Mendelian inheritance Practice Questions
20 free Mendelian inheritance 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
20 questions
All Mendelian inheritance questions
- Q1. A healthy couple has a child with an autosomal recessive metabolic disorder. Neither parent is affected. What is the probability that their next child will als…
- Q2. If a father has an X-linked recessive disorder, which of his children are guaranteed to inherit the mutant allele?
- Q3. A woman who is a carrier for an X-linked recessive disease has a child with a healthy male partner. What is the chance that she will have an affected son?
- Q4. A child expresses a phenotype that neither parent shows, but both parents are carriers. Which inheritance pattern best explains this?
- Q5. A mitochondrial disorder is suspected in a family. Which of the following inheritance patterns is expected?
- Q6. A trait shows vertical transmission across generations, and every affected individual has at least one affected parent. Which inheritance pattern does this des…
- Q7. If a homozygous recessive individual mates with a heterozygous carrier, what percentage of their offspring are expected to be affected?
- Q8. A father is affected with an autosomal dominant disorder. The mother is unaffected and does not carry the mutation. What is the chance their child will inherit…
- Q9. A disorder is passed from affected mothers to all children, but affected fathers do not transmit it to any offspring. This pattern most strongly suggests:
- Q10. A patient with an autosomal dominant condition displays variable expressivity. Which best describes this phenomenon?
- Q11. Two unaffected parents have a child with an autosomal recessive disease. What is the probability that their next child will be a carrier?
- Q12. A male has an X-linked dominant disorder. Which of his children are expected to inherit the condition?
- Q13. A lethal autosomal dominant mutation reduces survival before reproduction. What is expected in the population?
- Q14. A pedigree shows affected individuals in every generation, but some individuals who carry the mutant allele do not express the phenotype. This is an example of:
- Q15. In codominance, which statement is true?
- Q16. A child inherits two different mutant alleles of the same gene, one from each parent, resulting in disease expression. What is this called?
- Q17. A woman affected by an autosomal dominant condition has a child with an unaffected man. What is the probability that their child will be unaffected and also a…
- Q18. A pedigree shows only males affected, with no male-to-male transmission. This most likely represents:
- Q19. A mother with an X-linked dominant disorder has a child with an unaffected partner. What proportion of daughters will be affected?
- Q20. A disease shows increasing severity and earlier onset in successive generations. Which genetic concept explains this pattern?