Looking at the pedigree below, determine the probability that IV-3, and IV-4 are carriers (heterozygous) of PKU. (Their great grandmother, whose circle is shaded, had PKU.)

If second cousins IV-3 and IV-4 were to procreate, what are the odds that they would have a PKU-affected child?

If IV-3 were to marry an unaffected man from the general population, what are the chances that he would be a PKU carrier (is heterozygous)?

What are the chances that they would have a PKU-affected child?