Pedigree Analysis - Unsolved Practice Set
Chapter: Principles of Inheritance and Variation | Topic: Pedigree Analysis
PEDIGREE ANALYSIS - UNSOLVED PRACTICE SET
Topic: Pedigree Analysis
Multiple Choice Questions
Q1. A pedigree chart is used to:
- Show the geographic distribution of a species
- Trace the inheritance pattern of a particular trait across generations of a family
- Show the DNA sequence of a gene
- Measure blood pressure trends
Q2. In standard pedigree chart symbols, a square generally represents:
- A female
- A male
- An individual of unknown sex
- A mating pair
Q3. In a pedigree chart, a filled (shaded) symbol usually indicates:
- An unaffected individual
- An individual affected by the trait/disorder being studied
- A carrier only, never affected
- A deceased individual only
Q4. Pedigree analysis is particularly useful in humans mainly because:
- Controlled breeding experiments (as in pea plants) cannot be ethically performed on humans
- It replaces the need for any other genetic method
- It only works for plants
- It cannot trace any inherited disorders
Q5. If an X-linked recessive trait appears in a pedigree, it is typically observed:
- Equally in males and females
- More frequently in males than females
- Only in females
- Never in males
Short Answer Questions
Q6. What is a pedigree chart, and why is it a useful tool in human genetics?
Q7. Name the standard symbols used in a pedigree chart for an affected male and an unaffected female.
Q8. Why can't scientists use controlled crosses (like Mendel did with pea plants) to study inheritance patterns in humans?
Q9. How can pedigree analysis help distinguish between a dominant and a recessive trait within a family?
Long Answer Questions
Q10. Describe the standard symbols and conventions used in constructing a human pedigree chart, and explain how it helps trace the inheritance of a trait across generations.
Q11. Explain how pedigree analysis can be used to identify whether a genetic disorder follows an autosomal or X-linked pattern of inheritance.
APPLICATION / ANALYSIS
Q12. A genetic counsellor studies a family's pedigree chart and notices that a particular trait appears in every generation, affecting roughly half the offspring of an affected parent, regardless of sex. Based on this pattern, suggest what type of inheritance (dominant/recessive, autosomal/sex-linked) this trait is likely to follow, and explain your reasoning.
Q13. In a family pedigree, a trait is seen only in males across several generations, always inherited from an affected or carrier mother, and never passed from an affected father to his sons. Using your understanding of pedigree analysis, identify the likely inheritance pattern of this trait, and justify your answer.