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Pollutants, as a result of wastewater treatments, have been shown to have negative impacts on aquatic ecosystems. To better understand the possible consequences caused by effluents on ecosystems, it is important to examine ecotoxicology data. One of the most commonly used species for water quality testing is the fathead minnow, Pimephales promelas. Ecotoxicology can then be taken one step further to understand the effects of pollutants on a molecular level. Previous research had identified effluents as causes for abnormal minnow fin morphology. In order to collect additional data on development, tanks with fathead minnows were placed at the Charleston Wastewater Treatment plant effluent, the Decatur Wastewater Treatment Plant effluent, and control tanks at EIU's H.F. Thut Greenhouse. Fathead minnows were randomly sampled for about eight weeks and underwent immunofluorescence staining and imaging for sonic hedgehog (shh) gene expression. The data collected indicates that sonic hedgehog gene may not be responsible for fin bud development or is expressed at a different time. Expression of shh was only seen in three samples: two anal fin expressions in 23 dph (days post hatching) and one dorsal fin expression in 38 dph. I concluded that late expression of shh is not responsible for the differences seen in fin growth ratios. There are different possible explanations for not seeing late shh expression: it is expressed mainly during a different developmental period, pollutant impact during critical growth period, or upregulation of another pathway replacing shh expression. Follow up studies should explore the fathead minnow's critical period of shh expression and specific pollutants that might disrupt the shh pathways.
Greiner, Brooke Renee, "Exploration of Sonic Hedgehog Gene Expression in Fathead Minnows (Pimephales promelas)" (2019). Undergraduate Honors Theses. 150.