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Question #45820
The Question
A linkage group comprises all the genes present on a single type of chromosome. In humans, non-disjunction during meiosis can lead to aneuploidy, altering the total chromosome number. Which of the following correctly identifies the number of linkage groups in a female with Turner's syndrome (45, XO), a male with Down's syndrome (47, XY, +21), and a normal human male (46, XY), respectively?
Options
- A.
22, 24, 24
- B.
23, 24, 24
- C.
23, 25, 24
- D.
22, 25, 23
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
Linkage Group Calculation|Down/Klinefelter/Turner Syndrome Karyotypes|Chromosomal Theory of Inheritance
Why This Question Is Tricky
Common Mistakes
The 'Conceptual Pivot' is distinguishing between the total number of chromosomes and the number of 'unique' chromosome types (linkage groups).
Students often fall into the Quantitative Trap of assuming that monosomy (45, XO) reduces the linkage group count to 22, or that trisomy (47, +21) increases it to 25.
Furthermore, they frequently forget that normal males have 24 linkage groups (22 autosomes + X + Y) compared to normal females who have 23 (22 autosomes + X).
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Principles of Inheritance and Variation - Class 12 |
| Concept | Linkage Group Calculation |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |