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A Summary of Rabbit Color Code Genetics
Information By - Dr. Katrin Becker
An Illustrated Guide to Rabbit Coat Colour Genetics
Visit Dr. Katrin Becker's Web Site,
Click Here.
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Color Code Summary:
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Fundamental Pigments: Black & Yellow (red)
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All
genes come in pairs. If both genes of a pair are the same,
it is said to be homozygous for that trait.
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Genotype refers to the gene itself, while phenotype
refers to
what we can see. Sometimes a phenotype will imply a certain
combination of genes but the actual genotype is different.
The best way to discover an animal's genotype is through test
breeding with an animal whose genotype is known.
What gives the Rex its remarkable coat?
Rex rabbits have the same double coat as other rabbits, it's just
that their guard hairs are the same length as the undercoat (usually
the outer coat is longer). This has several effects:
The outercoat does not hold the undercoat down and the entire pelt
appears to stand on end. In fact, a coat that lies flat is a fault
in a Rex.
The coat has an amazingly plush feel - these really are velveteen rabbits.
The guard hairs carry the same amount of colour as a regular length
hair but they are considerably shorter. This means that the colour
of the hair appears more intense. Contrast that with long-coated
rabbits like the angora when the same amount of colour is spread out
over a MUCH longer hair; these rabbits always appear to have pale colours.
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Gene Labels:
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There are 5 main groups of color genes, each controlling a different
aspect of the color and markings. The genes within each group are
listed in decreasing order of dominance. A Capital letter denotes a dominant gene.
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PATTERNS [A / at / a ]:
Agouti is the basic "wild" color. Hairs on different parts of the body are
colored differently, but will have three-five different colored
bands on each hair. This pattern looks different on a Rex because of
the shorter hairs. The bands are smaller and the colors appear more
intense.
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A = Agouti ["wild" color; multi-banded hair shaft]
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at = Tan [giving tan or "otter" markings]
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a = Self [solid color]
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COLOR:
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B =
Black
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b =
Chocolate
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SHADING:
[Controls
the amount of pigment in the hair; relative
amounts shown as units
of black 'B' and yellow( or red) 'Y' color.
Imagine
that the total amount of pigment in hair is the same for
all hairs.
As a result, shorter hairs appear darker (and also why
long-haired varieties look faded). This explains the shading pattern found in
seals, sables, torts, and the pointed colors.]
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C = Normal [BBBBYYY]
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cchd = Dark Chinchilla [BBBBY--]
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cchl = Light Chinchilla [ shaded : seal & sable] [BB-----]
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ch = Himalayan [BB-----]
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c = White [Albino : absence of color] [-------]
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DILUTION:
[Controls
the "intensity" of the color:
a diluted black is a blue,
and a diluted brown is a lilac]
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D = Full Strength
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d = Diluted
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EXTENSION:
[Controls the presence, and extent of black on tips
of hair and in
under color]
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Ed
= Dominant
[ not accepted in REX]
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Es
= Steel
[ not accepted in REX; causes the black on the hair to
be extended, often covering the middle band with dark. For a
picture of a steel castor, see "Dazzle"]
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E
= Normal
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ej
= Japanese
[ not accepted in REX [excpet for tri-color];
responsible for harlequin patterns]
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e
= Non-Extension [necessary for Red]
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WHITE MARKINGS:
(called
"broken")
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En
= Broken Pattern
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en
= Self [Normal]
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{there are others but they are not significant in Rex}
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White markings fall into 3 categories:
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enen = solid colored; no white
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Enen = Broken, usually 10-90% color
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EnEn = "Charlie", usually < 10% color, typically around the
eyes,
ears, and down the center back
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