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

Course-embedded undergraduate research experiences (CUREs) for students have been shown to increase students’ 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. Citation: Makarevitch I, Goering R. 2022. Learning quantitative genetics: Investigation of genetic control for cold stress response in plants. CourseSource. https://doi.org/10.24918/cs.2022. 4 Editor: Megan Barker, Simon Fraser University Received: 2/23/2021; Accepted: 8/31/2021; Published: 2/14/2022 Copyright: © 2022 Makarevitch and Goering. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original author and source are credited. Conflict of Interest and Funding Statement: None of the authors has a financial, personal, or professional conflict of interest related to this work. This work was supported by NSF awards (IOS 1444456). Supporting Materials: Supporting Files S1. QTLs of Maize Cold Response – Detailed Timeline; S2. QTLs of Maize Cold Response – Student Handout; S3. QTLs of Maize Cold Response – Sample Answers to the Questions of the Worksheets; S4. QTLs of Maize Cold Response – Multiple Choice Assessment Quiz with Correct Answers; S5. QTLs of Maize Cold Response – Rubric Used for the Assessment of Student Skills in Data Analysis and Interpretation in the Lab Reports; S6. QTLs of Maize Cold Response – Genetic Architecture of the Lines Used in This Study; S7. QTLs of Maize Cold Response – Sample Phenotypic Data Collected by Students; and S8. QTLs of Maize Cold Response – Sample Formatted Data File Ready with Visual Scoring Data for QTL Analysis. *Correspondence to: 1536 Hewitt Ave, Saint Paul, MN 55104; imakarevitch01@hamline.edu CourseSource | www.coursesource. org 2022 | Volume 09 1 Lesson