Question

a. A recombinant vector with a gene of interest inserted within the gene of αgalactosidase enzyme, is introduced into a bacterium. Explain the method that would help in selection of recombinant colonies from non-recombinant ones.

b. Why is this method of selection referred to as “insertional inactivation”?

Answer 1

a. Bacteria is grown in a medium with chromogenic substrate, blue coloured colonies show no recombinations and colonies with no blue colour show presence of recombinants.

b. Gene for the enzyme is inactivated by insertion of foreign DNA.