Question

There is a limit on upper size of the DNA to be packed. Choose the correct statement with respect to phages in this context.

(a) There is some phage DNA lost in this process

(b) The phages are known as transformed phages

(c) These type of phages can’t be selected and harvested

(d) Lambda is not a special attachment site

This question was addressed to me in an online interview.

The query is from Cloning in Lambda in chapter Other Vector Systems for E of Genetic Engineering

Answer 1

Right answer is (a) There is some phage DNA lost in this process

To explain: There is a limit on the upper size of the DNA to be packed. If the significant amount of sequence is flanked by the phage particles, there are chances of losing some phage DNA. These phages are known as transducing phages and can be easily selected and harvested for the lost DNA. Lambda is having a special site for attachment in E. coli.