The Polymerase Chain Reaction (PCR) is a laboratory technique specifically designed to amplify targeted DNA sequences exponentially. It uses a cyclic process of denaturation, annealing of primers, and extension by DNA polymerase to create millions of copies of a specific DNA region. This amplification allows for detection and analysis of tiny amounts of DNA, which is crucial in diagnostics, forensic science, and genetic research. Unlike gel electrophoresis, Western blot, or ELISA, PCR uniquely increases DNA quantity rather than just separating or detecting molecules.

Reference: Molecular Biology of the Cell, Alberts et al., 6th Edition.