a. What are the two genotypes of the grandparents? b. What is the genotype of Jane's husband? c. What are the chances that Peter is the carrier of the PKU allele that resulted in his having an affected son? %

a. Rr, Rr

b. rr

c. 0% because its the women who transmits the disorder.

Explanation:

PKU allele is an autosomal recessive disorder which is caused by mutations in both alleles of gene for phenylalanine hydroxylase. Alleles are either dominant or recessive. When two alleles are identical means that mother and father cells are homoozygous recessive. They both are combining the same alleles causing it to have a higher chance of genetic disorder.

b is the best answer for this question.