Both parents are heterozygous for the blood group allele AO (i.e., genotype AO). What is the probability that their child will have blood group O? Express your answer as a fraction.
Answer
1/4
The correct answer is 1/4 — Therefore, the probability is 1/4.
Step-by-step solution
- Write the possible gametes from each parent: A and O.
- Set up a Punnett square with the two gametes from each parent.
- Identify the genotype combinations: AA, AO, OA, OO.
- Count the occurrence of genotype OO, which gives blood group O; it appears in 1 out of 4 squares.
- Therefore, the probability is 1/4.
Common mistake: Multiplying the probabilities of two A alleles instead of focusing on O alleles
Concept tested: Mendelian inheritance of blood groups
Published · How this solution was prepared and checked
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