Question

 

1)    Phenylketonuria (PKU) is a human autosomal genetic disorder in which the affected individual cannot metabolize the amino acid phenylalanine. The disease is characterized by severe mental retardation if left untreated. The disease is caused by homozygosity for a recessive, mutant allele. If two parents are heterozygous for the allele, what is the probability that their child will have PKU?

Answer 1

1/2×1/2= 1/4