When poisons overtake your home: how the Atlantic killfish adapted to the toxicants in its environment


The Atlantic killifish inhabits both pristine and polluted environments. Interestingly, populations that inhabit areas contaminated with polychlorinated biphenyls (PCBs) have developed a resistance to these toxicants that the populations of pristine environments do not have. My aim for this summer was to explain this difference at the protein level. One protein, the aryl hydrocarbon receptor, was central to my investigation. It mediates the toxic response by binding to toxicants like PCBs and then affecting the cell’s health by altering gene regulation as a transcription factor. Further, this protein exists in structurally unique variants between the resistant and non-resistant populations. To determine if this structural difference corresponded to a functional difference, I used a luciferase reporter assay to compare the levels of transcriptional activity between cells expressing each of the variants. Ultimately, the variants of the resistant population exhibited less activity in response to a given concentration of toxicant than the variants of the non-resistant population.