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| Registros recuperados: 33 | |
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| Bailleul, Diane; Mackenzie, Alicia; Sacchi, Olivier; Poisson, Francois; Bierne, Nicolas; Arnaud-haond, Sophie. |
| The blue shark Prionace glauca, among the most common and widely studied pelagic sharks, is a top predator, exhibiting the widest distribution range. However, little is known about its population structure and spatial dynamics. With an estimated removal of 10 to 20 million individuals per year by fisheries, the species is classified as “Near Threatened” by International Union for Conservation of Nature. We lack the knowledge to forecast the long-term consequences of such a huge removal on this top predator itself and on its trophic network. The genetic analysis of more than 200 samples collected at broad scale (from Mediterranean Sea, North Atlantic and Pacific Oceans) using mtDNA and nine microsatellite markers allowed to detect signatures of genetic... |
| Tipo: Text |
Palavras-chave: Blue shark; Conservation; Fisheries; Genetic panmixia; Prionace glauca; Stock. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00417/52866/53776.pdf |
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| Bierne, Nicolas; Bezuart, Ivan; Vonau, Vincent; Bonhomme, François; Bedier, Edouard. |
| Correlation between DNA microsatellite heterozygosity and growth rate was investigated in two hatchery-propagated stocks of the shrimp Penaeus stylirostris, which had been genetically isolated from wild founders for 17 generations, and from each other for five more generations. presumed demographic history of these populations suggested that they were maintained at small effective population sizes. and this was confirmed by significant changes in allelic frequencies between the two stocks. Despite a small sample size (n = 60) and a small number of loci screened, a significant positive correlation was detected between microsatellite tri-locus heterozygosity and growth rate in one of the two stocks (r = 0.3, P = 0.02). In the other stock (n = 48), the... |
| Tipo: Text |
Palavras-chave: Penaeus stylirostris; Heterozygosity; Marker associated heterosis; Inbreeding depression; Microsatellites. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/2000/publication-753.pdf |
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| Bierne, Nicolas; Boudry, Pierre; Lapegue, Sylvie; Bonhomme, Francois; Faure, M; Sauvage, Christopher; Moraga, D; Boutet, Isabelle; David, Elise; Jollivet, Didier; Tanguy, Arnaud; Faure, Baptiste; David, Patrice. |
| For a long time, population geneticists have had to content themselves with analysing neutral markers to infer selection processes indirectly. The recent improvement of sequencing tools now enables them to analyse the variations of a large number of genes and therefore to spot the genes, or the amino acids, which are under the direct influence of the selection (Yang & Bielawski, 2000). In order to analyse the selection processes acting on the mutations and discriminate the different factors acting on their evolution (genetic selection or drift), it is essential to compare polymorphism data between genomes of the same species/population and divergence data between species/populations (Kimura, 1983). Recently, polymorphism data has become available for a... |
| Tipo: Text |
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| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/rapport-6489.pdf |
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| Bierne, Nicolas; David, Pierre; Langlade, Aime; Bonhomme, F. |
| Maintaining the integrity of differentiated genomes in marine organisms needs efficient isolation mechanisms, because planktonic larval dispersion provides contacts between taxa. Habitat specialisation is interesting in this respect, because it can both prevent interspecific crosses (each taxon reproduces in its own habitat) and eliminate hybrids (typically less fit than a parental taxon in each habitat). The contact zone between smooth-shelled mussels Mytilus edulis and M. galloprovincialis in Europe is a good example, as allozyme genotypes typical of both taxa seem to segregate into different habitats. However, allozymes may be selected directly and it is not known whether the same pattern can be extended to the whole genome. Here, we used 6 presumably... |
| Tipo: Text |
Palavras-chave: Habitat specialisation; Hybrid zone; Introgression; Mytilus edulis; Mytilus galloprovincialis. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00000/10228/7597.pdf |
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| Bierne, Nicolas; Eyre Walker, A. |
| A strong negative correlation between the rate of amino-acid substitution and codon usage bias in Drosophila has been attributed to interference between positive selection at nonsynonymous sites and weak selection on codon usage. To further explore this possibility we have investigated polymorphism and divergence at three kinds of sites: synonymous, nonsynonymous and intronic in relation to codon bias in D. melanogaster and D. simulans. We confirmed that protein evolution is one of the main explicative parameters for interlocus codon bias variation (r(2) similar to 40%). However, intron or synonymous diversities, which could have been expected to be good indicators of local interference [here defined as the additional increase of drift due to selection on... |
| Tipo: Text |
Palavras-chave: Substitution rate; Selective constraints; Linkage; Hill Robertson interference; GC content; Drosophila; Diversity; Codon usage. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-4221.pdf |
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| Bierne, Nicolas; Tanguy, A; Faure, Michel; Faure, B; David, E; Boutet, I; Boon, E; Quere, N; Plouviez, S; Kemppainen, P; Jollivet, D; Moraga, D; Boudry, Pierre; David, P. |
| We describe a simple protocol to reduce the number of cloning reactions of nuclear DNA sequences in population genetic studies of diploid organisms. Cloning is a necessary step to obtain correct haplotypes in such organisms, and, while traditional methods are efficient at cloning together many genes of a single individual, population geneticists rather need to clone the same locus in many individuals. Our method consists of marking individual sequences during the polymerase chain reaction (PCR) using 5'-tailed primers with small polynucleotide tags. PCR products are mixed together before the cloning reaction and clones are sequenced with universal plasmid primers. The individual from which a sequence comes from is identified by the tag sequences upstream... |
| Tipo: Text |
Palavras-chave: Sequence; Population genetics; High throughput allele recognition; DNA polymorphism. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-4222.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... |
| Tipo: Text |
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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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| 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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| 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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| Harrang, Estelle; Bierne, Nicolas; Heurtebise, Serge; Morga, Benjamin; Lapegue, Sylvie. |
| L'huître plate européenne Ostrea edulis a connu une période faste dans l'aquaculture jusqu'à la fin des années 1960, lorsque deux parasites, Marteilia refringens (1969) et Bonamia ostreae (1979), ont successivement décimé les bancs naturels de cette espèce endémique, déjà affaiblis par la sur-exploitation de ses gisements. Historiquement présente sur toute la côte européenne, de la Mer du Nord à la Mer Méditerranée, en passant par l'Océan Atlantique, la Mer Adriatique et la Mer Noire, les bancs naturels de cette espèce sont devenus très localisés, laissant penser à des phénomènes d'adaptation locale de l'huître vis à vis de son environnement biotique et abiotique. La diversité et la structuration génétique de plusieurs populations de l'espèce, à l'échelle... |
| Tipo: Text |
Palavras-chave: Huître plate; Ostrea edulis; Génétique des populations; Sélection Génétique. |
| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00014/12547/9417.pdf |
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| Harrang, Estelle; Lapegue, Sylvie; Morga, Benjamin; Bierne, Nicolas. |
| Marine bivalves show among the greatest allozyme diversity ever reported in Eukaryotes, putting them historically at the heart of the neutralist-selectionist controversy on the maintenance of genetic variation. Although it is now acknowledged that this high diversity is most probably a simple consequence of a large population size, convincing support for this explanation would require a rigorous assessment of the silent nucleotide diversity in natural populations of marine bivalves, which has not yet been done. This study investigated DNA sequence polymorphism in a set of 37 nuclear loci in wild samples of the flat oyster Ostrea edulis. Silent diversity was found to be only moderate (0.7%), and there was no departure from demographic equilibrium under the... |
| Tipo: Text |
Palavras-chave: Nucleotide; Polymorphism; Marine bivalve; Deleterious; Mutations; Genetic load; Ostrea edulis. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00125/23610/21444.pdf |
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| Masseret, Estelle; Bierne, Nicolas; Chevret, Pascale; Roumagnac, Marie; Bec, Béatrice; Laugier, Thierry; Collos, Yves; Vaquer, Andre. |
| Coastal lagoons are morphologically and ecologically complex ecosystems, subject to constantly changing environmental conditions generally of much greater magnitude than it is recorded in the open sea. Due to their transitional nature, they usually display a number of specific features (ie. high nutrient concentrations, light spectral quality, salinity range) which are potentially influencing strategies of adaptation of photosynthetic microorganisms. The unicellular cyanobacteria Synechococcus is a major component of marine and freshwater picophytoplankton. Its genetic diversity is well documented for these ecosystems, but knowledge about biodiversity and distribution of this genus in transitional waters remains scarce. The phylogenetic analysis of a... |
| Tipo: Text |
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| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/00011/12198/8960.pdf |
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| Pepin, Jean-francois; Benabdelmouna, Abdellah; Bierne, Nicolas; Chasselin, Leo; Degremont, Lionel; Guesdon, Stephane; Lamy, Jean-baptiste; Le Moine, Olivier; Normand, Julien; Robert, Stephane; Soletchnik, Patrick. |
| Depuis 2014, des épisodes de mortalité anormale affectent les cheptels mytilicoles tant adultes que juvéniles. Dès l’année 2015, une étude spécifique cofinancée par la DPMA et réalisée par l’Ifremer a été initiée, l’action de recherche MORBLEU (Mortalité des moules Bleues). Les années 2015- 2017 ont permis de dégager des éléments de connaissance et des pistes relatifs aux facteurs biotiques et abiotiques qui semblent intervenir dans le phénomène de hausse de mortalité des moules depuis 2014. Pour l’année 2018, les actions d’observation et de suivis du milieu et des moules ont été fortement réduites et trois axes principaux ont été poursuivis : i) l’étude de la relation entre l’évolution des équilibres microbiens planctoniques et l’apparition de mortalités... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00588/70056/67999.pdf |
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| Registros recuperados: 33 | |
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