Plasmid integration & Host transformation

    Exposure of antibiotic-sensitive E. coli cells to a recombinant plasmid allows integration of the plasmid DNA into the bacterial DNA (transformation).  The bacterial cells can then express the genes found in the plasmid, which in a cloning experiment include those for resistance to antibiotics. Growth of individual bacterial colonies on media with antibiotics then indicates cells that have successfully integrated plasmid DNA along with the cloned insert DNA.