Pigments in some bears are the result of epistasis between 2 genes. The black coat color is only produced when both wildtype forms of genes D and E are present. When gene D (D-ee) is wildtype alone, offspring are white. When gene E (ddE-) is wildtype alone, offspring are brown. When no wildtype alleles are present (ddee) offspring are all white. Based on this describe the relationship between the genes D and E. D is dominant to E E is dominant to D Dis epistatic to E OE is epistatic to D