Domestic Rabbit's Color Genes - The C Series Part 2

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What Happens When You Breed C-genes together?

Just like with other genes, if you breed two true-breeding color gene domestic rabbits together, you will have offspring of the same.  That is, two true-breeding full color (“C-C”) rabbits will produce all “C-C” offspring.  Two true-breeding chinchilla rabbits (“cchd-cchd“) will produce chinchilla color family offspring.  Two seals will produce seals (they are always true-breeding).  Two true-breeding Himalayans will produce only Himalayans.  Two ruby-eyed whites will always produce ruby-eyed whites (they also are always true-breeding).  However, no true-breeding sable rabbit exists since a rabbit with two sable genes is a seal.  Rabbits who express the sable gene always carrying either a Himalayan gene (“ch“) or a REW gene (“c”).

Of course the fun and uncertainty starts when you breed rabbits with different color genes together.  Let’s take a look at a few different combinations.

Since we’ve already touched on the idea that there are no true-breeding sable rabbits, we’ll look to see what happens when we breed two rabbits that are expressing the sable gene, such as two sable points.  We’ll make one parent carry the Himalayan gene and the other the REW gene.  You will get approximately half sable rabbits, 1/4 seal rabbits and 1/4 Himalayans rabbits, on the average.  Look at the chart below to see how this works.

 

cchl-c x cchl-ch

Sable Carrying Himalayan

cchl Gene

ch  Gene

Sable Carrying REW

cchl Gene

cchl cchl

Seal Color

Family

cchl ch

Sable carrying Himalayan

c Gene

cchl c

Sable carrying REW

ch c

Himalayan carrying REW

What happens when you breed a true-breeding full color rabbit (C-C) with a chinchilla color family rabbit that carries the sable gene (cchd x cchl)?  You will find that anytime you breed a true-breeding full color rabbit with any other rabbit, all of the offspring will be full color rabbits.  The offspring will carry the other parent’s genes, however, and can be expressed in future generations.  Let’s look at the results of the “CC” x “cchd-cchl” rabbits.

 

C-C x cchd-cchl

Chinchilla Carrying Sable Gene

cchd Gene

cchl  Gene

Full Color

C Gene

C cchd

Full Color Carries Chinchilla

C cchl

Full Color Carries Sable

C Gene

C cchd

Full Color Carries Chinchilla

C cchl

Full Color Carries Sable

 

You may wonder whether you can get a sable, chinchilla, Himalayan or REW from breeding two full color rabbits, such as two black tortoiseshells.  The answer is definitely, “Yes.”  Remember that the other color genes can “hide” under the more dominant full color gene.  By looking over a rabbit’s pedigree you can get an idea of what could be lurking, but that doesn’t preclude a surprise.  Ancestor rabbits may have other-color-gene siblings that you can’t see on your rabbit’s pedigree.  If you had the whole family tree, it might make more sense. 

 

In any case, let’s see what happens when we breed a full color rabbit that carries the REW (“c”) gene with a full color rabbit that carries the sable gene (cchl).  The resulting offspring are primarily full color rabbits, but a half of them carry the other color genes and 1/4 are sable gene color family rabbits.  Take a look at the table below to see how this happens.

 

C-c x C-cchl

Full Color Carrying
Sable Gene

C Gene

cchl  Gene

Full Color
Carrying
REW

C Gene

C C

True
Breeding
Full Color

C cchl

Full Color Carries Sable

c Gene

C c

Full Color Carries REW

cchl c

Sable Color Family Carries REW

 

 

Test Breeding for Color Genes with REWs

Sometimes we do get puzzling results from breeding domestic  rabbits.  Phenotypes (what you see) are sometimes easy to confuse.  But by using a REW, you can test the color genes of a particular rabbit.  Because the REW is definitely and obviously “c-c,” all offspring will exhibit the color genes of the other parent (remember, since “c” is the least dominant, nothing can “hide” under it).  It does not matter whether the doe or buck is the REW, the process works the same way.  [Note: you cannot use a blue-eyed white in this way; blue-eyed whites have a totally different genetic make-up.]

Perhaps we have a rabbit that we think is either a broken seal or a broken black [Note:  solids can be distinguished from the fur on the bottom of their feet–blacks have gray around their footpads and seals have brownish sepia color around their footpads; brokens have white].  Approximately half of the offspring will have one of the color genes of the tested rabbit while the other half will have the other gene.  If even one of the resulting offspring shows a full color gene, the tested rabbit is black.  If all of the offspring are sable color family rabbits (and there are enough offspring to eliminate errors of chance), the rabbit is probably a seal.

Note that all offspring in this case carry the REW gene.  Breeding two of the resulting offspring together can produce more REWs.  The top chart shows a REW bred with a full color rabbit that carries the sable gene.  The second chart shows a REW bred with a seal.  Notice that both pairings can produce sable family color rabbits, but only the black can produce the full color rabbit.

 

c-c x C-cchl

Full Color Carries Sable Gene

C Gene

cchl  Gene

REW

c Gene

C c

Full color Carries REW

cchl c

Sable Color Family Carries REW

c Gene

C c

Full color Carries REW

cchl c

Sable Color Family Carries REW

 

 

c-c x cchl-cchl

Seal

cchl Gene

cchl  Gene

REW

c Gene

cchl c

Sable Color Family Carries REW

cchl c

Sable Color Family Carries REW

c Gene

cchl c

Sable Color Family Carries REW

 cchl c

Sable Color Family Carries REW

 

The example breedings above are only a few of the crosses that can occur with regard to the color gene.  There are 120 different breedings considering only the color gene!  By applying the same procedure, you can calculate your chances of producing the different types of offspring for any of those 120 combinations.

C-locus Color Families in Domestic Rabbits

I use the term “color families” to describe groups of colors that vary by only one gene.  Every color belongs to a number of color families.  You can use your knowledge of color families to help you breed for specific colors (and to understand how colors are produced by certain breedings).  Since color family rabbits only vary by one gene, they are the next best thing to breeding two rabbits of the color you are attempting to produce.

Conclusion

The color gene is one of the most complicated of all genes that determine rabbit fur color.  The color gene controls where color will show and how much will show there.  There are five color genes that produce six color families:  full color, chinchilla, seal, sable, Himalayan and REW.  The genes range from full color over the entire body (“C”) to no color (“c”).  The sable gene is often thought of as a shading gene, but the ee gene can also produce a type of shading.

Less dominant/more recessive genes can hide under other color genes.  You can use REWs to test for color genes in domestic rabbits.  Knowing how colors are related to each other, that is, those that vary by only the color gene, can help you produce the colors you desire.

Next Article: the Dilute Series