B Locus
Affected gene: TYRP1
 Inheritance: Autosomal
 Mutation:
 
 
bc = T>A, Chr11:33317810
 
 
bd = 3 bp deletion (del CCT), Chr11:33326727–33326729
 
 
bh = G>A, Chr11:33317814 (Husky)
 
 
bs = C>T, Chr11:33326685

Description:
Dogs that carry two copies of the b allele produce brown pigment instead of black pigment in their coat and skin. Dogs carrying only one copy of the b allele will produce black pigment but can pass the b allele on to their offspring.
Dogs that are ee at the E locus and carry two b alleles have a red or cream coat, but their nose, eye rims, and paw pads are brown (sometimes referred to as a Dudley nose in Labrador Retrievers).
The terms liver or chocolate are commonly used to describe brown pigmentation in most breeds; in the Doberman Pinscher, this color is referred to as red