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Question #45315
The Question
A transgenic dicot crop was developed using Agrobacterium-mediated transformation. The wild-type species strictly relies on a genetic outbreeding device to prevent autogamy. However, during GEAC-monitored field trials, researchers observed that the transgenic line unexpectedly produced abundant seeds even when its flowers were bagged before anthesis. Which of the following molecular events best explains this sudden failure of biological containment?
Options
- A.
The transferred vir genes induced the formation of a crown gall that secreted auxins, promoting cleistogamy.
- B.
Insertional mutagenesis by the T-DNA at the S-locus disrupted the expression of self-incompatibility proteins.
- C.
The constitutive promoter of the transgene caused overexpression of S-RNase in the pistil, facilitating self-pollen tube growth.
- D.
The selectable marker gene conferred resistance to the plant's endogenous pollen-recognition glycoproteins.
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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
Agrobacterium Tumefaciens Mechanism|Outbreeding Device Logic|Transgenic Animal Purpose
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: This question requires synthesizing concepts from two different NCERT chapters: 'Biotechnology: Principles and Processes' (T-DNA integration and insertional mutagenesis) and 'Sexual Reproduction in Flowering Plants' (Outbreeding devices/Self-incompatibility).
The trap lies in misunderstanding the random nature of T-DNA insertion, which can inadvertently knock out endogenous genes (like the S-locus), leading to unintended phenotypic changes that violate GEAC biological containment protocols.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Sexual Reproduction in Flowering Plants - Class 12 |
| Concept | Outbreeding Device Logic |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |