Introduction
The polymerase chain reaction is the most widely used method for in vitro DNA amplification for purposes of molecular biology and biomedical research. This process involves the separation of the double-stranded DNA in high heat into single strands (the denaturation step, typically achieved at 95–97 °C), annealing of the primers to the single stranded DNA (the annealing step) and copying the single strands to create new double-stranded DNA (the extension step that requires the DNA polymerase)requires the reaction to be done in a thermal cycler. These bench-top machines are large, expensive and costly to run and maintain, limiting the potential applications of DNA amplification in situations outside the laboratory (e.g., in the identification of potentially hazardous micro-organisms at the scene of investigation, or at the point of care of a patient). In vivo, DNA is replicated by DNA polymerases with various accessory proteins, including a DNA helicase that acts to separate the DNA by unwinding the DNA double helix. HDA was developed from this concept, using a helicase (an enzyme) to denature the DNA.
Read more about this topic: Helicase-dependent Amplification
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