Methods (molecular, IHC, frozen)
Molecular
PCR
PCR reaction stages
Topic Completed: 1 July 2010
Minor changes: 15 February 2019
Copyright: 2008-2018, PathologyOutlines.com, Inc.
PubMed Search: PCR reaction[TIAB] stages
Table of Contents
Definition / generalCite this page: Shackelford R. PCR reaction stages. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/molecularpathpcrreactionstages.html. Accessed January 18th, 2021.
Definition / general
- Thermocycles in PCR can be divided into three stages
- Understanding where each of these stages occurs in each PCR reaction is important, especially for the analysis of end point PCR reactions
Exponential amplification:
- Initially, all the reagents employed (primers and nucleoside triphophates) in PCR are abundant and the Taq polymerase is fully functional
- Therefore the initial phases of PCR are characterized by near 100% efficient DNA amplification, with the amount of replicated DNA doubled per thermocycle
Leveling off stage:
- In later thermocycles the Taq polymerase begins to lose its activity and the concentration of primers and nucleoside triphophates become rate limiting, hence the reaction rat significantly slows
Plateau:
- Eventually no new DNA amplification occurs due to exhaustion of the reagents and loss of enzyme activity
