Now, since each gene, as we said earlier, has an additive effect, what that means is the more uppercase letters that we have in a given person, the darker the skin color of that person is. So since each gene has an additive effect on the skin color, the more capital letters we have, the darker the skin is and vice versa. The smaller the number of capital letters is, the lighter the skin color of that particular person. So for example, if in a given individual all of these genes contain the uppercase letter, so these are uppercase A, these are uppercase B and these are uppercase C, then we have uppercase AA, uppercase BB, uppercase CC. And this represents the darkest possible skin color and likewise if all of these are lowercase letters so lowercase A, lowercase A, lowercase B, lowercase B, lowercase lowercase C, lowercase C then we have the lightest possible skin color. Now to further demonstrate how this added effect in polygenic inheritance actually works, let's carry out the following experiment.