Part III (Do Part II first): Below is a pedigree of a human genetic disease in which solid color indicates affected individuals. Assume that the disease is caused by a gene that has two different alleles A and a, and the disease allele is rare. If the female 4 marries an affected man (exhibiting the disease) whose parents are both heterozygotes, what is the probability that they will have a normal child? (Hint: First, consider the probability that the affected male has the genotype needed for the couple to have a normal child.)
Its a dominant disease. The female is heterozygous


1/4
1/8
1/3
1/2
1/6