Looking for ideas to teach PCR in the classroom? Polymerase Chain Reaction (PCR) is a cornerstone technique in molecular biology, with applications from medical diagnostics to environmental monitoring.
Introducing PCR to high school or undergraduate students is a great way to demonstrate key techniques in genetics and molecular biology. It also encourages critical thinking and hands-on problem-solving.
But teaching PCR comes with challenges, starting with “What do you teach?” and “How do you teach it?” How can you give students an experience that’s both intuitive and relevant?
We’ve highlighted four of our favorite open-access PCR practicals — published examples exploring topics in human biology, plant sciences, and marine sciences.
These practicals are safe, simple, and designed for classroom use. They fit easily into undergraduate curricula, and can be used as-is, adapted, or used as inspiration for your own classes.
We’re grateful to the original authors for these fantastic open-access resources, and hope you find them useful too!
Want to save this for later? Get the PDF guide.
1. Determination of Rhesus factor blood types
Why is my blood type positive or negative?
This practical is a great hands-on introduction to PCR for students in human biology or medical sciences. Students investigate their Rhesus factor blood group by detecting a gene fragment linked to Rh-positive status. The protocols are based on over a decade of successful classes at the Universitat de Barcelona in Spain.
Proposed schedule
- Lecture: An introduction to DNA structure and PCR theory
- Lab Sessions: Two blocks (3 hours each)
- Teacher Evaluation: Lab behavior record, a notebook report, and a 20-question quiz
- Optional Reading: A list of recommended resources to deepen understanding
Why we like this practical
What makes this activity unique? It’s not just hands-on lab work — there is a personal connection. By exploring their own genetics, students become fully invested in the process, while developing essential molecular biology and PCR skills by exploring their own genetics.
The focus on Rhesus blood types provides a link to broader topics in genetics, medicine and real-world diagnostics. Using human samples also allows discussions about consent and research ethics, which are crucial in medical research.
Student activities
| 1 | DNA extraction from cheek cells using a saline mouthwash and proteinase K |
| 2 | PCR using primers targeting the human Rh locus to determine Rh blood group types |
| 3 | Agarose gel electrophoresis to examine PCR products |
2. Genetic basis of color in red and white onions
Why are onions different colors?
This laboratory practical is a brilliant choice for courses covering plants or biosynthetic pathways. Students explore the genetics of pigmentation in red and white onions by screening four pigmentation-related genes to identify a non-functional one. The activity is designed for groups of four, encouraging teamwork and collaboration across the class.
Proposed schedule
- Lab Sessions: Two blocks (2-3 hours each)
Why we like this practical
This activity shows how PCR can go beyond providing a simple positive or negative result. Here PCR is used to systematically investigate different gene regions, and explore the functioning of a biosynthetic pathway. It involves a familiar subject (onions); an interesting biological question (why are onions different colors?); and provides a very visual result. Students can “see” the difference at the DNA level between red and white onions.
It provides an excellent foundation for exploring broader topics such as genotype-phenotype interactions, gene-enzyme relationships, physiology, and genetic diversity. The authors also suggest extending the activity with additional investigations, like sequencing full-length genes, analyzing the genes with bioinformatics tools, or even exploring gene expression in plant organs using reverse transcriptase PCR!
Student activities
| 1 | DNA extraction from onion tissue (several methods are suggested) |
| 2 | PCR using primers targeting the human Rh locus to determine Rh blood group types |
| 3 | Agarose gel electrophoresis to examine 4 PCR products |
3. Identifying commercial fish using PCR
What species is this fish?
This practical is a great choice for courses in marine biology, fisheries science, or conservation genetics. In this activity, students apply molecular techniques to identify and trace commercial fish species. It act as a nice introduction to more advanced techniques, like DNA barcoding.
Proposed schedule
- Lab Sessions: Three blocks (2 hours each)
- Computer practicals: Two sessions (2 hours and 1 hour)
- Results discussion: Interpretation and discussion of results (1 hour)
Why we like this practical
This lab shows just how powerful PCR and gel electrophoresis can be for identifying different species, all while tackling a real-world issue: the mislabelling of commercial fish. The best part? Students get to work with store-bought fish or fish products, and there’s even a chance they might uncover actual cases of mislabelled fish! It’s hands-on science with a dash of mystery.
The computer classes offer a simple introduction to searching for gene sequences and predicting fragment lengths for the target species. Along the way, students can also learn about coding and non-coding DNA, gene structure, and genome organization. No special bioinformatics software or expertise is needed — everything is done using easy-to-use online databases and tools.
Student activities
| 1 | DNA extraction from commercially important fish, using a simple Chelex resin extraction |
| 2 | PCR using primers targeting the 5S ribosomal gene spacer region |
| 3 | Agarose gel electrophoresis to examine PCR amplicons |
Prefer a printable version? Download the PDF guide.
4. DNA Fingerprinting Food Plants using RFLP
What type of plant is this?
In this practical, students identify a “mystery” plant by creating restriction fragment length polymorphism (RFLP) DNA fingerprints and comparing them to a panel of reference plants like tomato, basil, and parsley.
Proposed schedule
- Lab Sessions: Two blocks (2.5 hours each)
Why we like this practical
This lab is a great way to illustrate how genetic information can be more accurate for species identification than physical traits like leaf shape or color. The RFLP DNA fingerprint results are simple yet informative. Students match up identical patterns from different varieties of the same species, even when the plants look very different, such as flat leaf or curly leaf parsley or different varieties of basil.
It is also designed to be as foolproof as possible: students use fresh plant leaf tissue, a direct PCR plant kit, and a simple PCR setup. Demonstrator results are also provided in case of student error or sample failure. The article also contains student and teacher handouts in the supplementary data that may be useful in planning course materials for similar practicals.
Student activities
| 1 | DNA extraction from a mystery plant and a panel of identified plants |
| 2 | PCR of chloroplast gene regions using 3 universal plant primers |
| 3 | Digestion of PCR products using restriction enzymes |
| 4 | Agarose gel electrophoresis and interpretation of DNA fingerprint patterns |
PCR no longer needs to be a “theoretical-only” concept in classrooms. With compact tools like Bento Lab, hands-on molecular biology is possible — even in spaces without traditional lab infrastructure.
These activities give students a practical, memorable experience of how DNA is used in the real world, from biodiversity to human genetics.
For more educator tips, explore our Educator Resource Hub or see how Bento Lab is used in university courses.
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