Ryan (II-2) and Rachel (II-3) already have one son with phenylketonuria (PKU). They are about to have twins (III-2 and III-3) so they come to you for genetic counseling. You identify an RFLP that is 5 m. u. away from the PKU gene and are able to obtain a family history from Ryan whose sister has the disease. Answer the following questions assuming II-1 and III-1 inherited nonrecombinant chromosomes from their parents. To be consistent in notation, A/a refers to the PKU gene and the numbers refer to the polymorphism. How many different alleles for the polymorphism can we see here