Question

There are various methods to distinguish whether a colony contains a recombinant or not. One such method is __________

(a) blue white screening

(b) checking whether replication is taking place or not

(c) checking the number of copies

(d) looking for the multiple cloning site

This question was addressed to me in an internship interview.

My enquiry is from Modifications in Cloning Methods, Linkers,  Adaptors and Cassettes in portion Simple Cloning of Genetic Engineering

Answer 1

The correct option is (a) blue white screening

The explanation: Blue white screening is a method to know whether a colony is having a recombinant or not. It is also known as alpha complementation method. It is based on the lacZ operon. If there is an insert, the colonies are white in colour and if there is no insert, the colonies are blue in colour.