Department of Ecology and Evolutionary, Biology University of California Irvine, Irvine, CA 92717, 714-856-5573, FAX: 714-725-2181, e-mail: RCBERKEL@uci.edu
Michael Dini
Department of Biology, Texas Tech University, Box 43131, Lubbock, TX 79409-3131, 806-742-2729, FAX: 806-742-2963
Lucile McCook
Department of Biology, University of Mississippi, Oxford, MS 38677, 601-232-5488, FAX: 601-232-5144
ACKNOWLEDGEMENTS: The laboratory exercise was developed by Berkelhamer, Dini and McCook during the NSF sponsored LABSHOP workshop, 13-18 June 1993.
ABSTRACT: This exercise introduces students to the basic concepts of Mendelian inheritance. It's strength is that this introduction is done in the context of an organism's entire life cycle, not as a disembodied, abstract assemblage of laws and principles. The exercise can be performed with any one of a number of varieties of Wisconsin Fast Plants (Brassica rapa), including the following traits, each inherited as a recessive: anthocyaninless, petalless, dwarf (shortened internode), giant (elongated internode), and yellow-green leaves. The experiment is as much about letting students practice scientific thinking as it is about Mendelian Genetics since students are asked to observe, formulate hypotheses, make predictions, design and execute experiments, and collect/analyze data. With very little assertion-making on the instructor's part, students will arrive at an understanding of monohybrid crosses in much the same way that Mendel did: by planning and performing crosses, harvesting seed, and analyzing the phenotypes of the germinated seeds. The experiment takes most of two 2-hour lab periods, these separated by about four weeks, and requires student maintenance of the plants in the interim.
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