explain insertional inactivation used in the selection of recombinants in biotechnology experimentss ?

Insertional inactivation is the loss in function of gene such as antibiotic resistance gene in plasmid due to insertion of foreign DNA/transgene within it. This tool is used to select recombinants. 

Recombinants will die if they are grown on the medium containing the same antibiotic, within the region of which the foreign DNA has been inserted in cloning vector while making recombinant DNA. 

Suppose a plasmid has resistance gene for two antibiotics such as tetracycline and ampicillin. tetR gene on a plasmid has Bam HI recognition site. When BamHI is used for restriction, foreign DNA fragment is inserted within the tetR gene.Hence, tetracycline resistance is not present in those recombinants.

 Recombinants will grow on the media containing ampicillin, but will die on media containing tetracycline. On the other hand, non-recombinants will grow on medium containing ampicillin as well as on medium containing tetracycline.

In this way, insertional inactivation is  used in the selection of recombinants in biotechnology experiments.

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