Question

Which of the following is used for blocking the phage-encoded recombination?

(a) Mutation in D gene

(b) Mutation in E gene

(c) Red mutation

(d) Mutation in S gene

The question was posed to me in a national level competition.

My question comes from Cloning in Lambda topic in division Other Vector Systems for E of Genetic Engineering

Answer 1

The correct choice is (c) Red mutation

For explanation: Red mutation is used for blocking the phage-encoded recombination. It ensures that no recombination or rearrangement takes place while carrying out packaging in vitro.