Getting inside of the molecular pathways associated with intersex in the rainbow darter (Etheostoma caeruleum)

Rainbow darter (Etheostoma caeruleum) are a small benthic fish found in North America. This species is sensitive to sewage effluent in the environment, showing the presence of intersex in up to 80% of males in near-field areas in the Grand River, ON. To learn more about the molecular events associated with intersex, we developed a customized oligonucleotide microarray (4x180K) with next generation sequencing (454 Roche) to characterize molecular responses in the gonad. Transcriptomics was performed on both males and females from both a reference site and a polluted site. Males with and without intersex from the polluted site were compared to the control males. Rainbow darter were sampled from from the Grand River in May 2011. Fish were selected according to the location, gonad maturity, and intersex index. Reference fish were taken from the upstream to the urban area; exposed fish were taken from downstream of from Kitchener MWWE treatment plant.