Pedigrees Transitional Reasoning Practice

Questions

1. 1.

   A clinical geneticist analyzes a three-generation pedigree tracking a rare metabolic condition affecting cellular respiration. In this family, every child born to an affected mother inherits the condition, whereas no children born to affected fathers and unaffected mothers develop it. A couple in the third generation consists of an affected male and an unaffected female who are planning to have their first child. Based on the non-Mendelian inheritance pattern established by this pedigree, what is the probability that their child will inherit the condition, and which mechanism explains this outcome?

   • A) 50%, because the trait exhibits autosomal dominant inheritance and the affected father transmits the mutant allele to half of his gametes.
   • B) 0%, because the trait exhibits mitochondrial inheritance and is transmitted exclusively through the cytoplasm of the maternal egg cell.
   • C) 100% for sons and 0% for daughters, because the trait is Y-linked and passes directly from father to male offspring.
   • D) 100% for daughters and 0% for sons, because the trait exhibits X-linked dominant inheritance from the father.

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