4. Pnenymetcnuna {Pam} is a cieeace charactenzec my me Iaca at an enzyme that ncrmally ccnuerta the amine acid phenyalahine intc ancther amine acid, tyrceine. Instead the phenylalanine is converted into texic prcducta. which accumulate and damage the central newcue system. The ultimate result is severe mental retardatien. A man and a wcman each carry the allele fer PKU. thcugh neither has the disease. What is the probability that this child is a carrier cf the n::li1=.eaec'.7I