This figure shows the insertion of a piece of foreign DNA into a plasmid.  A plasmid is selected that has a gene for antibiotic resistance (in our case, kanamycin).  The plasmid and DNA of interest are both cut with the same restriction enzyme.  They are mixed together, and the DNA strands join by base pairing.  DNA ligase is added, and the strands bond covalently.  This results in a mixture of desired recombinant plasmids and mismatches.  The desired plasmid (and other DNA) is then inserted into the cells by transformation.  The cells are plated onto medium containing a particular antibiotic.  The desired cells are identified by their resistance to the antibiotic.  (Campbell, 1996, p. 372-374)

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