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Question #45825
The Question
In a theoretical genetic analysis of a 47, XXY individual (Klinefelter syndrome) undergoing meiosis, the recombination frequency between two X-linked genes deviates significantly from the standard linkage map established in normal 46, XX females. Which of the following cytological events best explains this deviation?
Options
- A.
The formation of trivalent or bivalent-univalent configurations during the pachytene stage disrupts standard crossover interference.
- B.
The extra X chromosome undergoes obligate heterochromatization into a Barr body during prophase I, preventing any synapsis.
- C.
The SRY gene on the Y chromosome produces a transcription factor that prematurely dissolves the synaptonemal complex during zygotene.
- D.
Crossing over is completely suppressed because the Y chromosome entirely lacks homologous regions with the X chromosome.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Recombination Frequency|Sex-Linked Recessive Inheritance|Down/Klinefelter/Turner Syndrome Karyotypes
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Linking chromosomal aneuploidy (Klinefelter syndrome) with its mechanical consequences during meiotic Prophase I.
The primary trap (Option B) exploits the student's knowledge of Barr bodies in XXY individuals, confusing somatic X-inactivation with meiotic germ-cell pairing dynamics.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Principles of Inheritance and Variation - Class 12 |
| Concept | Recombination Frequency (RF) |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |