Question

John has type A blood. John's father has type O blood. Mary has type B blood. Mary's mother is type A. What will be the possible blood types of John and Mary's daughters?

A) AB only

B) A or AB only

C) B or AB only

D) A, B, AB or O

Answer 1

John and Mary's daughters could have blood types A, B, AB, or O, depending on Mary's genotype, which could be either BB or BO, combined with John's AO genotype. Therefore correct option is D

Step-by-step explanation:

The question is about predicting the blood types of offspring given the blood types of the parents. Since John has type A blood with a father who has type O blood, John must have the genotype AO, where O is the recessive allele. Mary has type B blood, and her mother is type A, which means Mary could be either homozygous (BB) or heterozygous (BO) for the B allele.

When combining John's genotype (AO) with Mary's possible genotypes (BB or BO), their daughters could have the following blood types:

• If Mary is homozygous (BB), the daughters could be either type A (genotype AB) or type B (genotype BO).
• If Mary is heterozygous (BO), the daughters could have blood types A (genotype AB), B (genotype BO), or O (genotype AO).

Therefore, the correct answer is D) A, B, AB, or O.