PCR procedure - OPERON

Polymerase chain reaction (PCR) is a technique used in molecular biology to amplify a few copies of a segment of of a particular DNA sequence to thousands or millions of copies of this sequence.
It is an easy, cheap, and reliable which is applicable to numerous fields in modern biology and related sciences. Typically, the goal of PCR is to make enough of the target DNA region that it can be analyzed or used in some other way. For instance, DNA amplified by PCR (amplicons) may be sent for sequencing, visualized by gel electrophoresis or hybridization, or cloned into a plasmid for further experiments.
PCR can be performed using source DNA from a variety of tissues and organisms, including peripheral blood, skin, hair, saliva, and microbes. Only trace amounts of DNA are needed for PCR to generate enough copies to be analyzed using conventional laboratory methods. For this reason, PCR is a very sensitive assay, so it is extremely important to keep good laboratory practices, specially regarding hygiene, order and security in any of the stages of the technique (nucleic acid extraction, preparation of the reactions and detection of the amplified ones), in order to avoid possible contaminations that could affect the results of the test.
To minimize this problem there are certain conditions that must be controlled, such as:
-Separate contaminated work areas with amplicons from those areas free of them.
-Independent sets of equipment that should not be shared between areas (micropipettes, racks, gowns, gloves, marker pens, microtubes, centrifuges, refrigerators, etc.).
-Maintenance of a unidirectional work flow from the cleanest areas to the dirtiest.
-Air flows with positive and negative pressures according to the area.
-Use of PCR-quality materials (micropipette tips, microtubes, etc.), free of exogenous DNA, DNAses and RNAases.
-Use micropipette filter tips to reduce the risk of aerosol formation.
-Clean the surface used to prepare the PCR reactions with ethanol (70%) and, if possible, decontaminated with ultraviolet radiation before and after each preparation (15-30 min).
The video shows an example of how a PCR should be prepared correctly, showing the different zones for the different activities.

[@gagantalwar4551]

Why pcr is run in a unidirectional flow??

[@operones]

Hi! Workflow must be unidirectional to ensure that neither samples nor amplificated products are contaminated from contaminated areas. In fact, dedicated laboratory coats should be supplied for each area and gloves should be changed between areas.