Data from: "De novo assembled transcriptome of organs involved in reproduction in an endangered endemic Iberian cyprinid fish (Squalius pyrenaicus)" in Genomic Resources Notes Accepted 1 June 2015 to 31 July 2015

Sex determination systems are diverse, especially among fish, and include genetic and/or environmental components. Unexpectedly for such a basic aspect of development, sex determination systems change rapidly during evolution and gonadal fate is not ultimate, being actively maintained lifelong. Here, sequences of expressed genes involved in maintenance of gonad identity and reproduction processes were obtained through transcriptome assembly of the brain-gonadal axis tissues of a freshwater fish inhabiting highly variable environments, the gonochoristic Iberian fish Squalius pyrenaicus. Through Illumina total RNA-sequencing, male and female transcriptomes of brain and gonad tissues were assembled with Trans-ABySS software and merged to produce a more comprehensive S. pyrenaicus transcriptome. Coding sequences (CDS) predicted by TransDecoder were annotated using blastx. By means of read mapping against the reference transcriptome and CDS datasets, using Bowtie2, the accuracy of read mapping was assessed. This first endemic Iberian cyprinid transcriptome of organs involved in reproduction processes may serve as a valuable genomic resource for studying sexual mechanisms and other aspects of evolution, such as speciation and responses to environmental changes, and may be a useful tool for conservation studies since S. pyrenaicus is an endangered species