Question

The recognition sequence is at times palindromic in nature. Which of the following statements is correct with respect to it?

(a) The molecules which are cut by the same enzyme, anneal only if the sequence is palindromic in nature

(b) When the molecules are cleaved by the same enzyme and the recognition sequence is palindromic in nature, there is no effect on annealing

(c) There are increased chances of annealing if the recognition sequence is palindromic in nature

(d) The term ‘palindromic’ can be used whether the sequence is read from 5’ to 3’ or 3’ to 5’

I had been asked this question during an internship interview.

My question is based upon Restriction Endonuclease & Phosphatases in division Basics of Genetic Engineering of Genetic Engineering

Answer 1

Correct choice is (c) There are increased chances of annealing if the recognition sequence is palindromic in nature

Explanation: The term palindromic can be used only when a sequence is read along the same polarity ie either 5’ to 3’ or 3’ to 5’. When the recognition sequence is palindromic in nature, there are increased chances of annealing because now there are increased orientations. If the sequence is non-palindromic in nature, then also annealing would take place but in fewer orientations.