An Inquiry-Infused Introductory Biology Laboratory That Integrates Mendel’s Pea Phenotypes with Molecular Mechanisms

We developed a multi-week laboratory in which college-level introductory biology students investigate Mendel’s stem length phenotype in peas. Students collect, analyze and interpret convergent evidence from molecular and physiological techniques. In weeks 1 and 2, students treat control and experimental plants with Gibberellic Acid (GA) to determine whether uncharacterized short mutant lines are GA responsive. These data allow students to place the mutation in the GA signal transduction pathway. During weeks 2 and 3, plants are genotyped for Mendel’s le mutation using a derived cleaved polymorphic sequences (dCAPS) PCR assay. This laboratory allows students to make a direct connection between modern molecular genetics and the easily scored phenotypes Mendel used as the basis of his fundamental discoveries. We administered surveys to assess student gains in accord with four learning goals: understanding the lab, basic science literacy, scientific practices, and working collaboratively. Student confidence increased significantly in the first three, but not in working collaboratively, although students reported greater confidence working in groups than alone.