This study describes a lab in which students engaged in inquiry in classical genetics in order to develop a better understanding of the concepts and reasoning skills necessary to support knowledge claims about genetics. The simulation program called Drosofly can be used to foster about the conceptual knowledge used by university students when investigating the genetic's determinism of traits in drosophila. An analysis of the procedural knowledge for experimenting with the computer model is provided. The results of this case study provide a model of how Drosofly can be used to engage students in a complex problem-solving experience that encourages their meta-cognitive reflection and understanding about laws of the genetics. Implications for teaching are provided and ways to improve student learning and problem solving in classical genetics are suggested.