Height in humans depends on the additive action of genes. Assume that this trait is controlled by the four loci \(R, S, T,\) and \(U\) and that environmental effects are negligible. Instead of additive versus nonadditive alleles, assume that additive and partially additive alleles exist. Additive alleles contribute two units, and partially additive alleles contribute one unit to height. (a) Can two individuals of moderate height produce offspring that are much taller or shorter than either parent? If so, how? (b) If an individual with the minimum height specified by these genes marries an individual of intermediate or moderate height, will any of their children be taller than the tall parent? Why or why not?

If so, how? If an individual with the minimum height (all PP genotypes with 8 units of height) marries an individual of intermediate or moderate height, can any of their children be taller than the tall parent? Answer: Yes, two individuals of moderate height with all partially additive alleles (AP) can produce offspring that are significantly taller or shorter than either parent. Their offspring can inherit a different combination of alleles, potentially producing much taller offspring (by inheriting all additive alleles, total height contribution of 16 units) or much shorter offspring (by inheriting all partially additive alleles, total height contribution of 8 units). However, if an individual with the minimum height (all PP genotypes with 8 units of height) marries an individual of intermediate or moderate height, none of their children will be taller than the tall parent, as the maximum height contribution possible for their offspring would be 12 units.