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Question #45851
The Question
Which of the following statements regarding the inheritance and expression of X-linked recessive disorders (e.g., Haemophilia) in individuals with sex chromosomal aneuploidies is CORRECT?
Options
- A.
A male with Klinefelter syndrome (47, XXY) is hemizygous for X-linked genes and will express the disorder with a single recessive allele.
- B.
A female with Turner syndrome (45, X0) possesses one Barr body and requires two recessive alleles to phenotypically express the disorder.
- C.
A male with Klinefelter syndrome (47, XXY) can be an asymptomatic carrier for the disorder, a genetic state impossible in normal males.
- D.
The population incidence of X-linked recessive disorders in Turner syndrome females is identical to that of normal females.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Down/Klinefelter/Turner Syndrome Karyotypes|Sex-Linked Recessive Inheritance
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Genotype-Phenotype Coupling in Aneuploidy.
Students often rigidly memorize 'males cannot be carriers for X-linked traits' and 'females require two recessive alleles' without adjusting for the altered chromosome count in aneuploidies.
By applying hemizygosity rules to 47, XXY and 45, X0, the student must deduce that an XXY male behaves like an XX female regarding X-linked carrier status, while an X0 female behaves like an XY male.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Principles of Inheritance and Variation - Class 12 |
| Concept | Down/Klinefelter/Turner Syndrome Karyotypes |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |