β-galactosidase enzyme site is a preferred selectable marker in comparison to antibiotic resistant selectable marker in biotechnology experiments. Justify.

The enzyme β-galactosidase helps in the selection of recombinants.

• It identifies the recombinants from non recombinants by a process called insertional inactivation.

• When a recombinant DNA is inserted in the coding sequence of enzyme β-galactosidase, the enzyme becomes inactive. This is known as insertional inactivation.

• If the plasmid of the bacteria does not have an insert, then the blue color colonies are produced.

• The production of blue colored colonies is due to chromogenic substances.

• If the insert is present in the plasmid, then the enzyme becomes inactive and the colonies produced do not have any color.

• In this way recombinant colonies are separated from non recombinants.

Also, selection of recombinants by inactivation of antibiotics is a very hectic procedure.

Hence, β-galactosidase enzyme site is a preferred selectable marker in comparison to antibiotic resistant selectable marker in biotechnology experiments.