Document Type

Paper- Restricted to Campus Access

Publication Date


Faculty Mentor

Kate Goddard


Populations of the killifish Fundulus heteroclitus surrounding Superfund Sites have been found to have evolved resistance to PAHs and DLCs toxicity and teratogenesis. The resistance mechanism has been thought to derive from the Aryl Hydrocarbon Receptor (AHR) pathway encoding a ligand activated transcription factor that drives expression of xenobiotic enzymes such as Cytochrome P450. To study possible resistance in a local Upper Delaware Bay population, we analyzed single nucleotide polymorphisms (SNPs) in Exon 10 of AHR1a in Fundulus heteroclitus downstream of a United States Environmental Protection Agency (USEPA) designated superfund site in the Lower Darby Creek in the John Heinz National Wildlife Refuge near Philadelphia, Pennsylvania. Individuals from this freshwater site were compared to individuals from a nearby freshwater control site, the Muckinipattis Creek and a marine control site, Ocean City, NJ. In this study we report that the northern subspecies Fundulus heteroclitus macrolepidotus is fixed in Lower Darby Creek and Muckinipattis Creek populations and that the southern subspecies Fundulus heteroclitus heteroclitus is fixed in the Ocean City, New Jersey population. The former two populations are the furthest north populations of Delaware Bay populations whose subspecies status has been studied. We found no definitive evidence of hybridization between F. heteroclitus macrolepidotus and F. diaphanus in the freshwater populations although clonal hybrids between these two species are reported elsewhere. SNPs discovered in exon 10 of AHR1a were significantly divergent from control populations, which may play a role in pollution resistance in Fundulus heteroclitus in the Lower Darby Creek.


Presented as part of the Ursinus College Celebration of Student Achievement (CoSA) held April 22, 2021.

The file available for download is a poster with research findings.

This research was also presented at the Society for Integrative and Comparative Biology (SICB) annual 2021 meeting.


Available to Ursinus community only.