Insertional inactivation

a technique of recombinant DNA technology used to select bacteria that carry recombinant plasmids

Definition
Insertional inactivation occurs when a fragment of foreign DNA is inserted into a restriction site within a gene, thus disrupting its open reading frame and (though this might not necessarily follow) its function. Insertional inactivation of a conditionally toxic gene indicates surviving bacterial colonies as recombinant, but might also remove recombinant colonies whose inactivation is only partial (leaky). Insertional activation of a gene encoding a color reaction subsequently allows selection of recombinant clones by visual inspection (with fainter staining of leaky clones).