Evolved Pollution Tolerance in Gulf Killifish (Fundulus grandis) from the Corpus Christi Inner Harbor, Texas




Walkup, Rachel

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The Corpus Christi Inner Harbor in Texas is a major center of industrial activity and has significant levels of persistent pollutants including dioxins, furans, polycyclic aromatic hydrocarbons (PAHs), and polychlorinated biphenyls (PCBs). The Gulf killifish, Fundulus grandis, is an estuarine species of fish that is known to inhabit the Gulf of Mexico and F. grandis populations from Houston, Texas have demonstrated resistance to PCB-induced cardiac teratogenesis via a recalcitrant AHR pathway. In this study, F. grandis embryos spawned from individuals collected from two sites in the Corpus Christi Inner Harbor were exposed to varying doses of PCB-126 and then screened for heart deformities at 144 hours post fertilization. Both populations displayed significant resistance to PCB-induced cardiac teratogenesis when compared to a reference population. This represents the second documented cluster of adapted populations of F. grandis. Additionally, Corpus Christi populations displayed lower basal and induced cytochrome P450A (CYP1A) activity indicating that a recalcitrant AHR pathway is likely at least a partially responsible for PCB resistance. Finally, it was also found in this study that while PCB-induced cardiac teratogenesis and CYP1A induction were highly correlated on a population level, these two factors did not appear to be correlated at the individual level, as individual CYP1A activity was not predictive of heart deformity.



Toxicology., Environmental toxicology., Evolutionary toxicology.