Application of a bacterial experimental evolution system to visualize and teach evolution in action: A course-based undergraduate research experience.

Abstract

Concepts of evolution are typically taught through examples of extremely long timescales, which do not always resonate broadly. Here, we describe a course-based undergraduate research experience tailored for junior and senior undergraduate biology majors. Students visualize and learn in real-time how evolution can operate in bacteria in response to problems associated with a high-density lifestyle. Students directly evolve mutant strains, conduct whole genome sequencing to identify the causal mutations, carry out bioinformatics analysis to predict molecular consequences of the mutations, engineer their mutants to become antibiotic-resistant, and compete them head-to-head in a class-wide round-robin tournament to infer the properties of natural selection. The presented format is designed for a full semester, but the modular structure of the course allows instructors to make simple modifications for a shorter duration. A substantial portion of this course also focuses on scientific communication. Each student prepares a lab report structured as an original research article to gain experience in writing a publication quality manuscript. Individual components of their reports are prepared throughout the semester and are followed with instructor- and peer-based draft edits. Finally, students are tasked with working as a team to deliver an oral presentation, which drives them to come to a consensus on the interpretation of their group's data. Such a comprehensive research experience is difficult for a student to acquire without securing a research position in a faculty lab, but this course allows a large group of students to directly experience and actively contribute to open-ended and hypothesis-driven research.