ABSTRACT
Polymerase chain reaction (PCR) was developed into a practical laboratory technique during the 1980s by researchers at the Cetus Corporation in Berkeley, California, though a concept for the method was sketched by K. Kleppe et al. a decade earlier. A PCR experiment begins when the researcher pipets the PCR reagents into 0.2 mL plastic reaction tubes. PCR gels can have many different appearances depending on the nature of the PCR or electrophoresis problems and they can therefore reveal important clues for troubleshooting problems. A positive PCR control is optional—provided the PCRs have been working as expected, this control can nonetheless be useful if the sample tubes show little or no sign of amplification. PCR is invaluable because it enables researchers to easily and inexpensively generate sufficient amounts of target DNA templates for use by DNA sequencing methods.
