Question

two parents, one with type o blood and one with type ab blood, have several children. remember that the three possible alleles that might contribute to the two copies of the gene for each person are ia or ib (codominant with each other) or i (recessive to the other two, necessary for recessive type o). what blood type is not possible for the children to show?

Answer 1

Answer: They cannot have a child with AB blood.

Step-by-step explanation:

The parents have type O and type AB blood. The O allele is recessive to both the A and B alleles, meaning that for a person to be type O, their genotype must be OO. When crossed with AB blood, they will only have an O allele to contribute. See the punnet square below:

A B

O AO BO

O AO BO

As shown above, when crossed with a person who is AB, their offspring can only be Type A (AO) or B (BO). An offspring who is AB cannot occur when one parent is O, because they do not have an A or B allele to contribute. (O is recessive to A and B, you cannot be O unless you have 2 of the O alleles).