Human Heredity 11th Edition by Michael Cummings

Exercise 25

Height in humans is controlled by the additive action of genes and the action of environmental factors. For the purposes of this problem, assume that height is controlled by four genes- A , B , C , and D -and that there are no environmental effects. Assume further that additive alleles contribute two units of height and partially additive alleles contribute one unit of height.
a. Given these assumptions, can two individuals of moderate height produce offspring that are much taller and shorter than either parent? If so, how can this happen?
b. Can someone of minimum height and someone of intermediate height have children taller than the parent of intermediate height? Why or why not?