3W

A semester-long laboratory project synthesizing molecular and classical approaches to gene mapping and cloning. K. Hales. Department of Biology, PO Box 1719, Davidson College, Davidson, NC 28036, (704) 894-2324.

In laboratory courses, students enjoy pursuing previously unanswered questions, as opposed to cookie-cutter style experiments with preordained outcomes. While the uncertain result of such an approach can be a drawback for the instructor, it is precisely this sense of breaking new ground that leaves a lasting impression on the students. I will describe a semester-long genetics laboratory project that begins with a recessive lethal w+-marked P-element insertion line, which I generated in a previous P-element mobilization experiment. I knew only that the insertion was on the third chromosome. During the semester, students perform plasmid rescue, determine the sequence of DNA flanking the insertion site, and analyze the sequence in order to understand the biological basis for the observed phenotype. In parallel, they carry out a series of crosses to assess linkage between the P element insertion and known visible markers on the third chromosome. Both sets of experiments are designed with enough redundancy among lab groups so that reagents and data can be shared if there is a mistake at any step. At the end of the semester, students correlate the results of both experiments, analyzing data pooled from the entire class.