This study explores how pre-service biology teachers construe the concept of “ancestry,” situated at the crossroads of genetics, evolution, and cultural identity. We used the repertory grid method, which is based on the theory of the psychology of personal constructs, according to which there are different ways to construe the world as each individual identifies different patterns. We thus provided participants with the opportunity to express their construal of “ancestry”. An important feature of this method is that participants are asked to assign a meaning to a concept by way of contrast with another concept. Six secondary-level pre-service teachers compared ten ancestryrelated elements (e.g., “mitochondrial Eve,” “grandparent,” “LUCA” etc.) through triadic elicitation, generating personal constructs. Principal component analysis (PCA) of the pooled data revealed two main dimensions: one contrasting scientific and genetic framings with genealogical and cultural ones, and another distinguishing ancestries perceived as African and human from those viewed as non-African, non-human, or ancient. These findings suggest that participants' understanding of ancestry is organized along both epistemological and evolutionary axes. Despite the small sample size, the study highlights the potential of the repertory grid method to capture tacit conceptual structures in science education. A larger analysis is underway to confirm these initial results and support teacher education on complex and interdisciplinary topics such as ancestry.