Have you ever heard of a rabbit color called “self chinchilla”? You won’t find it in the Standard of Perfection, but if you talk very much with enthusiasts of rabbit color genetics, the name will probably come up. But what is a self chin?
The short answer is that a self chin looks exactly like a black (usually). Genetically, the only difference between a true black and a self chin is that one has the “full color” gene C and that one has the “chinchilla gene,” which we write as cchd.
The chinchilla gene can mess with eye color. It can cause blue, blue-gray or mottled eyes in rabbits that are not dilute otherwise, and brown eyes in dilutes such as squirrels. So if you ever have a self with the wrong eye color, consider self chin. A self chin can be black, blue, chocolate, or lilac — because the brown and dilute genes have nothing to do with making a self chin.
Here’s a broken black Satin doe that is actually a self chin. The reason: chinchilla in her background. The giveaway: the blue-gray eye. The disqualification: also the blue-gray eye.
The long answer:
Why is there (sometimes) no difference in appearance between a black and a self chin?
The only difference between a true black and a self chin is that one is C_ and the other is cchd_, correct? So let’s look at other colors that have that one difference:
What do you notice? That the C-based colors have a yellowish tint somewhere, like in the ring color of chestnut and in the trim on otters. The chinchilla based colors are exactly the same, except that the yellow is turned to white.
A black isn’t showing any yellow to start with, so changing it’s yellow factor to white doesn’t change the appearance of the rabbit. We get even deeper into the genetics later in this article.
Can you show a self-chin? How should you use one in breeding?
A self chinchilla looks just like a black, blue, chocolate, or lilac. Assuming it has the normal eye color, it is acceptable to show it as a black, blue, chocolate, or lilac, because the ARBA varieties are based on appearance, not genetics.
In your breeding however, it’s important to remember that you’re working with the chinchilla gene and not the full color gene. The do’s and don’ts for breeding self chins varies by the breed, because different breeds recognize different colors. However, in most breeds you don’t want the chinchilla gene mixed with non-extension such as tort or orange, ever. A self chin is useful if you are tying to get chinchillas or silver martens, or frosties. Otherwise you don’t really want it around.
A self-chinchilla (if the eyes are brown) can be registered as a black, again because ARBA varieties are based on appearance. On the pedigree, you can list black (or blue, chocolate, or lilac) as the variety, but if you want to be of help to whoever buys that rabbit’s descendants, you can put “self chin” in parentheses.
How do you know if you have a self chinchilla?
Here are some clues:
1. Does your self colored rabbit — black, blue, chocolate, or lilac — have incorrect or mottled eye color? This isn’t a necessity, but can be an indicator.
2. Is your self colored rabbit out of chinchilla or silver marten lines?
3. Breed it to a REW, preferably one that you know is an agouti or tan. Did you get any chestnuts or otters? Any torts, oranges, or creams? Then it is definitely NOT a self-chin. Breed it to a chinchilla or a silver marten. Did you get any otters, opals, or chestnuts? Then it is definitely not a self-chin. All the test breeding possibilities would take a long time to explain, but basically if you breed a black to a rabbit with a lower c-series gene and you get a full color C- variety, it’s not a self chin.
4. If neither of it’s parents show the full color gene, it cannot be a true black. A true black CANNOT be out of TWO chinchillas, silver martens, sable martens, seals, smoke pearls, smoke pearl martens, sables, REW’s, or himalayans.
Now here’s the really interesting coat color genetics stuff…
All rabbit varieties are created by the interplay of two “colors of paint”. A more correct term would be “pigments”. Some of the ABCDE gene series change the shade of the pigments, and others change how they are arranged.
The two pigments can be referred to as “light” and “dark,” for the purpose of making things easier to understand.
Chestnut Agouti is the original color, the wild rabbit color, and a true-breeding chestnut has a genotype of AA BB CC DD EE. In the chestnut you see the lovely interplay of the two pigments in their original intended form; see how they harmonize in the ring color, the lacing, the ticking, the undercolor.
A Chinchilla is just a chestnut with the “cchd” gene. You’re seeing the same pattern, but the “light pigment” is turned to silver, where on the chestnut it is yellow.
For interests sake only, let me continue to explain that the lower C-series genes further strip the two pigments of their intensity: the sable gene “cchl” turns the dark pigment from black to brownish. The himalayan gene “ch” removes all the color except on the points. The REW gene “c” removes the pigment entirely from the fur and eyes.
Back to self chin:
So the “C” series plays on the color of the pigments. The A series modifies how the two pigments are arranged on an animal.
The gene we call “A” or “agouti” is the normal harmonic arrangement of the pigments.
The gene we call “a” or “self” doesn’t allow the lighter pigment to show in the normal fashion. That’s why a sable chin becomes a Siamese sable, an opal becomes a blue, and a chinchilla becomes … a self chin!
(This is beside the point, but a tan pattern is somewhere between an Agouti and a Self; in fact it’s kind of like self on top and agouti on bottom!)
I could go on for a long time about how the different genes play on the pigments, but I guess that would be getting off topic. I think it’s very interesting in theory, without getting into the biochem.
If you’d like more information about rabbit coat color, check out “A book About Bunny Colors,” the Practical Breeder’s Guide to Rabbit Coat Color!