The copying of segments (e.g., genes) within the DNA or RNA molecule. This can be done by man (e.g., polymerase chain reaction), can be caused by certain chemical carcinogens (e.g., phorbol ester), or occur naturally (e.g., in procaryotes and certain lower eucaryotes). The five primary techniques that are used by man to perform gene amplification are: 1) Polymerase Chain Reaction (PCR), 2) Ligase Chain Reaction (LCR), 3) Self-sustained Sequence Replication (SSR), 4) Q-beta Replicase Technique, and 5) Strand Displacement Amplification (SDA).
The duplication of regions of DNA to form multiple copies of a specific portion of the original region. This method of gene enhancement is important in increasing a tumor cell’s resistance to cytotoxic drugs, and in allowing multiple drug resistance to a wide range of unrelated drugs after resistance to a single agent has developed.