Research for All: Large Introductory Laboratory Classes Investigate the Evolutionary Conservation of Metabolic Pathways

Abstract

The explosion of genomic sequence information, particularly for microbial organisms, presents opportunities to engage large numbers of undergraduate students in authentic research within regular laboratory classes. The Pathways over Time project was designed as a semester‐long research investigation in which students investigate the phylogenetic conservation of enzymes involved in a metabolic pathway. The project was designed to teach students core concepts of molecular biology, including evolution, structure/function relationships, information transfer, energy transformation and systems biology. Other course goals include the application of the scientific process, quantitative analysis, and the use of databases and bioinformatics tools.Each semester, 150–200 students enroll in 12 parallel sections of BIOL2040, Investigations in Molecular Cell Biology. Working in teams of three, students study the conservation of enzymes involved in methionine biosynthesis between the budding yeast, S. cerevisiae, and the fission yeast, Schizosaccharomyces pombe, species separated by close to a billion years of evolution. Methionine biosynthesis in yeast involves several multi‐enzyme pathways, which are subject to a variety of regulatory controls. Working in teams of three, students become “experts” on one particular MET gene as they learn the basic techniques of microbiology, bioinformatics, molecular cell biology and genetics. The rapid pace of the course does not allow students to repeat experiments. Instead, students post their data to a data‐sharing wiki site to determine if their results are reproducible.Student learning is assessed with pre‐lab quizzes, lab notebooks, oral and poster presentations, database and literature assignments, and a series of “micro‐reports” that are assembled into a final research report in the format of a scientific publication. Pre‐and post‐course evaluation instruments include concept tests and self‐assessed confidence and learning gains. Assessment data indicate significant gains on all measures.The Pathways over Time project was designed with sustainability in mind. The project can be easily adapted to other organisms and enzyme systems, depending on instructor experience and interest. The three elements required for course design are a multi‐gene system to study, a genetically‐tractable organism for complementation analyses, and a test organism with a sequenced genome. At Boston College, for example, students have successfully demonstrated the conservation of multiple MET gene functions between S. cerevisiae and S. pombe. Moving forward, Boston College will use a new test organism in which MET gene function has been predicted from DNA sequence comparisons, but function has not been tested by complementation.Support or Funding InformationNational Science Foundation grant 114028