Basic Color Genetics: Black and Chocolate

We spent several days studying the non-agouti black gene family (aaB-).  Today we will start studying the non-agouti chocolate family by comparing the color genes of black and chocolate.   B is for black and b is for brown.  Brown in rabbits is called chocolate.   Chocolate is recessive to black.   

We have read about the black color genes in the previous posts:
aaB-C-D-E-
It is a non-agouti pattern in the black family, full colored, dense color and the color is extended to the entire body.     Today's topic is to look at the B location.   An upper case B stands for the dominant gene, the - after the B indicates it could have another B gene or a b gene.  If it has a b gene, that means the black rabbit carries chocolate even though one cannot see it.   

Chu's LaNelle is in both of these photos. 

This is a chocolate English Angora, it's color genes are:
aabbC-D-E-
The above color genes translate to the following: chocolate is a non-agouti pattern, it has two chocolate genes that are recessive to black gene B, it's a full colored rabbit, the color is dense and it is extended to the entire body.   
If you compare with the black color gene above, you'll see the difference is in the B location.  The black is B- while the chocolate is bb.   There may or may not be a b hidden under the black but we know for sure that a chocolate cannot carry black as b is recessive to B.   
 

Since chocolate is recessive to black, two chocolate cannot produce a black offspring but two black may produce a chocolate offspring if there are chocolate gene b hidden behind the B gene.   The color of the eyes is brown because of the D dense color gene.  In both photos is Chu's Chocolate Kiss at about 8-9 months old.