Using Geneswitch technolgy to teach sex differentiation for undergraduates

The development and evaluation of a two-session laboratory class, based on Geneswitch technology and sex determination in the fruit fly Drosophila melanogaster, is described. Geneswitch system allows conditional control of gene expression. A laboratory exercise has been devised for sophomores in order to illustrate how Geneswitch technology can be used to conditionally over-express the key sex determination gene transformer (tra) during development, and how this inhibits sexual differentiation in males, resulting in a lack of much of the external genitalia and a reduction in the size of the sex combs. The protocol is inexpensive and straightforward, at the meantime gives students a good understanding of how molecular biology technologies can change biological processes including development.