title: Beyond Punnett squares: Student word association and explanations of phenotypic variation through an integrative quantitative genetics unit investigating anthocyanin inheritance and expression in Brassica rapa Fast plants.
abstract: Genetics instruction in introductory biology is often confined to Mendelian genetics and avoids the complexities of variation in quantitative traits. Given the driving question "What determines variation in phenotype (Pv)? (Pv=Genotypic variation Gv + environmental variation Ev)," we developed a 4-wk unit for an inquiry-based laboratory course focused on the inheritance and expression of a quantitative trait in varying environments. We utilized Brassica rapa Fast Plants as a model organism to study variation in the phenotype anthocyanin pigment intensity. As an initial curriculum assessment, we used free word association to examine students' cognitive structures before and after the unit and explanations in students' final research posters with particular focus on variation (Pv = Gv + Ev). Comparison of pre- and postunit word frequency revealed a shift in words and a pattern of co-occurring concepts indicative of change in cognitive structure, with particular focus on "variation" as a proposed threshold concept and primary goal for students' explanations. Given review of 53 posters, we found ∼50% of students capable of intermediate to high-level explanations combining both Gv and Ev influence on expression of anthocyanin intensity (Pv). While far from "plug and play," this conceptually rich, inquiry-based unit holds promise for effective integration of quantitative and Mendelian genetics.
authors.affiliation: *Biology Core Curriculum, University of Wisconsin-Madison, Madison, WI 53706 jcbatzli@wisc.edu.
authors.forename: Janet M
authors.initials: JM
authors.lastname: Batzli
authors.affiliation: Center for Research on Teaching and Learning, University of Michigan, Ann Arbor, MI 48109.
authors.forename: Amber R
authors.initials: AR
authors.lastname: Smith
authors.affiliation: Wisconsin Fast Plants, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Paul H
authors.initials: PH
authors.lastname: Williams
authors.affiliation: *Biology Core Curriculum, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Seth A
authors.initials: SA
authors.lastname: McGee
authors.affiliation: *Biology Core Curriculum, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Katalin
authors.initials: K
authors.lastname: Dósa
authors.affiliation: *Biology Core Curriculum, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Jesse
authors.initials: J
authors.lastname: Pfammatter
mesh_terms: D000872:Anthocyanins / Q000235:genetics*; D001937:Brassica / Q000235:genetics*; D004521:Educational Measurement; D005260:Female; D005823:Genetics / Q000193:education*; D006801:Humans; D040582:Inheritance Patterns / Q000235:genetics*; D008297:Male; D010641:Phenotype; D057566:Self Report; D013334:Students; D014936:Word Association Tests
chemical_list: D000872:Anthocyanins