Acknowledgements
The study was supported by the Norwegian Research Council (Grant Number 196639). Sequencing was provided by the Norwegian Sequencing Centre (www.sequencing.uio.no), a national technology platform hosted by the University of Oslo and supported by the “Functional Genomics” and “Infrastructure” programs of the Research Council of Norway and the Southeastern Regional Health Authorities. We thank Tina Arntsen, Anders Herland and Haaken Hveding Christensen for assistance with fish maintenance, Tina Arntsen, Martin Malmstrøm, Nanna Winger Steen, Ave Tooming-Klunderud and Mari Espelund for help in the lab, Robert Lyle for assisting in transcriptome alignments, Alexander J. Nederbragt and Bastiaan Star for interesting discussions and ideas and Rose Keller for proofreading, and correcting, all our mistakes in English grammar.