How to amplify a gene of interest

Two methods of isolating and amplifying a gene are (a) in vivo, by tricking the replication machinery of a bacterium into amplifying recombinant DNA containing the gene, and (b) in vitro, in the test tube using the polymerase-chain-reaction technique. Both methods employ the basic principles of molecular biology: the ability of specific proteins (red and green) to bind to DNA and the ability of complementary single-stranded nucleic acid segments to hybridize together (the primer used in the test-tube method).