1.What is the probability that a sperm from the father will contain the PKU allele?
Probability = ½
2.What is the probability that an egg from the mother will contain the PKU allele?
Probability = ½
3.What is the probability that their next child will have PKU?
Probability = ¼ (because each parent has ½ chance ½ X ½ = ¼)
4.What is the probability that their next child will be heterozygous for the PKU gene?
Probability = ½ (because each parent has ½ chance of donating the ‘P’ allele and ½ chance of donating the ‘p’ allele (½ x ½) + (½ x ½) = ½