Sequential hermaphroditism is a unique reproductive strategy among teleosts that is displayed mainly in fish species living in the coral reef environment. The reproductive biology of hermaphrodites has long been intriguing; however, very little is known about the molecular pathways underlying their sex change. Here, we provide the first de novo transcriptome analyses of a hermaphrodite teleost´s undergoing sex change in its natural environment. Our study has examined relative gene expression across multiple groups—rather than just two contrasting conditions— and has allowed us to explore the differential expression patterns throughout the whole process. Our analysis has highlighted the rapid and complex genomic response of the brain associated with sex change, which is subsequently transmitted to the gonads, identifying a large number of candidate genes, some well-known and some novel, involved in the process. The present study provides strong evidence of the importance of the sex steroidogenic machinery during sex change in clownfish, with the aromatase gene playing a central role, both in the brain and the gonad. This work constitutes the first genome-wide study in a social sex-changing species and provides insights into the genetic mechanism governing social sex change and gonadal restructuring in protandrous hermaphrodites.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors would like to thank the Coastal and Marine Resources Core Lab, particularly Dave H. Pallet, for their invaluable support during fieldwork. We would like to express our gratitude to Tane Sinclair-Taylor and Camrin Braun for finding and tagging the clownfish families used in the present study and Paula R. Tamargo and Sonia Rábade for their assistance on histological processing. We also acknowledge helpful comments and advice from Prof. Laszlo Orban. We wish to thank Virginia A. Unkefer from the KAUST Academic Writing Services who assisted in the proof-reading of the manuscript. Figure 6 is courtesy of Ivan Gromicho (Academic Writing Services, KAUST, Thuwal, Saudi Arabia).