2022 Volume 63 Issue 2 Pages 425-435
Polymerase chain reaction (PCR) is an essential experimental technique in molecular biology and related fields. While the technique is well-known among the general public as a clinical diagnostic method for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), most people may be unaware of the principles and other applications of PCR. In this study, PCR experiments were conducted in an upper secondary school biology class to improve the students’ theoretical and applied knowledge. Conditions for the PCR procedure were as follows: 94°C for 2 minutes, then 25 cycles at 94°C for 20 seconds, 56°C for 20 seconds, and finally 72°C for 20 seconds in three water baths. The target gene was an approximately 1500 bp region of prokaryotic 16S rDNA; the samples were cells and DNA from Bacillus subtilis and natto threads. During the first period, students carried out the PCR process. The students operating the experiment rotated every five reaction cycles, allowing all of them to experience real-life application of PCR. Electrophoresis was undertaken in the second period, and two of the nine groups of students successfully obtained amplicons. The experimental design included infection control measures: all students wore masks, and the classroom was well ventilated during both periods. Prior to the experiment, a survey found that most students were not aware that PCR is a method of DNA amplification. Most knew only that PCR is used to diagnose SARS-CoV-2. A post-class assignment demonstrated that students had successfully understood the principles and applications of PCR.
