[Campbell Biology P.341] A man with type A blood marries a woman with type B blood. Their fi... | Practice Question

A man with type A blood marries a woman with type B blood. Their first child has type O blood. What are the genotypes of the man, the woman, and the child?

  • A: Man: IAIA, Woman: IBIB, Child: ii
  • B: Man: IAi, Woman: IBi, Child: ii
  • C: Man: IAi, Woman: IBIB, Child: ii
  • D: Man: IAIA, Woman: IBi, Child: ii

Explanation

The child has type O blood, which means their genotype is ii. To have this genotype, the child must inherit one i allele from each parent. Since the man has type A blood, his genotype must be IAi. Since the woman has type B blood, her genotype must be IBi. Both parents must be heterozygous to produce a type O child.