Providing learners with opportunities to engage in activities similar to those carried out by scientists was addressed in a web-based research simulation in genetics developed for high school biology students. The research simulation enables learners to apply their genetics knowledge while giving them an opportunity to participate in an authentic genetics study using bioinformatics tools. The main purpose of the study outlined here is to examine how learning using this research simulation influences students' understanding of genetics, and how students' approaches to learning using the simulation influence their learning outcomes. Using both quantitative and qualitative procedures, we were able to show that while learning using the simulation students expanded their understanding of the relationships between molecular mechanisms and phenotype, and refined their understanding of certain genetic concepts. Two types of learners, research-oriented and task-oriented, were identified on the basis of the differences in the ways they seized opportunities to recognize the research practices, which in turn influenced their learning outcomes. The research-oriented learners expanded their genetics knowledge more than the task-oriented learners. The learning approach taken by the research-oriented learners enabled them to recognize the epistemology that underlies authentic genetic research, while the task-oriented learners referred to the research simulation as a set of simple procedural tasks. Thus, task-oriented learners should be encouraged by their teachers to cope with the scientists' steps, while learning genetics through the simulation in a class setting.