Cell migration is a basic developmental function that serves to build tissues, organs, and whole animals. Defects in cell migration are associated with birth defects and cancer, in particular the metastasis of tumors. Over the past forty years researchers have used the fruit fly to understand the genetic basis of development, including cell migration, but many of the tools and approaches used are beyond the skills and understanding of an undergraduate and advanced high school lab. We have developed a practical lab that allows students to use fly oogenesis to understand how genes regulate cell migration. Students learn to sort males from females, recognize fly genetic markers to identify wild type and mutant animals, hand-dissect ovaries, perform histochemical staining to reveal gene expression in this tissue, and visualize normal and aberrant cell migration using light microscopy to distinguish the effect of a key mutation in a gene required for cell migration. From this approach, students learn how mutations can aid in understanding gene function and how modern genetic tools and microscopy are used to study gene expression and development. Because these genes have human homologs, students learn how model organisms can be used to understand the molecular basis of disease and disorders, such as cancer.