Using Student-Generated UV-Induced Escherichia coli Mutants in a Directed Inquiry Undergraduate Genetics Laboratory

Abstract

We report a thematic sequence of directed inquiry-based labs taking students from bacterial mutagenesis and phenotypic identification of their own self-created mutant, through identification of mutated genes by biochemical testing, to verification of mutant alleles by complementation, and finally to mutant allele characterization by DNA sequence analysis. The lab utilizes UV mutagenesis with wild-type Escherichia coli and a UV-sensitive isogenic derivative optimized for undergraduate use. The labs take advantage of the simplicity of E. coli in a realistic genetic investigation using safe UV irradiation methods for creation and characterization of novel mutants. Assessment data collected over three offerings of the course suggest that the labs, which combine original investigation in a scientifically realistic intellectual environment with learned techniques and concepts, were instrumental in improving students' learning in a number of areas. These include the development of critical thinking skills and understanding of concepts and methods. Student responses also suggest the labs were helpful in improving students' understanding of the scientific process as a rational series of experimental investigations and awareness of the interdisciplinary nature of scientific inquiry.A S scientist educators we strive to involve students in the process of active, engaged scientific inquiry, where they can benefit in a number of ways from involvement in projects where they are ''doing real science'' as opposed to performing scripted ''cookbook'' activities. These include (1) gaining an understanding of how scientific studies are conducted, (2) confirming that such studies yield credible results, and (3) seeing how engaging scientific discovery can be. The report of the Committee on Undergraduate Biology Education to Prepare Scientists for the 21st Century underscored the significance of involving and inspiring students through active learning to better prepare them as future scientists and ''give them an enduring sense of the power and beauty of creative inquiry'' (National Research Council 2003, p. 2). Findings also emphasized the importance of interdisciplinary research experiences and using ''examples of research showing that science consists of unanswered questions''to ''intrigue and inspire students to probe problems in depth' ' (National Research Council 2003, p. 3).The integration of discovery-based exercises into undergraduate genetics laboratory curricula poses many challenges. These include budget limitations, performing activities within prescribed laboratory period constraints, and student mastery of techniques as a prerequisite to actual experimentation. However, the rewards of active and discovery-based approaches are substantial (Handelsman et al. 2004). As compared to traditional approaches, active-learning exercises can result in increased knowledge retention, student confidence, enthusiasm, and satisfaction (Wyckoff 2001;Smith et al. 2005). Marcus and Hughes developed inquiry-based genetics lab exe...

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