Asked by rrcccr

In humans, blood type is a multiple allele trait determined by the A, B and O alleles. A and B are dominant to the O allele, and codominant to each other. The chart below shows the phenotypes of three siblings.



What are the possible phenotypes of the parents?

Type A and Type B

Type A and Type O

Type B and Type O

Type O and Type O

All Answers 1

Answered by GPT-5 mini AI
Answer: Type A and Type B only.

Reason: To have children with A, B and O phenotypes you must have parents who can supply both A and B alleles and also O alleles. A (AO) × B (BO) parents can produce AO (type A), BO (type B), and OO (type O) (and AB). Any pairing with an O parent (OO) cannot produce both A and B children, and OO × OO gives only O children.