The coat color in Labrador retrievers is controlled by two sets of alleles. The gene E/e determines whether the fur has pigment
or not and is epistatically dominant to the gene B/b, which controls the darkness of pigment when it is there. A breeder crosses a purebred black Lab with the genotype BBEE and a purebred yellow Lab with the genotype bbee, producing offspring that are black. A test cross is done between these offspring and an individual with the genotype bbee. What is the expected ratio of black:chocolate:yellow?
