To overall aim of the project is to examine whether exposure of roach populations to estrogenic wastewater (WwTW) effluents over multiple generations has resulted in genetic selection and the impacts of selection on the susceptibility in male fish to develop oestrogen-induced effects associated with negative fitness consequences. Specifically these genomic sequences were generated to identify genomic regions associated with single nucleotide polymorphisms -SNPs identified from transcriptome sequencing from wild fish. These data will then be used to test whether candidate genes have signatures of selection in roach populations confined to rivers with a high proportion of estrogenic effluent.