PCR

Definition

A laboratory technique that exponentially amplifies specific DNA sequences using temperature-cycled enzymatic replication, enabling detection, sequencing, or cloning of minute genetic samples.

Etymology

Initialism of polymerase chain reaction, coined by Kary Mullis in 1983.

Example

Molecular taxonomists use PCR to amplify the COI barcode region from a single beetle leg, generating sufficient DNA for species identification without destroying the voucher specimen.

Synonyms

• polymerase chain reaction

Related Terms

• DNA barcoding
• qPCR
• RT-PCR
• primer
• DNA extraction
• molecular systematics
• genotyping
• Sanger sequencing

Usage Notes

In entomological contexts, PCR typically refers to endpoint PCR for amplification, distinct from qPCR (quantitative PCR) which monitors amplification in real time, or RT-PCR (reverse transcription PCR) for RNA targets. The term is sometimes used loosely to include these variants. Specimen preservation method critically affects PCR success: fresh, ethanol-preserved, or dried material generally performs better than pinned specimens with degraded DNA. Non-biological meanings (protein/creatinine ratio, post-consumer recycled, etc.) are irrelevant in natural history contexts.