Inheritance of coat colour in the Hovawart dog

The three recognised colour varieties of the Hovawart breed of dog, black, black and gold and blonde, are due primarily to combinations of the mutant alleles solid black (A^s), black and tan (a^t) of the agouti series and the non-extension of black allele (e). The e allele is epistatic to the agouti alleles, thereby reducing the four possible phenotypes to three.