Question

Given below are two statements, one is labelled as Assertion (A) and other one labelled as Reason (R).
Assertion (A): Shuttle vector can be propagated in cells of two or more species.
Reason (R): Shuttle vector contain multiple replication of origin and other elements that allows them to be used in more than one species.
Choose the correct answer from the options given below:

• A. Both (A) and (R) are true and (R) is the correct explanation of (A).
• B. Both (A) and (R) are true but (R) is NOT the correct explanation of (A).
• C. (A) is true but (R) is false.
• D. (A) is false but (R) is true.

Hint:

Think of a shuttle vector as a plug-and-play device with two power plugs: It has one replication system for cloning and preparation in E. coli, and a second system for functional testing in yeast or mammalian cells.

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
A shuttle vector is a specialized hybrid plasmid vector designed to replicate and be selected in different host organisms (e.g., both prokaryotic and eukaryotic hosts).

Step 2: Detailed Explanation:
- Assertion Analysis: Shuttle vectors can move, or "shuttle," cloned genes between different host species, such as E. coli and yeast (S. cerevisiae), allowing propagation in both systems. Thus, the Assertion is true.
- Reason Analysis: To replicate in two different organisms, a shuttle vector must carry two different origins of replication (e.g., ori for E. coli and ARS for yeast) and distinct selectable markers compatible with each host's translational machinery. This makes the Reason true.
- Since the presence of these dual replication origins and selectability components is exactly what enables the vector to propagate in multiple species, (R) is the correct explanation of (A).

Step 3: Final Answer:
Both (A) and (R) are true, and (R) is the correct explanation of (A).