Q.5 Choose the option that lists the correct sequence of steps involved in gene therapy.
P. Injection of expression vector into patient
Q. Wild-type gene is inserted into expression vector
R. Wild-type gene is isolated and cloned
S. Wild-type gene is transcribed and translated in the patient
(A) Q, S, P, R
(B) Q, P, R, S
(C) R, P, Q, S
(D) R, Q, P, S

The correct answer is (D) R, Q, P, S.​

Gene therapy introduces a functional wild-type gene to correct genetic defects, following a precise sequence of molecular biology steps. This matches the standard protocol where isolation precedes vector preparation and delivery, culminating in gene expression inside the patient.​

Step Breakdown

Gene therapy begins with obtaining the therapeutic gene and ends with its functional expression.

• R: Wild-type gene is isolated and cloned – The normal gene is first extracted from a source (often via PCR or restriction enzymes) and amplified in a host like bacteria to produce multiple copies.​

• Q: Wild-type gene is inserted into expression vector – The cloned gene integrates into a plasmid or viral vector (e.g., AAV or retrovirus) equipped with promoters for controlled expression.​

• P: Injection of expression vector into patient – The recombinant vector delivers the gene directly (in vivo) or via modified patient cells (ex vivo), targeting affected tissues.​

• S: Wild-type gene is transcribed and translated in the patient – Once inside cells, the gene uses host machinery for mRNA production and protein synthesis, restoring function.​

Option Analysis

Each choice fails except D due to incorrect order.

Gene therapy steps sequence forms the backbone of modern biotechnology treatments for genetic disorders. This gene therapy steps sequence—starting with wild-type gene isolation and ending in patient expression—powers therapies like those for SCID or muscular dystrophy.​

Core Gene Therapy Process

The gene therapy steps sequence follows recombinant DNA technology.

• Isolate and clone the wild-type gene (R) using PCR or libraries.​

• Insert into an expression vector (Q) like AAV for delivery.​

• Inject the vector into the patient (P) via in vivo or ex vivo methods.​

• Achieve transcription and translation (S) for therapeutic protein.​

This correct sequence of steps in gene therapy ensures safe, effective gene correction.​

CSIR NET MCQ Insights

For exams like CSIR NET Life Sciences, recognize distractors in options like Q-S-P-R, which disrupt molecular logic. The right gene therapy procedure sequence (R-Q-P-S) appears in standard texts.​