KosmikCattery - Coat Color Gene(s)

Felines Black Gene(s)

The genetics of coat color in cats is quite complex and involves multiple genes. However, for the purpose of our discussion on black coats, we'll focus primarily on the B locus (Black locus).

1. The B locus (Black locus):

Dominant B allele results in a black coat color.
Recessive b allele leads to a chocolate or brown color.
Another recessive form bl results in a cinnamon color.

To explain:

BB or Bb: A cat with either of these genotypes will have a black coat.
bb: A cat with this genotype will have a chocolate or brown coat.
bbl: A cat with this genotype will have a cinnamon coat.

It's worth noting that the actual expression of these colors can be modified or hidden by other genes.

2. Extension (or E locus):

Another gene of interest when discussing black coats is the E locus. This gene controls whether black pigment (eumelanin) appears throughout the coat or is restricted to certain points.

EE or Ee: Allows black pigment to be displayed throughout the coat.
ee: Restricts black pigment to the points (ears, face, paws, tail) and results in a Siamese or Himalayan appearance.

In the presence of the ee genotype, even if the cat has genes for a black coat, it will display a pointed pattern, with a cream body and darker points.

3. Dilution (or D locus):

The D locus controls the dilution of color. When the dilution gene is present, it lightens the coat color.

DD or Dd: Full color (no dilution)
dd: Diluted color. In black cats, this results in a blue or grayish coat.

4. White and White Spotting:

Two more factors can interfere with the appearance of a black coat:

Complete white (W locus): Dominant and can override all other color genes. A cat with this gene will be completely white, regardless of its genetic coat color.
White spotting (S locus): This gene can cause varying amounts of white patches on a cat, which can range from a small locket or mittens to almost entirely white.

5. Agouti (or A locus):

The Agouti gene affects the pattern of the coat, specifically whether the individual hairs have bands of color (tabby pattern) or not.

AA or Aa: Produces a tabby pattern. Even if the cat has genes for a black coat, this gene can cause the cat to appear as a black tabby.
aa: The coat will not have a tabby pattern. With black genes, the cat will appear solid black.

However, it should be noted that the visibility of the tabby pattern can vary widely and may be masked or barely visible in some cats.

In conclusion, while the B locus is central in determining a cat's black coat, the expression of that black coat can be influenced by a number of other genetic factors. This is just a snapshot of the intricate and fascinating world of feline genetics!

Felines White Gene(s)

The term "White gene" in felines usually refers to the gene responsible for the complete white coat seen in some cats. This gene masks any other color the cat might genetically be, resulting in an all-white appearance.

Here's a basic overview:

Gene Symbol and Locus: The white gene is typically symbolized by the letter "W". The dominant form (which causes the white coat) is "W", and the non-dominant or recessive form is "w".
Dominance: The "W" allele is dominant. This means that only one copy needs to be present for the cat to be white. Therefore, cats with the genotypes "WW" or "Ww" will be white, whereas only "ww" cats will show their underlying coat color.
Epistasis: The action of the white gene is epistatic to other color genes. This means it can mask or override the effects of other genes that determine coat color. A white cat could genetically be black, tabby, calico, etc., but you won't see these colors because the white gene masks them.
Blue Eyes and Deafness: One intriguing aspect of white cats, especially those with blue eyes, is the association with deafness. A white cat with one blue eye might be deaf in the ear on the same side as the blue eye. A cat with two blue eyes could be deaf in both ears. However, not all blue-eyed white cats are deaf. This deafness is due to the absence of a necessary layer of cells in the inner ear, which is a side effect of the genetic pathway that leads to white coat and blue eyes.
Relation to White Spotting: It's essential to differentiate between the white gene (W) and the white spotting genes (S). The white spotting genes result in patterns like tuxedo, mittens, or the classic "cow" spots on cats, whereas the white gene results in a completely white cat.

It's fascinating how genetics can influence not just the appearance but also other aspects of physiology and health in animals. If you're breeding cats or thinking about it, it's always a good idea to understand the potential genetic implications of pairing certain individuals.

Dominant White (W gene)
- W allele: This dominant allele masks any other coat color and pattern, resulting in an entirely white cat. Cats possessing one (Ww) or two (WW Homozygous) copies will appear white. The mechanism here involves mutation of the KIT gene.
- w allele: The recessive form does not affect coat color. Heterozygous (Ww): Cats with one dominant white allele and one non-white allele. These cats might be deaf in one ear, particularly if they have one blue eye and one of another color.
White Spotting (S gene)
- White spotting is different from the dominant white. It results in various amounts of white on the cat, ranging from a small locket or mittens to almost entirely white (but not completely white like the W allele).
- SS or Ss: These genotypes typically produce cats with more significant amounts of white spotting (like tuxedos, bicolors, or even "van" patterns with color mainly on the head and tail).
- ss: These cats will show no or minimal white.
Albinism (C gene)
- This is another gene series that affects pigmentation in cats.
- C: Full color
- cb: Burmese (sepia) coloration, which is a dilution.
- cs: Siamese (pointed) coloration. Only the extremities show color, and the body is a lighter shade.
- c: True albino, which is rare.

While the Dominant White (W) is the primary gene often referred to as the "white gene" in cats, the above-mentioned genes also play roles in the expression of white or reduced pigmentation in cats. It's worth noting that the genetics of coat color in cats (and animals in general) can be quite complex and involve various interactions among multiple genes.

Blue Eyes: The presence of blue eyes in white cats is not exclusively determined by the W gene. While the W gene can cause a cat to have blue eyes, not all white cats with the W gene will have blue eyes. Similarly, a cat can have blue eyes without being white or having the W gene.
Piebald or White Spotting (S): While this gene is responsible for white patches on a cat rather than a completely white coat, it's worth mentioning because it can sometimes be confused with the dominant white gene. Cats with the piebald gene can have varying degrees of white in their coat, from minimal white spotting to almost entirely white. This gene is not directly responsible for blue eyes, but cats with large amounts of white spotting can occasionally have blue eyes.

The genetics of coat color and eye color in cats is intricate, and several genes can influence the final appearance. It's also worth noting that while there's a known association between white coat color, blue eyes, and deafness in cats, it doesn't mean that every white cat with blue eyes will be deaf. Always consult with a veterinarian or a cat geneticist for more specific information about an individual cat's genetics.

Feline Black Gene(s)

Feline coat color genetics is a complex field with various genes influencing a cat's coat color and pattern. One of the more interesting and prominent genes in the context of coat color is the "Black" gene. This gene, often represented by the symbol "B," dictates whether a cat's coat is black or chocolate and has three primary allelic variants:

B (Black): This allele is dominant over the others and leads to the production of a black pigment called eumelanin. Cats with the genotype BB or Bb will have black fur.
b (Chocolate): This is a recessive allele. A cat will only display a chocolate coat color when it has two copies of this allele (bb). When combined with the Black allele (Bb), the dominant Black will mask the chocolate, resulting in a black-coated cat.
bl (Cinnamon): This is another recessive allele. To show a cinnamon coat color, a cat must have two copies of this allele (blbl). If combined with the Chocolate allele (bbl), the chocolate color will be dominant, masking the cinnamon and the cat will be chocolate-colored. If combined with the Black allele (Bbl), the dominant Black will mask both the cinnamon and chocolate, resulting in a black-coated cat.

It's worth noting that these are just the basics. Other genes can further modify or influence these colors. For instance, the Dilution gene can affect the intensity of these colors, turning black into blue (a kind of gray), chocolate into lilac, and cinnamon into fawn.

Solid Gene(s) & how they work

B locus (Black/Brown): Determines whether the cat's eumelanin (dark pigment) will be black or brown.
- B allele: Black coat.
- b allele: Chocolate coat.
- b<sup>s</sup> allele: Cinnamon coat.
- The B allele is dominant over the b and b<sup>s</sup> alleles.
D locus (Dilution): Affects the density of the pigment, diluting the primary colors.
- D allele: Dense, normal color (e.g., black, chocolate, or cinnamon based on the B locus).
- d allele: Diluted color (e.g., blue for black, lilac for chocolate, and fawn for cinnamon).
- The D allele is dominant over the d allele.
O locus (Orange/Non-orange): Determines the presence of the orange/red pigment, phaeomelanin. This gene is located on the X chromosome, which makes the inheritance of the orange coloration sex-linked.
- O allele: Produces orange pigment.
- o allele: Does not produce orange pigment.
- Males (XY) can be either orange (OY) or non-orange (oY). Females (XX) can be orange (OO), tortoiseshell/calico (Oo), or non-orange (oo).
A locus (Agouti): This is a gene that determines whether a cat will have banded hairs (agouti) or solid color hairs (non-agouti). The presence of the agouti gene causes hairs to have multiple colors along their length, resulting in the typical tabby pattern.
- A allele: Allows for the expression of the tabby pattern.
- a allele: Non-agouti or solid color.
- The A allele is dominant over the a allele.

To have a solid colored cat, the primary gene to consider is the A locus. Cats with the aa genotype will have a solid color, though the specific color will be determined by the interaction of the other genes mentioned above.

It's important to note that while the A locus determines the solid versus tabby pattern, other genes (like white spotting genes) can overlay these base patterns, adding even more complexity to feline coat genetics.

Feline Tabby Gene(s)

The term "tabby" when referring to cats doesn't point to a breed, but rather to a coat pattern. The genes responsible for the tabby pattern are found in all domestic cats. In fact, if you look closely at many solid-colored cats, you might see faint tabby patterns, especially when they are kittens.

There are several distinct tabby patterns, and they are influenced by multiple genes. Here's a detailed breakdown:

Tabby Gene (Agouti) [A/a]
- The primary gene responsible for the tabby pattern is the Agouti gene.
- Cats that possess the dominant allele (A) will show a tabby pattern. If they have the recessive allele (aa), they'll be solid-colored, but as mentioned above, faint tabby markings might be present when they're young or in certain lighting.
Tabby Pattern Genes [Mc/mc]
- The specific pattern of the tabby marking – whether it's mackerel, classic, ticked, or spotted – is determined mainly by the Tabby Pattern gene.
  - Mackerel (Mc): This is the default "wild type" pattern. Cats with this pattern have vertical, thin stripes, often described as a “fishbone” pattern. This gives them a look somewhat reminiscent of a mackerel fish, hence the name.
  - Classic (mc^mc): Cats with two copies of the recessive allele will have a blotched or marbled pattern, often with a butterfly pattern over the shoulders and a bullseye or oyster pattern on the sides.
  - Ticked (Ta): Instead of a widespread pattern across their body, ticked tabbies have individual hairs that are banded with multiple colors. This results in a salt-and-pepper or sand-like appearance. The Abyssinian breed is a prime example of the ticked pattern.
  - Spotted: This pattern is still being studied, but it's believed that spotted tabbies may result from a modifier gene that breaks up the mackerel pattern into spots.
Dense Pigmentation Gene [D/d]
- While not exclusive to tabby patterns, this gene affects the intensity of the color. The dominant form (D) results in dense, deep coloration, while the recessive form (dd) dilutes the color. For instance, black becomes gray, and orange becomes cream.
Orange Gene [O/o]
- This gene affects the color of the tabby pattern. The dominant allele (O) results in an orange or ginger color (often called "red" in cat fancy terms), and its expression overrides both black and agouti. This means all red or cream cats (whether they are male OO or female Oo) will show a tabby pattern, even if it's faint.
- The non-orange allele (o) will result in a black-based color, which can be affected by other genes to result in colors like brown, chocolate, or cinnamon.
Spotting Gene
- Again, not exclusive to tabbies, but this gene can superimpose white spotting on a tabby pattern, which can lead to tabby-and-white cats.

In essence, the tabby pattern in cats is a result of a complex interplay between these genes and possibly others. Each of these genes can combine in various ways to produce the rich diversity of patterns and colors seen in the domestic cat population.

Feline Dilution Gene(s)

Feline Dilution Gene - Basics:

Locus: The gene that governs dilution in cats is often referred to as the "D locus."
Main Alleles: There are two main alleles (gene variants) at the D locus:
- D (non-dilute or dense)
- d (dilute)

A cat with two copies of the "d" allele (dd) will display the dilute version of its base color. A cat with one or two copies of the "D" allele (Dd or DD) will display the dense or non-dilute version of its base color.

Color Transformation Due to Dilution:

Black to Blue: The most commonly known effect of the dilution gene is turning a black cat into a blue (or gray) cat. In the absence of dilution (DD or Dd), the cat will be black, but with two copies of the dilute gene (dd), the cat will be blue.
Chocolate to Lilac: A chocolate (or brown) cat becomes lilac (or lavender) when it has two dilute alleles.
Red to Cream: Red or orange cats (often referred to as ginger or marmalade) become cream when the dilution gene is present.

Other Points:

Uniform Effect: The dilution gene affects the entire coat of the cat, creating a uniform appearance.
Not Albinism: The dilution gene is different from albinism, which is governed by the "C locus" and can completely remove pigment, leading to white cats with pink eyes.
Other Modifiers: There are other genetic modifiers and loci that can influence coat color and patterns in complex ways, so it's essential to recognize that the dilution gene is just one piece of the puzzle.
Dilution Alopecia: Some breeds, like the British Shorthair, which often carry the dilute gene, can be susceptible to a condition called dilution alopecia. It's a type of hair loss specifically associated with dilute-colored coats. The exact cause of dilution alopecia is unclear, but it seems to be more common in blue cats, though it can affect other dilute colors as well.

Inheritance Pattern:

The dilution gene follows a simple Mendelian inheritance pattern:

DD: Non-dilute
Dd: Non-dilute (but carrier of the dilute gene)
dd: Dilute

If two carrier cats (Dd) mate, there's a 25% chance their offspring will be DD (non-dilute), a 50% chance they will be Dd (carrier), and a 25% chance they will be dd (dilute).

Understanding coat color genetics can be fascinating, especially when you begin to layer in other genetic factors like agouti, tabby patterns, white spotting, and more. The dilution gene, however, remains one of the more straightforward and easily observable genetic traits in feline genetics.

Feline Shaded Gene(s)

Basics of Feline Coat Color Genetics:
- The basic color of a cat's coat is determined by a few primary genes. For example, the B/b gene determines whether a cat is black or chocolate, and the O gene determines if a cat is orange (like in calicos or orange tabbies).
- Overlaying these base colors, there are several other genes that modify the distribution and intensity of pigment in individual hairs, resulting in various patterns.
Tipping and the Inhibitor Gene (I/i):
- The term "tipping" refers to the coloration at the tips of the hair shafts.
- The inhibitor gene (I) plays a central role in determining tipping. Cats with an I allele will show some form of tipping, while those with the ii genotype will not.
- The presence of the inhibitor gene (often represented as) causes the hair shaft to have a reduced amount of pigmentation. The extent of this reduced pigmentation depends on other modifying genes.
Chinchilla and Shaded Patterns:
- Chinchilla (Silver) Pattern: When there's a wide band of un-pigmented hair at the base with only the tip showing pigment, it results in the chinchilla pattern. This gives the coat a sparkling silver appearance. Genetically, chinchilla cats are often denoted as having the I gene along with other modifier genes.
- Shaded Pattern: This pattern is characterized by more pigment on the hair shaft compared to chinchilla cats but less than a typical solid-colored cat. Typically, about 1/3 to 1/2 of the hair is pigmented starting from the tip. This results in a "shaded" appearance. The exact genetic combination leading to this phenotype can vary, but it's usually a combination of the I gene with other modifier genes that control the extent of tipping.
Goldens:
- Just like silvers (chinchilla and shaded), golden cats have a similar pattern but on a non-silver background. This results in a warm, golden hue rather than the cool silver.
Other Modifying Factors:
- Wideband Gene: This gene further influences the distribution of color on the hair shaft. It's believed that the presence of this gene causes the pigment to be pushed even further towards the tip of the hair.
- Density and Dilution: Other genes can influence the density of pigment granules and whether colors are "diluted" (like turning black into blue/grey).
Breed Specificity:
- While many breeds can exhibit shaded and chinchilla patterns, they're particularly prominent in breeds like Persians and British Shorthairs.

Genetics can be complex, and while we've gained significant insights into feline genetics, there are still areas that require more research. The above details provide a basic understanding of the shaded and chinchilla patterns in cats.

Breakdown of the felines Agouti Gene(s)

Agouti vs. Non-Agouti Phenotypes:
- Agouti (A): When a cat has the dominant agouti allele (A), the individual hairs show alternating bands of color. This pattern is commonly seen in many wild cats and gives them a "ticked" or "tabby" appearance. Domesticated cats with this phenotype often have a coat that resembles the wildtype pattern with multiple bands of color on each hair. Think of the common brown tabby cat.
- Non-agouti or Solid (a): The recessive form (a) leads to solid color hairs because it prevents the alternating bands of color from forming. When homozygous (aa), this results in a solid colored cat, such as a black or chocolate cat, given that no other color-diluting or pattern genes are at play.
Function at the Molecular Level: The agouti gene produces the agouti signaling protein (ASP). In the presence of ASP, melanocytes (cells that produce pigment) switch from producing black eumelanin to the yellow/red phaeomelanin. This switch results in the banded appearance on hairs. When the agouti gene isn't expressed (as in the aa genotype), the melanocytes only produce the black eumelanin, leading to solid-colored hairs.
Interaction with Other Genes: The actual appearance of an agouti or non-agouti cat can be influenced by other genes. For instance:
- Tabby Patterns: While the agouti gene determines the banded appearance of individual hairs, other genes decide the broader pattern of stripes, spots, or swirls seen in tabby cats.
- Color Dilution: Other genes can dilute the intensity of colors, leading to shades like blue (diluted black) or lilac (diluted chocolate).
- White Patterns and Spots: Yet other genes can introduce white patches, mittens, or even create entirely white cats.
Importance in Nature: The agouti pattern is believed to be an evolutionary adaptation that helps many wild animals, including wildcats, camouflage in their natural habitats. The banded hairs break up the silhouette of the animal, making it harder for predators (or prey) to detect them.
Variation Across Species: While the focus here is on felines, the agouti gene and its effects on coat color can be found in various other mammals, including dogs, horses, and rodents. However, the specific manifestations and nuances of how the gene works can vary between species.

In conclusion, the agouti gene is a pivotal player in the mosaic of genetics that determines feline coat coloration. It's a great example of how one gene can have a pronounced and visually evident impact on an organism's phenotype.