Genetic variation is historically challenging for undergraduate students to master, potentially due to its grounding in both evolution and genetics. Traditionally, student expertise in genetic variation has been evaluated using Key Concepts. However, Cognitive Construals may add to a more nuanced picture of students' developing expertise. Here, we analyze the occurrence of Key Concepts and Cognitive Construals among three types of student representations: interviews, drawn models, and constructed responses (CRs). Our mixed-methods analysis indicates that differential survival and differential reproduction occur more often in interviews than in CRs. In our interviews, presence of Cognitive Construals indicate varying levels of understanding of genetic variation, but we were not able to detect Cognitive Construals in students' models or CRs. Finally, our analyses of both Key Concepts and Cognitive Construals in student representations indicate that Cognitive Construals can co-occur with any number of Key Concepts, and that the presence of Construal-based language alone does not seem to correlate to the expert nature of a response. Taken together, our results highlight the need for instructors to avoid treating Construal-based language as implicit disconnects in student understanding, and to use multiple methods to gain a holistic picture of student expertise.