Polymerase Chain Reaction (PCR)

Definition

A laboratory technique that rapidly makes millions of copies of a specific DNA segment, allowing tiny amounts of genetic material to be amplified for study or detection.

Key points

• PCR repeatedly cycles through three steps: denaturation (heating to separate the DNA strands), annealing (short primers attach to the target), and extension (the enzyme DNA polymerase builds new strands).
• It uses a heat-stable enzyme, Taq polymerase, originally from a bacterium living in hot springs, which survives the high temperatures of each cycle.
• The method was developed by Kary Mullis, who won the 1993 Nobel Prize in Chemistry.
• RT-PCR (reverse transcription PCR) first converts RNA into DNA and is the standard confirmatory test for viruses such as the one causing COVID-19.
• Applications include disease diagnosis, DNA fingerprinting in forensics, paternity testing, and detecting genetic disorders.

Why it matters for CAPF

PCR and RT-PCR (COVID-19 testing), DNA amplification, Taq polymerase, and forensic DNA work are recurring biotechnology facts with a clear policing and crime-investigation link.

Common confusion

PCR amplifies (copies) DNA; it does not edit DNA like CRISPR. RT-PCR is used for RNA viruses because it first makes a DNA copy of the RNA; ordinary PCR works directly on DNA. PCR is a diagnostic and copying tool, not a treatment.

Related concepts

concept dna and rna, concept crispr, concept monoclonal antibodies

Parent note

biotechnology and genetics