# Genetics C locus (chchd)?



## Upper Penn Love (May 14, 2013)

I'm trying to figure out the product of a Cali (aaBBchchDDEE) x solid black satin (aaBBCchdDDEE). I just can't figure out what the C alleles will do. Punnet square gives me 50% solids (Cch) and 50% ? (chchd??) not sure what that is and google isn't helping much.


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## Upper Penn Love (May 14, 2013)

Would this result be the chinchilla coloring since that's dominant over the himalayan points?


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## Bunnylady (May 14, 2013)

Are you sure the Satin has the chinchilla allele (cchd)? The chinchilla alelle removes the yellow pigment from the coat, and also a little bit of the black. In an Agouti, the reduction in black isn't all that noticeable, but the lack of yellow in the intermediate band stands out. In a self-patterned animal, you can't tell whether there is yellow there or not, because the black covers it up. There is slightly less black pigment even in a self, but you might have to put one next to a full-color self to see the difference. (My favorite way to show this to people involves putting a Black Otter next to a Silver Marten. The Silver Marten is cchd, and the black of the body is a couple of shades less intense than the Black Otter, which is C). Some rabbits with the cchd allele may have gray or mottled eyes; a black rabbit with gray eyes is unmistakeably a self-patterned Chin. On a show table, the gray-eyed self Chin would be DQ'd for having the wrong eye color, a self Chin with brown eyes would just get marked down for poor color.


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## Upper Penn Love (May 14, 2013)

I'm not looking at a particular animal, it just came up in my punnet squares I was doing just to see what I'd be looking for for certain colors in offspring of the rabbits I do choose. Obviously there's lots of room for error as it will be hard to guess recessive genes on rabbits I look at. Thanks for the tip on the eyes, first hand knowledge/indicators like that are hard to come by, but showing will be more of a bonus if I do it, I'm more concerned with meat and more relevant to this; pelts. These are the websites ive been looking at http://www.threelittleladiesrabbitry.com/breedingcolorchart.php and http://dubaysrabbitry.weebly.com/rabbit-color-genetics.html they kind of contradict each other in this very case though. The first uses Cchd for chinchilla while in the second it seems like the same code would be cchd with a lower case, or rather "chdc" (among other possibilities). I believe it states that with the capital that would be a solid color. Of course I've figured out chins have the dominant A whereas solid color would have aa also. 

Anyway now that I'm looking back at the original post, I took that black satin "Cchd" from the 2nd website, which portrays the capital C is dominant and can hold the chin "chd" as recessive thus being C-chd. ?? I guess the contradicting info from a google search doesn't always help lol

I've spent the better part of my day off trying to figure this all out and I can't believe how little I've learned and only with the C locus. Thankfully, the colors I want are all the same and dominant except for the A and C loci. I can't imagine what I'd face if I chose opposites or something more complicated.


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## Bunnylady (May 15, 2013)

The problem with working with an animal that is expressing a dominant alelle, is that you can't be sure it isn't carrying a recessive allele. An example of that would be a rabbit I once owned. Both of its parents were Chestnuts; everything on its pedigree was a Chestnut (A_B_C_D_E_). This particular rabbit was a Sable Point Marten (ataB_cchlcD_ee). The breeder was so surprised at all those recessives, his reaction was, "what the heck is_ that_?" 

Unfortunately, this business of typing things on keyboards for webpages doesn't have a system for doing what are, effectively, exponents (you remember those from math, right, "two to the tenth power," and all that?) I really don't know; how would I type "two to the tenth power" numerically? I haven't a clue on how to get those numbers to sit in the space above the line. The same kind of thing applies to the letter symbols that we use for the various alleles in the gene series. At the B locus, things are nice and simple; there are only 2 alleles, the dominant B (black) and the recessive b (chocolate). But the C series is very complex. The allele that codes for the highest possible production of both the yellow and black pigment conveniently is also the most dominant, so it is designated with the capital C. The allele that codes for no pigment, neither black nor yellow, is also the most recessive, it is designated c (the Ruby-Eyed White is a true albino, though we don't call it that in rabbits). The problem is all those alleles between the two extremes. Some say there are 3 alleles in between, some say 4. How to designate them? Well, since they are recessive, they must start with a lower-case letter - in this case, c. Then they added other letters, which properly expressed come above the line. So, the Himilayan allele is written as ch - though for the life of me, I don't know how to write the "h" above the line. The people who first figured out the genetics of coat color referred to the pattern of black pigment but no yellow pigment as "chinchillation;" they also noticed that the amount of black pigment differed in those rabbits called Chinchillas. They attached further letters to indicate the amount of "chinchillation" that was being coded for by that particular allele. So, the ladder of dominance in the C series is as follows:

C      - full color. Most dominant, codes for the maximum amount of both black and yellow pigment
cchd - "dark chinchillation" Removes all (or nearly all) of the yellow pigment, and a little of the black pigment
cchm - "medium chinchillation" (the existence of this alelle is still debated) Removes all of the yellow pigment, and some of the black as well
cchl - "light chinchillation" Removes all of the yellow pigment, and a lot of the black, particularly on the body. Combined with self at the A locus (aa), this produces Siamese patterning
ch     -  Himilayan. Removes all of the yellow, and only allows black to appear on areas where the skin temperature is cooler (ears, nose, feet, tail). Red eyes.
C     -  Ruby-eyed White. True albino, neither yellow pigment nor black appears in any area of the coat. 

The really confusing thing about this series, is that while the top allele is fully dominant and the bottom one is fully recessive, all those in between are partly influenced in their expression by what they are paired with. For example, I said the cchl allele produces Siamese patterning. When you have one cchl and one of either the ch or c, you have a Siamese Sable. These rabbits are brown on the body, and nearly black on the points. The rabbit expresses the most dominant member of the pair, in this case the cchl, but just how dark or light the "chinchillation" is depends on what the other allele is. The rabbit with ch will be darker on the body than the one with c - which shade is preferable depends on what the breed standard for that particular rabbit is. A rabbit with two copies of the allele (cchlcchl) will be darker still - so dark as to be nearly black; a color that is called Seal.

Is your head hurting yet?


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## Upper Penn Love (May 15, 2013)

Lol no my heads not hurting yet. I see what your saying, very interesting. It makes a lot more sense with the examples, I think I had the idea that they all had there own step on the ladder or that cchd and cchl were equal and it was random which showed through, but I see they actually effect each other. The soup bowl theory rather than salad bowl lol <~ sorry, something a professor once told me when debating which "bowl" described the cultures within the U.S.

I know it doesn't really help much but this is what I used to do for exponents via email. We would use the ^ symbol to signify that the next number (ect) was an exponent. It does end up looking kind of confusing if the other person doesn't understand what your doing though. a^t aB_cch^l cD_ee (your example below... If I did the exponent right lol)

Your extremely helpful on the subject and I particularly like genetics although I've only felt with very easy stuff, nothing as complicated as this lol

Maybe you could give me your advice on the trio I'm hoping to find and just troubleshoot if I haven't figured something out completely. With 3 rabbits (1buck 2 does) I'd like to get an average of 50% chin, 25% solid black, and 25% cal offspring, allowing for the possibility of random recessive genes to effect this total outcome. 

1st doe: Because of the dominant A gene in the chin, that would be a doe (and now it seems i should be looking for a seal doe actually)and I'd have to try to find a homozygous one for the c series. And that would produce 100% chins when paired with my imaginary buck. A_B_cchlcchlD_E_ (preferring all unknowns be dominant but can't know)

2nd doe: choosing this to be my solid black. Either Cch or Cc depending on whether or not my buck possibly carries the albino gene. aaB_(Cch or Cc)D_E_

Buck: Cal coloring. Either homozygous for the points gene or carrying the albino gene if I can get my black doe without it. Buck with the 1st doe should produce all chins and buck with the 2nd doe should produce 50% black 50% points... aaB_(chch or chc)D_E_

I ran into problems if I had the buck as either of the other 2 colors. There were other option in combining genetic codes between the 3 but they were all more complicated with the recessives ( such as a chin doe with resessive for points and a black with recessives for chin or something similar) so the above is what I settled on...today lol


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## Bunnylady (May 15, 2013)

What everyone except the guys who mapped this out considers a Chinchilla is  the _dark_ chinchilla allele (c^chd). A good chin has 2 copies of the chin allele. If a rabbit inherits one copy of that and one of c, the animal usually shows a good band on the outer end of the hairs, but maybe no under color next to the skin. 

If you get a doe that is a pedigreed representative of one of the Chinchilla breeds, you can be reasonably sure she'll have 2 copies of both the Agouti allele at the A locus, and the Chinchilla allele at the C locus. Such an animal should produce 100% Chins when bred to a Cal. If she just happens to be the Chinchilla colored offspring of a couple of crossbreds, she may have a self allele at the A locus (Aa), so she may produce self offspring [when bred to a Cal, which is a self (aa)]. She might have something other than a pair of cchd's at the C locus, too, so you might get Cals or something else interesting as a result.

Things get really fun when you are breeding to animals with New Zealands  or Californians in their background. Apparently, it is common for animals of those breeds to have the Steel allele (E^s). Steel is actually dominant to the full-color allele in the E series, but it was identified after the full-color allele was already given the upper-case designation. So, the E series has two capital letters in the series (oops!). Steel is really weird; if it is paired with the full-color allele, the animal is a visual Steel (a narrower light-colored band on the hairs gives the animal a very dark version of the Agouti pattern). If the Steel allele is paired with any other allele in the E series (including another Steel) the animal look exactly like a self (aa). Obviously, this could dramatically skew the ratios of the kits' colors.


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## Upper Penn Love (May 16, 2013)

Oh my lol


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