Learning Quantitative Genetics: Investigation of Genetic Control for Cold Stress Response in Plants

Abstract

Course-embedded undergraduate research experiences (CUREs) for students have been shown to increase students&rsquo; understanding of the process of science, affirm their scientific identity, and improve retention in STEM fields. Despite many CUREs recently developed for introductory biology, genetics, biochemistry, and molecular biology courses, projects related to quantitative genetics and polygenic inheritance are rare. Students frequently struggle with the uncertainty and complexity of quantitative genetic studies in a traditional genetics course. This lesson describes a series of laboratory exercises that provide an authentic research experience focused on quantitative trait loci (QTL) analysis of the traits related to cold stress response in plants. Maize varieties show a large variation in the degree of their response to stress, suggesting that this trait is highly heritable, even though most of the genes contributing to this trait remain elusive. The results of the QTL analysis vary depending on the plant material used in the study and the specific traits measured in the study, reflecting the polygenic nature of the trait. This laboratory project allows students to make decisions about the details of the experimental design, collaborate with their peers, conduct the experiments, and analyze the results using standard protocols for the QTL analysis. The accompanying worksheets and supplemental instruction demonstrate the complex architecture of quantitative traits and their dependency on the number of plants involved in the analysis and the details of the experimental design. The laboratory series invites students to discuss the nature of the scientific investigation. <em>Primary image:&nbsp;</em>Different Maize Varieties Show Variation in Cold Stress Tolerance.&nbsp;When exposed to 8 hours of 60⁰C, B73 maize seedlings exhibit severe stress response, including dying leave edges and tips and leaf curling.&nbsp; Mo17 maize seedlings are resistant to cold stress under these conditions and show no stress response phenotype.&nbsp; The image was taken by the authors.