What is insertional inactivation?

Explanation

If a recombinant DNA is inserted within the coding sequence of enzyme B-galactosidase, it results in the inactivation of the enzyme which is referred to as "insertion a] inactivation". The presence of chromogenic substrate gives blue coloured colonies if the plasmid in the bacteria does not have an insert presence of insert results in insertional inactivation and the colonies do not produce any colour.