Often, the dominant genes can interact to produce an effect that is missing when either one of the genes is present without the other dominant in the genotype. Still one of the dominant genes may suppress the action of the other dominant
(Epistasis) whenever the two are present together. Still, both dominant genes might produce the same effect whether they are present together or not. In another type of interaction, one of the dominant genes may produce an effect when by itself but in the presence of the other dominant gene, a totally different phenotypic effect might be produced. In still another case, one of the dominant genes might totally suppress the other dominant gene but fail to produce any effect of its own. These relationships are shown on the right. Click on the ratio at the top of the screen which you think best describes the interaction detailed in the example.
