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Question #45818
The Question
In a diploid organism, genes A, B, and C are located on the same chromosome. The genetic map distance between A and B is 20 cM, and between B and C is 40 cM. The physical distance between A and C is 60 cM. Which of the following statements is correct regarding the inheritance of genes A and C?
Options
- A.
The observed recombination frequency between A and C will be 60%, indicating they belong to different linkage groups.
- B.
Genes A and C will show a maximum recombination frequency of 50% and assort independently, despite being in the same physical linkage group.
- C.
The recombination frequency between A and C will be exactly 20% due to complete interference by the intermediate gene B.
- D.
Genes A and C will not undergo independent assortment because the principle of independent assortment strictly applies only to genes on non-homologous chromosomes.
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|Recombination Frequency (RF)|Chromosomal Theory of Inheritance
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often conflate 'physical linkage' (being on the same chromosome) with 'statistical linkage' (RF < 50%).
The common misconception is that genes on the same chromosome can never assort independently, and that map distance directly equals RF even beyond 50 cM.
This question tests the threshold dynamics where multiple crossovers mask linkage.
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 |