In the learning sciences, students' understanding of scientific concepts has often been approached in terms of "conceptual change". These studies are grounded in a cognitive or a socio-cognitive approach to students' understanding and imply a focus on the individuals' mental representations of scientific concepts and ideas. We approach students' conceptual change from a socio-cultural perspective as they make new meaning in genetics. Adhering to a socio-cultural perspective, we emphasize the discursive and interactional aspects of human learning and understanding. This perspective implies that the focus is on students' meaning making processes in collaborative learning activities. In the study, we conduct an analysis of a group of students' who interact while working to solve problems in genetics. In our analyses we emphasize four analytical aspects of the students' meaning making: (a) the students' use of resources in problematizing, (b) teacher interventions, (c) changes in interactional accomplishments, and (d) the institutional aspect of meaning making. Our findings suggest that students' meaning making surrounding genetics concepts relates not only to an epistemic concern but also to an interactional and an institutional concern.