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Quéré N, Desmarais E, Tsigenopoulos CS, Belkhir K, Bonhomme F, Guinand B. Gene flow at major transitional areas in sea bass (Dicentrarchus labrax) and the possible emergence of a hybrid swarm. Ecol Evol 2012; 2:3061-78. [PMID: 23301173 PMCID: PMC3539001 DOI: 10.1002/ece3.406] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 09/18/2012] [Accepted: 09/25/2012] [Indexed: 11/08/2022] Open
Abstract
The population genetic structure of sea bass (Dicentrarchus labrax) along a transect from the Atlantic Ocean (AO) to the Eastern Mediterranean (EM) Sea differs from that of most other marine taxa in this area. Three populations (AO, Western Mediterranean [WM], EM) are recognized today, which were originally two allopatric populations. How two ancestral genetic units have evolved into three distinct units has not been addressed yet. Therefore, to investigate mechanisms that lead to the emergence of the central WM population, its current status, and its connectivity with the two parental populations, we applied 20 nuclear loci that were either gene associated or gene independent. Results confirmed the existence of three distinct gene pools, with higher differentiation at two transitional areas, the Almeria-Oran Front (AOF) and of the Siculo-Tunisian Strait (STS), than within any population. Significant linkage disequilibrium and heterozygote excess indicated that the STS is probably another tension zone, as already described for the AOF. Neutrality tests fail to reveal marker loci that could be driven by selection within or among metapopulations, except for locus DLA0068. Collectively, results support that the central WM population arose by trapping two tensions zones at distinct geographic locations of limited connectivity. Population assignment further revealed that WM individuals were more introgressed than individuals from the other two metapopulations. This suggests that this population might result from hybrid swarming, and was or is still seeded by genes received through the filter of each tension zone.
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Affiliation(s)
- Nolwenn Quéré
- Institut des Sciences de l'Évolution de Montpellier, CNRS-UMR 5554, Université Montpellier 2cc63, 34095, Montpellier Cedex 5, France
- Station Méditerranéenne de l'Environnement Littoral2 Avenue des chantiers, 34200, Sète, France
| | - Erick Desmarais
- Institut des Sciences de l'Évolution de Montpellier, CNRS-UMR 5554, Université Montpellier 2cc63, 34095, Montpellier Cedex 5, France
- LabEx CeMEB, Université Montpellier IIplace E. Bataillon, cc63, 34095, Montpellier Cedex 5, France
| | - Costas S Tsigenopoulos
- Hellenic Center for Marine Research, Institute of Marine Biology and GeneticsPO Box 2214, Gournes Pediados, 71500, Heraklion, Crete, Greece
| | - Khalid Belkhir
- Institut des Sciences de l'Évolution de Montpellier, CNRS-UMR 5554, Université Montpellier 2cc63, 34095, Montpellier Cedex 5, France
| | - François Bonhomme
- Institut des Sciences de l'Évolution de Montpellier, CNRS-UMR 5554, Université Montpellier 2cc63, 34095, Montpellier Cedex 5, France
- Station Méditerranéenne de l'Environnement Littoral2 Avenue des chantiers, 34200, Sète, France
| | - Bruno Guinand
- Institut des Sciences de l'Évolution de Montpellier, CNRS-UMR 5554, Université Montpellier 2cc63, 34095, Montpellier Cedex 5, France
- Station Méditerranéenne de l'Environnement Littoral2 Avenue des chantiers, 34200, Sète, France
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SADEDIN S, HOLLANDER J, PANOVA M, JOHANNESSON K, GAVRILETS S. Case studies and mathematical models of ecological speciation. 3: Ecotype formation in a Swedish snail. Mol Ecol 2009; 18:4006-23. [DOI: 10.1111/j.1365-294x.2009.04320.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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