Name:_____________________________________________________ Date:_____________________Score:__________ PROBLEM SET 5 Polygenic Inheritance and Sex Related 1. If skin color is caused by additive genes, explain your answer to the following: a. Can mating between individuals with intermediate colored skins give birth to lighter-skinned offspring? b. Can such mating produce dark-skinned offspring? c. Can mating between individuals with light skins produce dark-skinned offspring? 2. Nystagmus is a condition in humans characterized by involuntary rolling of the eyeballs. The gene for this condition is incompletely dominant and X-linked. Three phenotypes are possible: normal, slight rolling and severe rolling. A woman who exhibits slight nystagmus and a normal man re considering marriage and ask a geneticist what the chance is a. that their female children will be affected and to what degree? b. that their male children will be affected and to what degree? (Use letter N and n) 3. A man who is heterozygous for pattern baldness marries a non-bald woman who is also heterozygous for the trait. What is the P that? a. a son of theirs will be not bald? b. a daughter of theirs will be bald? 4. Recall that human sex chromosomes are XX for females and XY for males. a. Does a male child inherit his X chromosomes from his mother or father? b. With respect to an X-linked gene, how many different types of gametes can a male produce? c. If a female is homozygous for an X-linked gene how many different types of gametes can she produce with respect to this gene? d. If a female is heterozygous for an X-linked gene, how many different types of gametes can she produce with respect to this gene?
