Assetion: Insertion of recombinant DNA within the coding sequence of `beta-`galactosidase result n colourless colonies.
Reason : Presence of insert results in inactivation of enzyme `beta-`galactosidase known as insertional inactivation

Options

A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not the correct explanation of A.
C. A is true but R is false.
D. A is false but R is true.

Answer

A

Explanation

z-gene in the lac operon is responsible for the production of beta-galactosidase. Insertion in this sequence of gene will disturb the normal sequence (insertional inactivation) and thus, the cell will lack the enzyme and will result in the formation of colorless colonies on X-Gal (medium)