Development of higher-level cognitive skills in a learner-centered lab on extensions of mendelian inheritance using Drosophila.

Students can have difficulty comprehending complex concepts in science. They can memorize the definition but do not understand the underlying biological principles. In the Fundamentals of Genetics course at Arizona State University at the West campus, students grapple with the topic of "extensions of Mendelism." Additionally, in lab, students are challenged by scoring phenotypes that are not binary. Both of these concepts require that students understand not only inheritance but also the principles of protein structure and function. A genetics laboratory exercise was developed that combines study of some extensions of Mendelian inheritance with practice in manipulating Drosophila melanogaster and scoring subtle and variable phenotypes. Students analyze Drosophila with mutations that demonstrate some extensions of Mendelian inheritance: temperature sensitivity, variable expressivity, incomplete penetrance, multiple alleles, dosage compensation, and gene dosage effect. The phenotypes in some of these mutants differ from individual to individual and are difficult to discern; thus, students also gain experience in investigating challenging phenotypes. Pre- and postlab assessments indicate that performing this exercise increased students' mastery of the molecular basis of extensions of Mendelian inheritance and their abilities in scoring and manipulating flies. This is a discovery-based lab exercise in which students examine some extensions of Mendelian inheritance and gain experience in analyzing complex traits in Drosophila.