Question

Three sets of parents in the hospital had babies whose blood types are given.
Parents Children
Mr. & Mrs. White BABY 1
Type B and O Type A
Mr. & Mrs. Black BABY 2
Type AB and O Type B
Mr. & Mrs. Brown BABY 3
Type A and B Type O

BABY 4
Type AB
The phenotype of the parents of Baby 4 could be

• A. The Whites
• B. The Blacks
• C. The Browns
• D. The Browns or the Whites
• E. The Blacks or the Whites

Answer 1

The correct option is C The Browns

Baby 4 has AB blood group. To have a child with AB blood group, one parent should have at least one $I^A$ allele and other should have at least one $I^B$ . The Whites and The blacks do not fulfil this condition as one of the parents in these two couples have O blood group (ii). The Browns have type A and B blood group and carry at least single copy of $I^A$ and $I^B$ alleles. This makes The Browns potential parents for Baby 4.Thus, the correct answer is option C.