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| Gagnaire, Pierre-alexandre; Lamy, Jean-baptiste; Cornette, Florence; Heurtebise, Serge; Degremont, Lionel; Flahauw, Emilie; Boudry, Pierre; Bierne, Nicolas; Lapegue, Sylvie. |
| The Pacific cupped oyster is genetically subdivided into two sister taxa, Crassostrea gigas and C. angulata, which are in contact in the north-western Pacific. The nature and origin of their genetic and taxonomic differentiation remains controversial due the lack of known reproductive barriers and the high degree of morphologic similarity. In particular, whether the presence of ecological and/or intrinsic isolating mechanisms contributes to species divergence is unknown. The recent co-introduction of both taxa into Europe offers a unique opportunity to test how genetic differentiation is maintained under new environmental and demographic conditions. We generated a pseudo-chromosome assembly of the Pacific oyster genome using a combination of BAC-end... |
| Tipo: Text |
Palavras-chave: Cupped oysters; Genome assembly; Species divergence; Reproductive barriers; Recombination rate. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00455/56622/58337.pdf |
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| Gagnaire, Pierre-alexandre; Cornette, Florence; Heurtebise, Serge; Auge, M. T.; Bierne, Nicolas; Lapegue, Sylvie. |
| The cupped oysters Crassostrea angulata and Crassostrea gigas have been sequentially introduced in Europe from their native Pacific area for aquaculture purposes. Ongoing viral epidemic disease is responsible for large losses in oyster aquaculture production throughout Europe. In parallel with current efforts in developing selection programs for disease resistance, it becomes critically important to characterize genetic diversity patterns in both native and introduced areas. With the advent of next generation sequencing techniques, the power to resolve the fine-scale genetic structure at a genome-wide scale opens to new perspectives towards genetic resource management. Here, we present a genome-wide screen of genetic variation that combines SNP genotyping... |
| Tipo: Text |
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| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00167/27816/26009.pdf |
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| Lapegue, Sylvie; Heurtebise, Serge; Cornette, Florence; Guichoux, Erwan; Gagnaire, Pierre-alexandre. |
| The Pacific oyster, Crassostrea gigas, was voluntarily introduced from Japan and British Columbia into Europe in the early 1970s, mainly to replace the Portuguese oyster, Crassostrea angulata, in the French shellfish industry, following a severe disease outbreak. Since then, the two species have been in contact in southern Europe and, therefore, have the potential to exchange genes. Recent evolutionary genomic works have provided empirical evidence that C. gigas and C. angulata exhibit partial reproductive isolation. Although hybridization occurs in nature, the rate of interspecific gene flow varies across the genome, resulting in highly heterogeneous genome divergence. Taking this biological property into account is important to characterize genetic... |
| Tipo: Text |
Palavras-chave: Cupped oysters; Population genetics; Introgression; Conservation; Shellfisheries. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00623/73544/72938.pdf |
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| Faggion, Sara; Vandeputte, Marc; Chatain, Beatrice; Gagnaire, Pierre-alexandre; Allal, Francois. |
| Polygenic sex determination (PSD) may show variations in terms of genetic and environmental components between populations of fish species exposed/adapted to different environments. The 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. Here, 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). We found less females than males in the progeny, both in the global dataset (32.5%) and within each paternal group (from 25.1% for... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00464/57609/59864.pdf |
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| Duranton, Maud; Allal, Francois; Fraisse, Christelle; Bierne, Nicolas; Bonhomme, Francois; Gagnaire, Pierre-alexandre. |
| Speciation is a complex process that leads to the progressive establishment of reproductive isolation barriers between diverging populations. Genome-wide comparisons between closely related species have revealed the existence of heterogeneous divergence patterns, dominated by genomic islands of increased divergence supposed to contain reproductive isolation loci. However, this divergence landscape only provides a static picture of the dynamic process of speciation, during which confounding mechanisms unrelated to speciation can interfere. Here we use haplotype-resolved whole-genome sequences to identify the mechanisms responsible for the formation of genomic islands between Atlantic and Mediterranean sea bass lineages. Local ancestry patterns show that... |
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| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00446/55750/57409.pdf |
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| Gagnaire, Pierre-alexandre; Broquet, Thomas; Aurelle, Didier; Viard, Frederique; Souissi, Ahmed; Bonhomme, Francois; Arnaud-haond, Sophie; Bierne, Nicolas. |
| Estimating the rate of exchange of individuals among populations is a central concern to evolutionary ecology and its applications to conservation and management. For instance, the efficiency of protected areas in sustaining locally endangered populations and ecosystems depends on reserve network connectivity. The population genetics theory offers a powerful framework for estimating dispersal distances and migration rates from molecular data. In the marine realm, however, decades of molecular studies have met limited success in inferring genetic connectivity, due to the frequent lack of spatial genetic structure in species exhibiting high fecundity and dispersal capabilities. This is especially true within biogeographic regions bounded by well-known... |
| Tipo: Text |
Palavras-chave: Connectivity; Gene flow; Marine conservation; Population genomics; Population structure. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00275/38592/37120.pdf |
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| Rey, Carine; Darnaude, Audrey; Ferraton, Franck; Guinand, Bruno; Bonhomme, François; Bierne, Nicolas; Gagnaire, Pierre-alexandre. |
| Understanding the genetic underpinnings of fitness trade-o s across spatially variable environments remains a major challenge in evolutionary biology. In Mediterranean gilthead sea bream, first-year juveniles use various marine and brackish lagoon nursery habitats characterized by a trade-o between food availability and environmental disturbance. Phenotypic di erences among juveniles foraging in di erent habitats rapidly appear after larval settlement, but the relative role of local selection and plasticity in phenotypic variation remains unclear. Here, we combine phenotypic and genetic data to address this question. We first report correlations of opposite signs between growth and condition depending on juvenile habitat type. Then, we use single... |
| Tipo: Text |
Palavras-chave: Antagonistic pleiotropy; Habitat association; Fitness trade-off; Juvenile growth; Polygenic scores; RAD-sequencing; Spatially varying selection. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00622/73370/72560.pdf |
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