Question

Methylation dependent restriction system (MDRS) are included in which class of restriction enzymes?

(a) Type I

(b) Type II

(c) Type III

(d) They are the product of mcrA, mcrB or mrr loci

This question was addressed to me by my school principal while I was bunking the class.

This interesting question is from Transformation and Hosts topic in section Simple Cloning of Genetic Engineering

Answer 1

The correct choice is (d) They are the product of mcrA, mcrB or mrr loci

To explain I would say: MDRS don’t come under the general classification of type I-III. They are the product of mcrA, mcrB and mrr loci. It would degrade DNA containing methylcytosine (mcrA, mcrB) or methyladenine (mrr).