B Locus – Brown Dog Coat Color
Brown locus, also known as the B locus, generates a brown dog coat color. Tyrosinase-related protein 1 (TYRP1) is a protein within the melanocyte that alters the color of the skin and hair of animals. This gene is refered to as the B locus and is responsible for brown versus black coat color with brown coat colour inherited recessive to black..
The three alleles of the Brown (B) locus are designated bs, bd and bc, a combination of any two of which will cause brown coat colour.
In some breeds, such as Doberman Pinschers and Australian Shepherds, brown dogs are referred to as red.
MC1R and TYRP1 comprise an example of interactive effects between loci on a single phenotypic trait: back coat color. A dog is not black unless it has a dominant allele at both MC1R and TYRP1.