Two unaffected parents have a child with an autosomal recessive condition. Which statement is correct?
Answer and explanation
Correct answer: A. Both parents must be carriers, with a genotype of Aa
- Step 1: The affected child has genotype aa, so received an a allele from each parent.
- Step 2: The parents show the dominant phenotype, so each must be Aa.
Answer
both parents are carriers.
Why not the others: AA parents cannot pass on a; neither parent is affected; an X-linked recessive trait is a different pattern.
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