What is Polymerase Chain Reaction (PCR)?

Polymerase Chain Reaction (PCR) is a method used to amplify a single or few copies of DNA quickly and accurately. It is a technique used to make millions of copies of a specific DNA sequence. PCR has revolutionized biology, as it allows researchers to study a wide variety of topics from ancient DNA to cancer.

How Does PCR Work?

PCR works by using heat to separate the two strands of a DNA molecule. Then, special enzymes called polymerases are used to make copies of each strand. This process is repeated over and over until millions of copies are made. The PCR process is usually done in a thermocycler, which is a machine that can rapidly increase and decrease temperature.

What Are the Uses of PCR?

PCR is used in a variety of fields, including forensics, biotechnology, and medicine. It can be used to detect genetic diseases, identify bacteria and viruses, and diagnose cancer. PCR can also be used to detect gene mutations, determine paternity, and study ancient DNA.

Examples of PCR

  • Diagnosing Diseases: PCR can be used to detect the presence of specific viruses or bacteria in a sample. This is important for diagnosing diseases such as HIV and tuberculosis.
  • Forensic Science: PCR can be used to identify individuals by comparing their DNA to that of a crime scene. This is used in criminal investigations and can help solve cold cases.
  • Gene Mapping: PCR can be used to study the sequence of a gene, which can be used to identify mutations or other genetic abnormalities.


PCR is a powerful and versatile tool that can be used to study a wide range of topics. It is used in forensics, medicine, and biotechnology to diagnose diseases, study gene mutations, and identify individuals.