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Question #47713
The Question
Gene therapy aims to correct genetic defects by delivering functional genes into an individual's cells. Which of the following statements regarding the vectors and strategies used in gene therapy is INCORRECT?
Options
- A.
In ADA deficiency, periodic infusion of genetically engineered lymphocytes is required because these somatic cells are not immortal.
- B.
Retroviral vectors efficiently integrate into the host genome but carry the clinical risk of insertional mutagenesis if they integrate near a proto-oncogene.
- C.
Unlike retroviral vectors, plasmid vectors used in germline interventions ensure stable, multi-generational expression because extrachromosomal DNA is immune to epigenetic silencing.
- D.
Introducing a functional gene into cells at early embryonic stages can provide a permanent cure, but this constitutes heritable germline therapy.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Evolutionary_Exception
Tackle problems where standard rules evolve or change based on specific environmental constraints.
Concepts Behind This Question
DNA Ligase Polarity|Plasmid vs Chromosomal DNA|Restriction Enzyme Cleavage Physics
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often confuse the 'safety' of plasmids (non-integrating, hence avoiding insertional mutagenesis) with 'long-term efficacy'.
The trap assumes that because plasmids are safer than retroviruses, they must be ideal for permanent germline therapy.
In reality, their lack of integration leads to transient expression, and extrachromosomal DNA is heavily targeted by cellular epigenetic silencing mechanisms like methylation.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology : Principles and Processes - Class 12 |
| Concept | DNA Ligase Polarity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |