Question

Blood groups of a couple are AB and O. The possible blood group of children would be
A) O group only
B) AB blood group
C) A or B
D) AB and O

Answer 1

Human blood type is determined through codominant alleles. There are three different alleles as found in four main blood groups as A, B, AB and O. The three alleles are A, B and O. Only two of these alleles can be found at the same time in a person’s cell. The A and B alleles are codominant and the O allele is recessive. Thus, we find four phenotypes as our blood groups, like A, B, AB and O.

Complete answer:

If the child would have to have an O blood group, both parents should have at least one O allele which is recessive.
In this regard, we can easily say that the options A and D are wrong.
If the child would have to have the AB blood group, one parent should have at least one B allele and other at least one A allele.
This proves that Option B is also wrong.

Additional information: There are 4 different maternal blood types and 4 different paternal blood types. So, in this regard, we can say that in order to predict the blood type of children, 16 different combinations would have to be considered.

Hence, the option C is correct. The possible blood group of the children would be A or B.

Note: Each biological parent donates one of their two ABO alleles to their child. A father who is blood type AB could pass either an A or a B allele to his son or daughter. In this category, this assumption is possible where the child has either blood type A (O from mother and A from father) or blood type B (O from mother and B from father).