Question

If a man with type AB blood marries a woman with type O, what blood types would you expect in their children? What fraction would you expect of each type?

Short answer

If a man with type AB blood marries a woman with type O, the children will have blood types A and B. Each blood type will be a fraction of ½. This is because ‘A’ and ‘B’ alleles are dominant alleles on ‘O’. So O allele will not show its effect in heterozygous conditions.

Step-by-step solution

Step 1: Blood types

A human being has a specific blood type determined by the genes that the individual gets from their parents. There are four types of blood groups based on the type or presence of antigens in the blood: O, A, B, and AB.

An individual with blood group A has A antigens and anti-B antibodies in the blood, and an individual with B blood group has B antigen and anti-A antibodies in the blood. Blood group O has no antigen but has both the above types of antibodies.

Blood group AB has both the above types of antigens but does not contain any antibodies.

Blood

Blood is the vascular connective tissue with a liquid matrix circulating in the body that supplies nutrition and oxygen to every part of the body. It also removes waste excreted by cells in the body.

Step 3: Genetics of blood type

The man with AB blood type is heterozygous with alleles IA and IB. The woman with O blood group is homozygous recessive with IO allele. So the genotype of man is AB and of woman is OO. According to the Punnet square method, genotypes of offspring will be A and B.