One of the simplest Loci, the Black Locus, or B Locus, controls the whether the fur is black or chocolate based and there are only has two different genes: B for black and b for brown. There are only three possible pairs that a rabbit could carry: BB, Bb, or bb.
The ‘B’ or Black Gene
- Completely dominant, so it is possible for a rabbit to carry the ‘b’ chocolate gene even if the rabbit expresses the ‘B’ gene.
- Makes the fur color black based.
- Common colors range from Black Chinchilla and Black self to Black Silver Tipped steel and Opal.
Black Chinchilla (A_B_c(chd)_D_E_)
Black Silver Tipped Steel (Black STS) (A_B_c(chd)_D_E(s)_)
The ‘b’ or Brown Gene
- Makes the fur color chocolate based.
- Completely recessive. For this reason, when it the gene is expresses, it is always listed on a genotype or phenotype as a pair (bb) when it is expressed.
- Possible colors include Chocolate Chestnut, Chocolate Sable, and Chocolate Chinchilla.
Chocolate Chestnut Agouti (A_bb_C_D_E_)
Chocolate Chinchilla (A_bbc(chd)_D_E_)
Broken Chocolate Sable (aabbc(chl)_D_E_)
Interested in learning about the other four color Loci? Check out the Rabbit Coat Color Genetics page!