Hair Colour
Hair color in rabbits is controlled by genes at several locations on the chromosomes. These genes act in conjunction with each other to produce quite a variety of different colors and patterns. Hair texture and length is controlled at other locations.
The basic colour genes in the rabbit are A through E, En, Du, Si, V, and W. Other genes act as colour modifiers controlling the intensity of certain colours or patterns. They include the Rufus modifiers, the plus/minus (blanket/spot) modifiers, and the colour intensifiers. These modifiers are not single genes, but multiple ones that pool their effects.
A rabbit has two possible pigments that can be expressed in its hair - dark brown and yellow. The absence of both pigments results in white fur. All of the colours possible in rabbit fur are simply combinations of these pigments or lack thereof. The expression can appear on the same or different hairs, in certain patterns, and in different intensities.
In general, rabbits that have long hair, such as Angoras, have diluted colour expression. Rabbits that have short hair, such as Rex, have more intense colour expression. This is because, given the same genetic background, the number of pigment granules in the hair is the same. In long hair the pigment granules are spread further apart from each other, giving a pastel colour. In short hair, the pigment granules are packed more closely together, making a more intense colour.
We can classify the colour genes into two groups. First, the colour pattern genes. These genes determine which pattern will be expressed: agouti, tan, or no pattern. All of the other genes are the colour genes. These genes determine the placement and intensity of the colour pigments on the hair.
The following table represents a list of the known genes, how they affect hair colour, and some examples of rabbits having these genes. These genes are listed in the order of dominance within each group. Taking all of the genes together, there are thousands of colour patterns possible.
http://mosaicrabbitry.weebly.com/rabbit-coat-color-quick-guide.html
Quick links to each gene set can be found in the footer of each page.
A working exsample.
+
aa,Bb,CC,Dd,ee Sooty Fawn
carrying Choc and Dilute
aa,bb,CC,dd,ee Lilac Tort
=
aa,Bb,CC,Dd,ee Sooty Fawn
aa,Bb,CC,dd,ee Blue tort
aa,bb,CC,Dd,ee Choc Tort
aa,bb,CC,dd,ee Lilac Tort
Genotyping Rabbits
By Amy Hinkle
(amysrabbitranch.com)
Genotyping a rabbit is not as hard as it may seem. All that is needed is basic knowledge of rabbit color genetics, breeding records, and the rabbit's pedigree with the correct colors written on it. See my list of genotypes for aid if needed.
1. Figure out the rabbit's color
2. Write down the genotype for that color, if there is a dominant gene, leave a space next to it to fill
it in.
3. Look at the sire's color and find the genotype for that
4. Fill in any blanks-like if the rabbit has to carry a recessive gene because the sire has it
5. Do steps 3 and 4 for the dam
6. Look at the breeding records-what colors did the rabbit have or sire? For example, if the rabbit is
black, but there was a blue in a litter they produced, then the rabbit has to carry dilute. Fill in any
missing blanks from this information that is possible.
Now what is written for the rabbit's genotype is what is known. But, if the gsires, gdams, ggsires, and ggdams are looked at then it can be guessed what else is carried.
Here's an example:
1. Rabbit's color: Black
2. Genotype: aa B_ C_ D_ E_
3. Sire's color: Blue, Genotype: aa B_ C_ dd E_
4. Fill in blanks, the rabbit must carry dilute as that is the only thing the sire can pass on from that
“set”: aa B_ C_ Dd E_ enen
5. Dam's color: chocolate tort, Genotype: aa bb C_ D_ ee
6. Fill in blanks, the rabbit must carry nonextension and chocolate because that is the only thing the
dam can pass on from those “sets”: aa Bb C_ Dd Ee
7. Breeding records show that the rabbit has sired litters with the following colors: black, blue,
chocolate, blue tort, and a REW
8. Fill in, the rabbit must carry REW (c): aa Bb Cc Dd Ee
Ta-da! The rabbit's genotype!
Of course, the genotype may not always be fully known, but at least it gives a clue. One can also do test breedings to determine what the rabbit carries. For example: if it is a blue rabbit that is thought to possibly carry REW, then breed the blue rabbit to a REW so you have a 50% chance at getting REW babies. Of course, if there are only three or four babies and no REW, you still can’t rule it out. After about ten babies or so it would be safe to make an assumption in this case. And of course, if there is a REW baby, you know the rabbit does carry it.