Rabbit Color Genetics

From the fiery blaze of an orange blond to the inky darkness of sable black, rabbit coats come in a kaleidoscope of colors. But what hidden genetics produce this rainbow of fur? Delve into the pigments, patterns, and gene combinations that create lavish lilacs, rich chocolates, shimmering Himalayans, and more. Learn how short-haired breeds showcase saturated hues while angoras diffuse colors into pastel palettes. See how nature gifts wild rabbits with cryptic camouflage fur. Whether you’re a breeder designing new strains or just rabbit-crazy, this is your guide to the genetics of rabbit colors.

Basic Color Genes

Rabbit fur color is determined by a series of genes that code for different pigments and patterns. The main pigments that contribute to rabbit coat color are eumelanin (black/brown) and pheomelanin (red/yellow). The distribution of these pigments is controlled by color pattern genes. Some of the basic color genes in rabbits include:

Agouti: The agouti gene (A) codes for black-tipped hairs alternating with yellow bands. This results in an agouti pattern seen in wild rabbits and agouti domestic breeds. The recessive non-agouti gene (a) allows for solid color.

Albino: The albino gene (c) prevents any pigment from being produced, resulting in a white rabbit with pink eyes. The recessive full color gene (C) allows for normal pigment production.

Brown: The brown gene (b) converts black pigment to brown. Rabbits with the recessive black gene (B) will have black pigment.

Dilution: The dilution gene (d) dilutes black pigment to blue/gray. Rabbits with the recessive full color gene (D) will have normal intensity black pigment.

Silver: The silver gene (si) lightens black/brown fur to silver. The recessive normal gene (Si) allows for full coloration.

Over 100 different genes have been identified that control some aspect of rabbit coat color. The combination and interaction between these genes produces the wide variety of colors and patterns seen in domestic rabbit breeds.

Typical Rabbit Pigments

There are two main pigments that contribute to rabbit fur colors:

Eumelanin – This pigment produces black and brown colors. The genetics of the rabbit controls whether eumelanin is deposited as pure black, or converted to brown through the action of the brown (b) gene. The intensity of black/brown eumelanin is also influenced by dilute genes.

Pheomelanin – This pigment produces red and yellow colors. It is responsible for the orange/reddish tones in agouti patterned rabbits, as well as red eyed whites. The genetics of the rabbit controls the intensity and distribution of pheomelanin.

In addition to these two main pigments, there are several other factors that influence the final coat color:

-Density of pigment granules in the hair shaft

-Distribution of pigment within each hair

-Interaction between eumelanin and pheomelanin

-Presence of intermediate pigments

-Surface reflection effects

This complex interplay between multiple pigments and genetic factors allows for the incredible diversity of colors and patterns seen among domestic rabbit breeds.

Long and Short Hair Colors

There are over 50 domestic rabbit breeds that exhibit a wide range of fur lengths. From the extra short velvet-like fur of the Rex breeds to the long angora locks of the Angora breed, fur length is an important aspect of rabbit coat genetics.

Short Hair Breeds:

In short hair breeds like the Netherland Dwarf and Mini Rex, colors appear more saturated and vivid. With less hair length, more of the pigmented portions of the hair shafts are exposed. These breeds exhibit bright pure colors like jet black and rich ruby red.

Common colors seen in short hair breeds include black, blue, chocolate, lilac, red, orange, tortoiseshell, opal, and agouti patterns. Dilute colors and color patterns may appear muted in short hair. Point coloration is rare, as less fur length is available to create dramatic contrast.

Long Hair Breeds:

Long haired angora breeds like the English, French, Giant, and Satin Angora have fur lengths up to 6 inches. This extra length creates a diffusing effect, softening and lightening color hues. Darker colors appear lighter, while dilute colors seem brighter and more saturated.

Long hair allows for the expression of subtle color gradations like tortoiseshell and lynx patterns. It also enables the development of point coloration, seen in Himalayan marked breeds. The fur length highlights contrast between the darker points and lighter body.

Wild Rabbit Colors

Wild rabbits across the world exhibit a range of natural coat colors that provide camouflage in their native habitats. These agouti patterns are the result of modified eumelanin and pheomelanin pigments controlled by genetics.

Cottontail Rabbits:

The common North American cottontail rabbit has fur that is grayish brown to reddish brown. Individual hairs are ticked with black, gray and brown in an agouti banding pattern. The underbelly is white. This provides camouflage against dirt and vegetation.

European Rabbits:

European wild rabbits are typically grayish brown with a light belly. But pigment-producing genes can create other color variations like black, brown, reddish, or white coats. The leucistic allele produces cream or tan rabbits.

Volcano Rabbits:

The rare volcano rabbit of Mexico has fur that is blackish-gray ticked with brown and yellow bands. Their agouti hairs closely match the dark volcanic rock of their habitat.

Amami Rabbit:

Native to Japan, the Amami rabbit has coarse black-and-white banding over a brownish-gray coat. This disruptive patterning helps conceal them in brushy undergrowth.

Color Gene Groups

There are thousands of possible genetic combinations that produce unique rabbit coat colors. However, these varied colors are created through a few major gene groups including:

Pigment genes – Control presence/absence and density of eumelanin and pheomelanin

Pattern genes – Control distribution of pigment colors on hair shaft

Modifier genes – Alter other color genes' effects

Dilution genes – Lighten intensity of normal pigment

Point genes – Produce Himalayan pattern

Marking genes – Create spotted/broken patterns

While individually these color genes control just one aspect of rabbit fur, combining genes from the various groups allows breeders to develop new colors and patterns.

Color Pattern Groups

There are several distinct color pattern gene groups in rabbits that control pigment distribution in the fur:

1. Self

The self pattern gene (aa) produces solid colored fur without banding or markings. It is recessive to the agouti gene. Self colors include black, blue, chocolate, lilac, red, and beige. Shading may occur across the body.

Examples: Himalayan, Cinnamon

2. Agouti

The agouti pattern gene (A_) produces hairs banded with eumelanin (black/brown) and pheomelanin (yellow/red) pigment. It is dominant over self. Agouti creates a salt-and-pepper ticking appearance.

Examples: Cottontail rabbit, English Spot

3. Tan

The tan pattern gene restricts pheomelanin pigment to certain body areas like the ears, nose, feet, and tail. The rest of the body exhibits diluted black, blue, or chocolate self color.

Examples: Tan rabbit, Rhinelander

The Albino Color Gene

The recessive allele at the 'C' locus is known as the albino gene (cc). This gene prevents the formation of pigment in skin, fur, and eyes. Rabbits that inherit two copies of the albino allele are completely lacking in pigment and appear white with pink eyes. They are often referred to as 'albino' rabbits.

The albino gene inhibits the production and distribution of both eumelanin and pheomelanin. Without these pigments, the fur lacks any coloration and appears white. The lack of pigment in the eyes causes the blood vessels to show through, resulting in a pinkish eye color.

While rare, true albino rabbits can occur both in wild and domestic populations. However, most pure white domestic rabbits with pink eyes are not albinos, but rather white spotting breeds such as Himalayans and Dutch rabbits.

REWs (Ruby-Eyed Whites)

The REW coloration refers to a rabbit that has pure white fur and bright ruby-red eyes. Despite the striking eye color, REW rabbits are not true albinos. They have pigment restricted to just the eye area.

REW coloration is produced by a combination of recessive genes:

Pink-eyed white spotting gene (en) which limits pigment to the eyes
Ruby-eyed gene (ru) which produces red eye color
Non-agouti (a) which gives solid white fur

Breeds like Checkered Giants, English Spots, Palominos, and Californians can display the REW pattern. It is frequently seen in laboratory-raised rabbits as well. The white coats with ruby eyes make a very attractive color combination.

BEWs (Blue-Eyed Whites)

Similar in appearance to REWs, BEW rabbits have pure white coats coupled with deep blue-gray eyes. This coloration is produced by a pair of recessive genes:

The Vienna white (v) gene which prevents pigment cell migration and manifestation of color.
The blue eyed white (bew) gene which dilutes eye pigment leading to blue-gray eyes.

BEW is the color requirement of the Vienna breed. When Vienna carriers are crossed with other breeds, the resulting offspring can also inherit BEW coloring. The striking white and blue-eyed pattern is popular for breeding programs and showing.

References:

https://rabbitbreeders.us/questions-and-answers/rabbit-color-genetics/
https://www.onlinerabbitcare.com/questions-and-answers/rabbit-color-genetics/