Question Detail
Question
How many genotypes are produced by the 4 human blood groups: A, B, AB and O?
Correct Answer
Option B is the correct answer.
Detailed Explanation
The ABO blood group is determined by a single gene with three alleles: I^A, I^B, and i. I^A and I^B are codominant, and both are dominant over i. The possible genotypes are: I^A I^A, I^A i (both giving blood type A), I^B I^B, I^B i (both giving blood type B), I^A I^B (giving blood type AB), and i i (giving blood type O). That's a total of 6 distinct genotypes.
Hint
List all possible combinations of the three alleles.