Which of the following is not a desirable feature of a cloning vector?
- Presence of origin of replication
- Presence of a marker gene
- Presence of single restriction enzyme site
- Presence of two or more recognition sites
Answer
(4) Presence of two or more recognition sites
Solution
As per NCERT, a cloning vector needs (i) an origin of replication (ori), (ii) a selectable marker gene and (iii) cloning sites.
∵ To link the alien DNA, the vector should have very few, preferably single, recognition sites for the commonly used restriction enzymes.
⇒ Presence of more than one recognition site within the vector generates several fragments, which complicates gene cloning.
∴ Presence of two or more recognition sites is not a desirable feature.
Answer: (4)