試題詳解

8. The Y substance is needed for the proper phenotypic expression of the A, B, and AB blood types in the ABO blood typing system in humans. Individuals who are recessive for the Y substance (yy) will have a type O phenotype, even if they have the A and/or B alleles. Two individuals, each with type AB blood and heterozygous at the H locus have children. What is the probability they will have a child who is phenotypically type O?
(A)1/8.
(B) 3/8.
(C) 3/16.
(D)4/16.
(E)6/16.