An undergraduate laboratory module that uses the CRISPR/Cas9 system to generate frameshift mutations in yeast.

The CRISPR/Cas9 system is a powerful tool for gene editing and it has become increasingly important for biology students to understand this emerging technique. Most CRISPR laboratory teaching modules use complex metazoan systems or mammalian cell culture which can be expensive. Here, we present a lab module that engages students in learning the fundamentals of CRISPR/Cas9 methodology using the simple and inexpensive model system, Saccharomyces cerevisiae. Students use CRISPR/Cas9 and nonhomologous end joining to generate frameshift insertion and deletion mutations in the CAN1 gene, which are easily selected for using media plates that have canavanine. DNA sequencing is also performed to determine what type of mutation occurred in gene-edited cells. This easy to implement set of experiments has been run as both a 5-week and a shorter 3-week lab module. Learning assessments demonstrate increased understanding in CRISPR-related concepts as well as increased confidence using molecular techniques. Thus, this CRISPR/Cas9 lab module can be added to an existing Genetics, Microbiology, or Molecular Biology lab course to help undergraduate students learn current gene editing techniques with limited effort and cost.