The following is a pedigree of PKU that is associated with a mutation in the PAH gene. Note: Filled squares or circles represent PKU patients. Assume that no other mutation arises within the pedigree. Assume complete penetrance (ratio of disease genotype: disease phenotype is 1). The single nucleotide polymorphisms (SNPs); SNP1 and SNP2 that are TIGHTLY LINKED to the PAH gene (shown as shaded rectangle in the schematic below) are given for some of the individuals in the pedigree.

 a) What is the mode of inheritance for this form of PKU?
b) What is the probability that Individual 5 is a carrier of PKU?
c) If Individual 5 is carrier, what are her possible SNP genotypes? Note: Assume no recombination.
d) Based on the SNP profile, give all the possible genotypes of Individual 7 using “A or XA ” for the allele of PAH gene conferring the dominant phenotype and “a or Xa ” for the allele conferring the recessive phenotype:

1: A, G 1: T, G SNP1: 1 2 2: T, C 2: A, C SNP2: Allele 1 1: A, G 3 2: T, C 4 5 6 7 1: G, G 1: A, T 2: C, C 2: T, A 8 6 10 Allele 2 SNPs for Individual 1