Reporter enzyme can differentiate recombinants from non-recombinants on the basis of their ability to produce specific color in the presence of chromogenic substrate. ArDNA is inserted within the coding sequence of the enzyme, galactosidase.
This results into inactivation f the enzyme which is referred to as insertional inactivation. The presence of a chromogenic substrate gives blue colored colonies, if the plasmid in the bacteria does not have an insert.
Presence of insert results into insertional inactivation of the-galactosidase and the colonies do not produce any colour. These are identified as recombinant colonies.
