Question

What happens if insert DNA is cut with two different restriction enzymes at the ends?

(a) It is difficult to insert the fragment

(b) The insert can be ligated in any orientation

(c) The insert can be ligated in one orientation only

(d) The amount of product increases

The question was posed to me during an interview.

This intriguing question comes from Modifications in Cloning Methods, Linkers,  Adaptors and Cassettes in portion Simple Cloning of Genetic Engineering

Answer 1

The correct option is (c) The insert can be ligated in one orientation only

To explain: If the DNA is cut with two different enzymes at the ends, it is possible to ligate the fragment in only one orientation. It is so because each end would have a unique sequence to ligate.