Genetics & Inheritance MCAT Practice Question
A researcher examines a pedigree showing mitochondrial inheritance of a rare metabolic disorder. An affected mother has children with an unaffected father. The mother's mitochondrial DNA contains a heteroplasmic mutation. Her four children show variable disease severity. Which inheritance pattern and mechanism best explains this variation in severity?
Answer choices
- AAutosomal dominant inheritance with incomplete penetrance
- BX-linked recessive inheritance with skewed X-inactivation
- CMitochondrial inheritance with heteroplasmy and random segregation during cell divisionCorrect answer
- DAutosomal recessive inheritance with variable expressivity
- EGenomic imprinting affecting mitochondrial gene expression
- FMaternal inheritance with nuclear genetic modifiers affecting mitochondrial function
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