Pedigree analysis Practice Questions
19 free Pedigree analysis practice questions for the USMLE Step 1, each with the correct answer and a detailed explanation. Open any question below, or take the full set as an interactive quiz.
Questions
19 questions
All Pedigree analysis questions
- Q1. In a pedigree chart, a filled square usually represents what?
- Q2. Which mode of inheritance is most consistent with a trait that appears in every generation and affects both sexes equally?
- Q3. If two unaffected parents have an affected child, which mode of inheritance is most likely?
- Q4. In a pedigree for an X-linked recessive disease, which of the following patterns is most suggestive?
- Q5. Which clue argues against X-linked dominant inheritance in a pedigree?
- Q6. Which assumption is typically made when performing classic pedigree analysis under Mendelian inheritance models?
- Q7. In autosomal dominant inheritance with full penetrance, what is the probability a child will be affected if one parent is heterozygous (Aa) and the other is ho…
- Q8. In a pedigree, if an affected father transmits the trait to all his daughters but none of his sons, which inheritance pattern is most likely?
- Q9. Which inheritance pattern would you suspect if multiple siblings are affected but neither parent shows the trait and there is consanguinity?
- Q10. Which mode of inheritance is nearly ruled out if affected males are found in consecutive generations and pass the trait to their sons?
- Q11. Which scenario describes pseudodominance that might mislead a pedigree analyst?
- Q12. In pedigree analysis, which of the following features strongly suggests an autosomal recessive rather than autosomal dominant inheritance for a rare disorder?
- Q13. Which pattern on a pedigree might suggest mitochondrial inheritance?
- Q14. If a pedigree shows an affected male whose mother is unaffected but paternal grandfather is affected, which inheritance pattern is least likely?
- Q15. When analyzing a pedigree, why do geneticists often assume “complete penetrance” and “rare allele frequency” for a Mendelian trait?
- Q16. A pedigree shows only males affected in multiple generations, and no daughters are affected even when fathers are affected. Which pattern is the best fit?
- Q17. Which inheritance pattern would you suspect if all children — male and female — of an affected male are affected?
- Q18. Which feature on a pedigree would argue for autosomal rather than X-linked inheritance when both sexes show roughly equal affected frequency?
- Q19. In pedigree analysis with a rare autosomal recessive trait, what is the chance that two carrier parents will have an unaffected child who is also a carrier?