Mutagenesis screens and analysis of mutant phenotypes are one of the most powerful approaches for the study of genetics. Yet genetics students often have difficulty understanding the experimental procedures and breeding crosses required in mutagenesis screens and linking mutant phenotypes to molecular defects. Performing these experiments themselves often aids students in understanding the methodology. However, there are limitations to performing genetics experiments in a student laboratory. For example, the generation time of laboratory model organisms is considerable, and a laboratory exercise that involves many rounds of breeding or analysis of many mutants is not often feasible. Additionally, the cost of running a laboratory practical, along with safety considerations for particular reagents or protocols, often dictates the experiments that students can perform. To provide an alternative to a traditional laboratory module, we have used Scenario-Based-Learning Interactive (SBLi) software to develop a virtual laboratory to support a second year undergraduate course entitled "Genetic Analysis." This resource allows students to proceed through the steps of a genetics experiment, without the time, cost, or safety constraints of a traditional laboratory exercise.