14. 1 dna cloning: main sources of dna sequences, extracted from the genome of the cell, synthesized from an mrna template by reverse transcriptase. In laboratory by machines: dna cloning: produces many copies of a given piece of dna (gene of interest for study, bacteria, cut dna fragments -> one containing gene of interest. Inserted into plasmid: produce separate recombinant dna molecule. Introduced to bacteria: each bacteria gets a different plasmid, bacterium continues to divide. 14. 1c dna libraries contain collections of cloned dna fragments: complementary dna (cdna): dna molecule complementary to an mrna molecule made by reverse transcriptase. 14. 1d the polymerase chain reaction amplifies dna in vitro: polymerase chain reaction (pcr): produces an extremely large number of copies of a specific. 14. 2c genetic engineering uses dna technologies to alter the genes of a cell or organism: transgenic: modified to contain genetic information from an external source, genetic engineering of bacteria to produce proteins, gene for the protein is cloned.