Teaching With C. elegans

C. elegans has grown its popularity in the classroom. At the 12th C. elegans Meeting held at the University of Wisconsin-Madison in 1999, several educators presented their uses of C. elegans as an educational model. The reasons they use C. elegans in teaching are similar to why biologists use C. elegans as a model system in research.

This small worm is paving its way in educational use due to its short life cycle, its small size, its transparent body, its ease of cultivation, its ability to be crossed at will and the similarity of its genome to that of the human. In addition to these advantages, the available resources, such as the stock of mutants, the completion of its genome sequence, and various advanced tools, make it easy to use C. elegans in classrooms.

Being able to house C. elegans and culture it in the classroom is the first step to use it in teaching. It is also a good model organism for students to watch animal behavior, because C. elegans shows a diversity of behaviors. It can taste, smell, and sense light and temperature. These characteristics make C. elegans a good experimental organism for students to study behavior (Aamodt, 1999; DeStasio, 1999).

Large numbers of mutant stocks make it an attractive teaching material as well. It is easy to get a mutated worm with a desired trait. For example, motional defective worms can be used to teach muscle physiology or for students to understand how mutations influence a worm's phenotype. Various mutagens can be used to produce mutants. For instance, ethylmathanesulforate (EMS) is a mutagen that induces direct mutations in DNA, such as missense and nonsense mutations. In teaching genetics, the selection of mutants is essential and EMS can be used to treat C. elegans to produce desired mutants (Miller, 1999; Morgan, 1999b; Sulcove & Allen, 1999).

The discovery of reporter genes can be used to show when and where a protein is expressed that implies the expression of a gene. The green fluorescent protein (GFP) reporter gene is a gene cloned from jellyfish. It can be fused to a piece of DNA and expressed with that gene. By observing the worm with the green fluorescent protein under a microscope, the expression of a gene can be seen, and its timing, location and quantity of the gene expression can be monitored (Aroian, Johnson, & Wienhausen, 1999; Miller, 1999; Morgan, 1999b). In addition, the invention of advanced microscopes and the completion of the complete C. elegans cell lineage are good for teaching development. Generally speaking, the motility of C. elegans can be observed by using dissecting microscopes. However, by using advanced microscopes, such as Nomarski optics, students can observe the process of development and morphogenesis in a single cell (Miller, 1999).

Available molecular techniques are useful to help students learn more advanced topics. For instance, the Polymerase Chain Reaction (PCR) can be used to detect the existence of a specific gene in C. elegans. Chemical reagents, such as colchicine, an alkaloid toxic, which interrupts cell division at mitosis, can be used to study cell division and development (Lissemore, Lackner, & Fedoriw, 1999; Miller, 1999).

As more resources become available for a model experimental system, its success as an educational model increases. As Robert Waterston said, the completion of C. elegans genome is a start rather than an end in the biological research, thus, it is predictable that there will be more discoveries based on the use of C. elegans that will make it a more attractive model organism in the curriculum.

Credits

  • Cell Junction in GFP: Bill Mohler (Mohler lab), John White Lab (work done at the White lab).

References

  • Aamodt, S. (Personal communication, Jun 5, 1999). C. elegans: a model organism for teaching?
  • Aroian, R., Johnson, D., & Wienhausen, G. (Personal communication, Jun 5, 1999). Using C. elegans to teach embryonic development to undergraduates.
  • DeStasio, E. (Personal communication, Jun 5, 1999). C. elegans in introductory biology projects.
  • Lissemore, J. L., Lackner, L. L., & Fedoriw, G. D. (Personal communication, Jun 5, 1999). Using PCR in an undergraduate lab course to detect deletions in the unc-93 gene.
  • Miller, L. M. (Personal communication, Jun 5, 1999). A project-based laboratory course using C. elegans.
  • Morgan, W. R. (Personal communication, Jun 5, 1999b). Use of C. elegans in undergraduate biology courses.
  • Sulcove, J., & Allen, T. (Personal communication, Jun 5, 1999). Development of an open-ended muscle physiology experiment with C. elegans.
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