3. A dominant gene (Dt) interacts with a₁ to give dotted aleurone. Dt does not interact with a₂, c or r. Seeds of a₁^p a₁ A₂ C R Dt constitution have a pale purple background on which appear the more intense dots. The ratio of the number of dots on seeds of a₁ a₁ a₁^p A₂ C R Dt Dt dt genotype to the number of dots on seeds of a₁ a₁ a₁ A₂ C R Dt Dt dt constitution is 2 : 3, while the ratio for seeds of a₁ a₁^p a₁^p A₂ C R Dt dt dt to seeds of a₁ a₁ a₁ A₂ C R Dt dt dt constitution is 1 : 3.8. These ratios suggest that the dosage of a₁ affects the number or else that a₁^P has an inhibitory effect which is proportional to the dosage of a₁^p. Dt is not linked but is independent of a₁, a₂, c, r, su and lg.