Johanna Kowalko serves as an Associate Professor in the Department of Biological Sciences at Lehigh University, where she maintains an active research program focused on evolutionary and behavioral genetics. Her laboratory investigates the genetic and neural mechanisms underlying behavioral diversity using Astyanax mexicanus (blind cavefish) as a model system. The cavefish model provides unique opportunities to study convergent evolution through independently colonized cave populations. Her primary research interests center on four interconnected themes: (1) How natural genetic variation alters developmental processes to produce phenotypic change, particularly eye regression in cavefish; (2) The role of pleiotropy in behavioral evolution, especially the relationship between albinism and sleep loss; (3) The evolution of behavioral plasticity in response to environmental conditions like nutrient availability; and (4) Evolutionary approaches to identify genetic architecture regulating social behavior, comparing highly social surface fish with cave-adapted populations showing reduced social behaviors. Her work bridges developmental biology, neuroscience, and evolutionary genetics to understand how behaviors evolve. Dr. Kowalko's recent publications demonstrate significant contributions to understanding convergent evolution of cave adaptations, with particular emphasis on sleep regulation, circadian rhythms, and sensory system modifications. Her research has revealed how the oca2 gene pleiotropically influences both albinism and sleep loss in cavefish populations. Her scientific recognition includes being featured as an In the Spotlight – Early Career Researcher in the Journal of Experimental Zoology B. She has contributed to major collaborative efforts including the chromosome-level genome assembly of Astyanax mexicanus . Dr. Kowalko actively develops genetic and experimental methodologies for cavefish research, including CRISPR-based genome editing techniques. Her laboratory examines both laboratory and wild populations to understand the environmental contexts driving evolutionary changes in behavior and morphology. Current field research focuses on defining sleep, feeding, and social behaviors in natural cave environments to identify selective pressures shaping these adaptations.










