Question: 179: Which of the following is not a desirable feature of a cloning vector?
(1) Presence of single restriction enzyme site
(2) Presence of two or more recognition sites
(3) Presence of origin of replication
(4) Presence of a marker gene
Answer: Option (2)
Explanation:
A cloning vector is a DNA molecule used to transfer foreign DNA into a host cell for replication.
A desirable cloning vector should have a single restriction enzyme site so that insertion of foreign DNA occurs at a specific location.
If a vector has two or more recognition sites for the same restriction enzyme,
it may get cut into multiple fragments, making cloning difficult.
An origin of replication is essential so that the vector can replicate inside the host cell.
A marker gene is required to identify and select the transformed host cells.
Therefore, the presence of two or more recognition sites is not a desirable feature of a cloning vector.