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Question #45822
The Question
In a genetic mapping experiment, two genes 'A' and 'B' are known to be physically separated by a large distance on the same chromosome. However, a test cross of a specific dihybrid individual (AaBb) yields an observed recombination frequency of 0%, mimicking absolute linkage. Which of the following structural chromosomal aberrations in the heterozygous state best explains this phenomenon?
Options
- A.
Interstitial deletion between loci A and B
- B.
Chromosomal inversion encompassing loci A and B
- C.
Reciprocal translocation involving the chromosome segment
- D.
Tandem duplication of the intervening gene sequences
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|Mendelian Dihybrid Exceptions|Linked Genes
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Distinguishing between the physical occurrence of crossing over and the viability of recombinant gametes.
Students often mistakenly equate 0% RF exclusively with physical proximity (absolute linkage).
The trap lies in ignoring how structural aberrations like inversions act as 'crossover suppressors' by eliminating recombinant progeny, thereby violating the standard Mendelian distance-to-RF correlation.
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 |