Does natural selection explain the fine scale genetic structure at the nuclear exon Glu-5' in blue mussels from Kerguelen ?

• Published in: Ecology and Evolution
• Main Authors: Gerard, K, Roby, C, Bierne, N, Borsa, Philippe, Féral, J.-P, Chenuil, A.
• Other Authors: Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE), Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement IRD : UMR237-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS), Biocomplexité des écosystèmes coralliens de l'Indo-Pacifique (CoReUS2), Institut de Recherche pour le Développement (IRD)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2015
• Subjects: F-statistics; AMOVA; mac-1; neutral structure; environment; local adaptive differentiation; [SDV.GEN.GPO]Life Sciences [q-bio]/Genetics/Populations and Evolution [q-bio.PE]; Southern Ocean
• Online Access: https://ird.hal.science/ird-01366543; https://ird.hal.science/ird-01366543/document; https://ird.hal.science/ird-01366543/file/MYTILUSGerard-et-al-2015-EcolEvol_p%20HAL_vff.pdf; https://doi.org/10.1002/ece3.1421

International audience The Kerguelen archipelago, isolated in the Southern Ocean, shelters a blue mussel Mytilus metapopulation far from any influence of continental populations or any known hybrid zone. The finely carved coast leads to a highly heterogeneous habitat. We investigated the impact of the environment on the genetic structure in those Kerguelen blue mussels by relating allele frequencies to habitat descriptors. A total sample comprising up to 2248 individuals from 35 locations was characterized using two nuclear markers, mac-1 and Glu-5’, and a mitochondrial marker (COI). The frequency data from 9 allozyme loci in 9 of these locations were also reanalysed. Two other nuclear markers (EFbis and EFprem’s) were monomorphic. Compared to Northern-Hemisphere populations, polymorphism in Kerguelen blue mussels was lower for all markers except for the exon Glu-5’. At Glu-5’, genetic differences were observed between samples from distinct regions (FCT=0.077), as well as within two regions, including between samples separated by less than 500 meters. No significant differentiation was observed in the AMOVA analyses at the two other markers (mac-1 and COI). Like mac-1, all allozyme loci genotyped in a previous publication, displayed lower differentiation (Jost's D) and FST values than Glu-5'. Power simulations and confidence intervals support that Glu-5’ displays significantly higher differentiation than the other loci (except a single allozyme for which confidence intervals overlap). AMOVA analyses revealed significant effects of the giant kelp Macrocystis and wave exposure on this marker. We discuss the influence of hydrological conditions on the genetic differentiation among regions. In marine organisms with high fecundity and high dispersal potential, gene flow tends to erase differentiation, but this study showed significant differentiation at very small distance. This may be explained by the particular hydrology and the carved coastline of the Kerguelen archipelago, together with spatially variable ...