Rabbit Coat Color Genetics
Author: Sarah Giers
Genetics are what make a rabbit, or any living organism, look
the way it does. It makes a rabbit be a certain size, be a
certain color, have a certain type of coat or ears, and more.
This introduction, however, is just for the genetics concerning
the coat colors of rabbits. Chromosomes and Genes
Chromosomes are strands of DNA that act as a map. They map out
exactly how the rabbit will look. In each cell, not including
the sex cells and red blood cells, a rabbit has 22 chromosomes.
Each one of these pairs controls a different thing about the
rabbit. For example, one might control the rabbits gender, some
control color, others control fur. Each chromosome pair has two
genes in it. These genes may be the same, or they might be
different, but there are always two (unless there is a genetic
mutation, but we will not discuss that here). For example, a
rabbit might have two genes for blue eyes. Conversely, a rabbit
might have one gene for red eyes, and one gene for brown eyes.
If a rabbit has two of the same type of genes in a certain
chromosome pair, it is referred to as being homozygous for that
particular gene. If it has two different genes in a certain
chromosome pair, it is referred to as being heterozygous.
If a rabbit is heterozygous, one of the genes is usually
stronger than the other. That means that the stronger gene will
be the one to cause the effect n the rabbit, and the weaker one
will just hide, though it can still be passed on to the rabbit's
offspring. Stronger genes are referred to as being dominant, and
weaker genes are called recessive. For example, if a rabbit had
one gene for red eyes and one gene for brown eyes, the rabbit
would have brown eyes because the gene for brown eyes is
dominant to the gene for red eyes. For a rabbit to have red
eyes, it would have to be homozygous for red eyes, since the
gene for red eyes is the most recessive.
Sometimes certain genes are not really stronger or weaker than
another. These genes are referred to as being incompletely
dominant to each other. This means if two different genes that
were incompletely dominant to each other were in the same
rabbit, the rabbit would have traits from both genes. In
flowers, and example of an incompletely dominant gene can be
found when you breed a white flower and a red flower and you get
a pink flower.
Color Genes
Each variety of rabbits requires many genes in order to look the
way they look. Certain genes are related, and they are all found
on the same are of the DNA strand. These groups of genes are
called loci, or locus if it is just one.
You may have seen some genetics stuff written with a bunch of
ABC's and other letters. Well, those are how various loci and
genes are written. Genes have their own alphabet. When the
"letters" of the genetics alphabet are all put together, it is
referred to as the rabbit's genotype. This is basically a list
of all the color genes that rabbit has, or at least the ones
that are important to understanding that particular variety.
A LOCUS
The first "letter" in the genetics alphabet is "A." This
determines the basic pattern of the rabbit. The genes are as
follows:
A: Agouti Pattern - These rabbits have tan, white, or fawn
markings on the belly, underside of the tail, inside of the feet
and legs, inside the ears and nostrils, around the eyes, and in
the shape of a triangle at the nape of the neck. On the body,
the fur has rings of different colors when you blow into the
coat.
a(t): Tan Pattern - Like agouti pattern, these rabbits have tan,
white, or fawn markings on the belly, underside of the tail,
inside of the feet and legs, inside the ears and nostrils,
around the eyes, and in the shape of a triangle at the nape of
the neck. However, the body does not have the different color
rings when you blow into the coat.
a: Self Pattern - Each hair is a solid color, and there are no
tan, white, or fawn markings.
B LOCUS
"B" is the next "letter". This "letter" tells the rabbit how
intense the color of the fur is. The genes are as follows:
B: Black - The rabbit is black based, meaning the base color is
black or blue.
b: Brown - The rabbit is brown based, meaning the base color is
chocolate or lilac.
C LOCUS
"C" is the next "letter". This "letter" tells the rabbit whether
or not to have red coloring, as well as how deep and dark the
base coloring is. The genes are as follows:
C: Full Color - The red coloration of the fur is full
expressed, and the base coloring is also fully expressed.
c(chd): Chinchilla Dark - All red coloration is removed from
the coat, but the base coloring is still fully expressed.
c(chl): Chinchilla Light - All red coloration is removed from
the coat, and the base coloring is lightened, causing darker
shading around the head, ears, tail, feet, and legs.
c(h): Californian - All red coloration is removed, and the base
coloration is restricted to the nose, ears, feet, legs, and
tail. The eyes are red.
c: Albino - All color is restricted, leaving a pure white
rabbit with red eyes.
D LOCUS
Next in the genetics alphabet is "D". This "letter" determines
how much pigment is in each hair shaft. The less pigment there
is, the lighter the color is. The genes are as follows:
D: Dense - Full amount of pigment
d: Dilute - The pigment is less, causing the color to look
diluted.
E LOCUS
The "letter" "E" controls the banding, or color rings (remember
in agoutis where you can see the rings when you blow into the
coat?) of a rabbit. The genes are as follows:
E(s): Steel - The under color is extended and "takes over" the
color, leaving a mostly solid colored rabbit with some gold or
silver tipped hairs.
E: Full-Extension - The rabbit has normal color, and the bands
are not disturbed.
e(j): Japanese - This takes the bands and actually separates the
band color into different hair shafts. This is how Tricolor
and Harlequin are produced.
e: Non-Extension - There is no color extension, leaving only
what would be the intermediate band in a normal colored rabbit.
This is how Oranges, Frosed Pearls, and Tortoises are produced.
EN LOCUS
The "En" "letter" controls a different type of pattern. The
genes are as follows:
En English Spotting - The rabbit is white with colored spots.
en: Solid - The rabbit has no spots.
V LOCUS
"V" is the next "letter" in the genetic alphabet, and for most
breeds, no more of the alphabet is needed to know the variety.
This tells whether or not the rabbit is a Blue Eyed White.
V: Non-Vienna - Normal colored rabbit.
v: Vienna - Blue Eyed White.
W LOCUS
This "letter" is rarely included in the genotype because it is
not very important in most varieties, though all varieties DO
use it.
W: Non-Wideband - Normal coloring.
w: Wideband - The red color becomes very intense, the
intermediate band widens, and the red color "takes over" all
tan pattern and agouti markings so that instead of being cream
or white, they are red.
SI LOCUS
This "letter" is another that is rarely included in the
genotype. All non-silver rabbits do not need this included in
their genotype in order to let the viewer know that the rabbit
is not silver.
Si: No-Silver - Normal coloring.
si: Silver - Silver-white hairs are scattered throughout the
normal coloring.
DU LOCUS
This "letter" is usually only used when referring to the breeds
Dutch, Dwarf Hotot, and Hotot.
Du: Non-Dutch - Normal coloring.
du(d): Dutch Dark - Dutch markings, mostly colored rather than
white.
du(w): Dutch White - Dutch markings, mostly white rather than
colored.
Genotypes
In order to have a full knowledge of the variety of a rabbit,
just by looking at the genotype, a full genotype, using all of
these loci. For example, a Chestnut Agouti would be denoted as
A_ B_ C_ D_ E_ enen V_ W_ Si_ Du_. The spaces just mean that a
recessive gene could be there, hidden by the dominant gene.
However, most people know that the shortened form of the
genotype, A_ B_ C_ D_ E_ enen, also means Chestnut Agouti.
See Also:
Index of All Rabbit Care & Bunny
Fun Stuff
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