Question

Mention the role of selectable marker in cloning vector with an example.

Answer 1

Answer

• The selection of recombinants due to inactivation of antibiotic resistance gene is a tedious procedure.

• It requires simultaneous plating on two plates having different antibiotics.

• Therefore, alternative selectable marker is developed to differentiate recombinants and no recombinants on the basis of their ability to produce colour.

• It is done in the presence of a chromogenic substrate.

• In this process, a recombinant DNA is inserted in the coding sequence of an enzyme beta-galactosidase.

• This causes inactivation of the enzyme.