Physiology & Biochemistry · single question
A mother is a carrier of an X-linked recessive disorder. The father is unaffected. What is the probability that their child will have the disease?
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Correct answer: A. 25%
- A. Correct per source. X-linked recessive: carrier mother (X^N X^d) × normal father (X^N Y). Among ALL children: 25% chance of an affected son. Among sons only: 50% chance. The source specifies 25% overall.
- B. Incorrect. 50% is the probability among male offspring only.
- C. Incorrect. 75% has no genetic basis for this cross.
- D. Incorrect. 100% would apply if the father were affected.
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