Question

In the case of blunt-end ligation, blunt ends can be generated by ___________

(a) simply the action of restriction endonuclease which gives straight ends

(b) the polishing of staggered ends

(c) both the action of restriction endonuclease which gives straight ends and polishing of staggered ends

(d) by the action of restriction endonuclease which gives staggered ends

This question was addressed to me during an internship interview.

My question is taken from Categories of Ligation Reaction in chapter Basics of Genetic Engineering of Genetic Engineering

Answer 1

Correct answer is (c) both the action of restriction endonuclease which gives straight ends and polishing of staggered ends

Explanation: Blunt ends are those which don’t have single stranded ends as overhangs. The ends are double stranded. And these can be generated by polishing the staggered ends or the action of restriction endonuclease which generate straight ends.