As a Howard Hughes Medical Institute (HHMI) undergraduate researcher in the Tanguay Laboratory, Annika Swanson is studying the effects of developmental exposure to oxygenated polycyclic aromatic hydrocarbons (OPAHs). Polycyclic aromatic carbons (PAHs) are a family of chemicals with multiple fused carbon rings, some of which cause developmental abnormalities and cancer. They are formed through the combustion of fossil fuels and are of increasing concern as they have become widespread environmental contaminants. Oxygenated forms of PAHs are created through multiple processes and are widely present in the environment, although little is known about the impacts of exposure to these contaminants. Recent studies suggest that PAHs and OPAHs have different toxic potentials due to subtle differences in chemical structure. The Tanguay Laboratory utilizes zebrafish as a model organism to investigate the causes of PAH toxicity during development. Swanson's research focuses on determining whether the toxicity caused by different OPAH structures occurs through the activation of a family of receptors, the aryl hydrocarbon receptors (AHRs). She uses the CYP1A protein as a biomarker of receptor activation and uses immunohistochemistry to examine temporal and spatial CYP1A expression in zebrafish larvae exposed to OPAHs during development.