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Question #45257
The Question
A geneticist is evaluating two different gene therapy approaches for a severe monogenic disorder. Approach X involves introducing a functional therapeutic allele into the patient's hematopoietic stem cells via a retroviral vector. Approach Y involves the microinjection of the therapeutic allele directly into a fertilized ovum. Which of the following statements is INCORRECT regarding the cellular and genetic consequences of these approaches?
Options
- A.
Approach Y ensures that the therapeutic allele undergoes DNA replication during the S-phase of every subsequent mitotic division, permanently altering the organism's systemic DNA content.
- B.
Approach X is an example of somatic gene therapy, meaning the modified DNA content is restricted to specific tissue lineages and will not participate in gametogenesis.
- C.
In Approach Y, the genetic modification alters the hereditary potential of the organism, allowing the therapeutic allele to be transmitted to future generations.
- D.
Because Approach X utilizes multipotent stem cells, the therapeutic allele will eventually be incorporated into the germinal epithelium, providing a permanent heritable cure for the patient's offspring.
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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
Gene Therapy|DNA Replication|Transgenic Animal Purpose
Why This Question Is Tricky
Common Mistakes
The 'Conceptual Pivot' is the distinction between multipotent somatic stem cells (like hematopoietic stem cells) and totipotent zygotic cells.
A common misconception among students is confusing 'stem cell therapy' with 'germline therapy'.
Students often assume that because stem cells divide continuously and differentiate, they can pass genetic changes to the next generation.
However, somatic stem cells are lineage-restricted and do not cross over to form the germline, which segregates very early in embryonic development.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Cell Cycle and Cell Division - Class 11 |
| Concept | DNA vs Chromosome Content |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |