Population-specific variations of the genetic architecture of sex determination in wild European sea bass Dicentrarchus labrax L.

• Published in: Heredity
• Main Authors: FAGGION, SARA, Vandeputte Marc, Chatain Beatrice, Gagnaire Pierre-Alexandre, Allal François
• Other Authors: Faggion, Sara, Vandeputte, Marc, Chatain, Beatrice, Gagnaire, Pierre-Alexandre, Allal, François
• Format: Article in Journal/Newspaper
• Language: English
• Published: SpringerNature 2018
• Subjects: European sea bass; polygenic sex determination; wGWAS; North Atlantic
• Online Access: http://hdl.handle.net/11577/3276744; https://doi.org/10.1038/s41437-018-0157-z; https://www.nature.com/articles/s41437-018-0157-z

Among the different sex determination modalities exhibited by fish species, polygenic sex determination (PSD) may show variations in terms of genetic and environmental components between populations exposed/adapted to different environments. European sea bass (Dicentrarchus labrax) is an interesting model, combining both a PSD system and a genetic subdivision into an Atlantic and a Mediterranean lineage, with genetic substructures within the Mediterranean Sea. We produced experimental progeny crosses (N = 927) from broodstock sampled in four wild populations (North Atlantic, NAT; Western Mediterranean, WEM; North-Eastern Mediterranean, NEM; South-Eastern Mediterranean, SEM). There were less females than males in the progeny, both in the global dataset (32.5%) and within each paternal group (from 25.1% for NEM to 39.0% for WEM), with significant variation among populations, dams and sires. Sex, body weight (BW) and body length (BL) showed moderate heritability (0.52 ± 0.17, 0.46 ± 0.17, 0.34 ± 0.15, respectively). Sex was genetically correlated with BW and BL (rA sex/BW = 0.69 ± 0.12, rA sex/BL = 0.66 ± 0.13). The wGWAS performed both on the global dataset and within each paternal group revealed a different genetic architecture of sex determination between Atlantic and Mediterranean populations (9 QTLs found in NAT, 7 in WEM, 5 in NEM and 4 in SEM, with a cumulated variance explained of 27.04%, 21.87%, 15.89% and 12.10%, respectively) with a more similar genetic architecture among geographically close populations compared to geographically distant populations, consistent with the hypothesis of a population-specific evolution of polygenic sex determination systems in different environments.