted (front gloves and white back socks) manifests itself with the combination of the surname “s, sm” while the Bicolor, which presents a sort of “V” upside down on the face and white legs, manifests itself with different genotypic combinations: ” sm, sm ”(defined High-Mitted),“ S, s ”(True Bicolor),“ S, sm ”(Mid-High-White) and“ S, S ”(High White or Van).
(see table 3 – pattern)

Considering the six colors (plus the four Tortie combinations), the three patterns and the Agoutì, you get as many as 36 different varieties for males and even 60 for females!