From Gene to Function: A Safe Laboratory Exercise Promoting the Learning of the Central Dogma of Biology for the Undergraduate Biology Curriculum.

Abstract

The central dogma of biology, which explains how the information in genes flows into proteins, can be challenging to teach in the undergraduate classroom. To allow students to understand the correlation between genes and protein functions, we have developed a practical laboratory activity that complements classroom learning. By using PCR analysis targeting the flagellin gene flgA1, students will investigate the genotype of an unknown strain of Haloferax volcanii, a halophilic archaeon appropriate for activities with undergraduates as it is nonpathogenic, inexpensive, easy to grow using “grocery store ingredients,” and offers many genetic tools. This species swims by means of flagella, and its motility can be tested using modified agar plates. Motile colonies will form swimming halos; meanwhile motility mutants will show only a dot on the motility plate, at the point of inoculation. First students will extract DNA for PCR amplification. They will not be told whether the strain they are assigned is motile or not. They will learn how to design primers for the target gene and set up the PCR reaction. Subsequently they will set up a motility assay and control of the provided strain. In the next laboratory period, students perform gel electrophoresis on the products of their PCR reactions and analyze the results. They compare these to the results of the motility assay to confirm the motility of the strain. In summary, this inquiry-based lab is easy and safe to perform and allows students to follow the information flow from a gene to a protein product.