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| Becheler, Ronan; Masson, Jean-pierre; Arnaud-haond, Sophie; Halkett, Fabien; Mariette, Stephanie; Guillemin, Marie-laure; Valero, Myriam; Destombe, Christophe; Stoeckel, Solenn. |
| Partial clonality is commonly used in Eukaryotes and has large consequences for their evolution and ecology. Assessing accurately the relative importance of clonal versus sexual reproduction matters for studying and managing such species. Here, we proposed a Bayesian approach, ClonEstiMate, to infer rates of clonality c from populations sampled twice over a short time interval, ideally one generation time. The method relies on the likelihood of the transitions between genotype frequencies of ancestral and descendent populations, using an extended Wright-Fisher model explicitly integrating reproductive modes. Our model provides posterior probability distribution of inferred c, given the assumed rates of mutation, as well as inbreeding and selfing when... |
| Tipo: Text |
Palavras-chave: Inbreeding; Instantaneous inference; Population genetics model; Rate of asexuality; Selfing. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00390/50187/50810.pdf |
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| Chapelle, Annie; Le Bec, Claude; Amzil, Zouher; Dreanno, Catherine; Guillou, Laure; Klouch, Khadidja; Labry, Claire; Le Gac, Mickael; Pineau-guillou, Lucia; Siano, Raffaele; Abernot, Chantal; Andrieux, Francoise; Caradec, Florian; Destombe, Christophe; Dia, A.; Doner, Anne; Duval, Julia; Gouriou, Jeremie; Lazure, Pascal; Le Brun, Luc; Le Gal, Dominique; Malestroit, Pascale; Petton, Sebastien; Plus, Martin; Quere, Julien; Savar, Veronique; Schmitt, Sophie; Terre, A.; Youenou, Agnes. |
| Suite à l’événement de grande ampleur d’efflorescence d’Alexandrium minutum et des toxicités associées en Rade de Brest en 2012, un projet a été élaboré avec la Région Bretagne dans le cadre du développement du port de Brest. L’Ifremer a organisé un échantillonnage dans l’estuaire de la rivière de Daoulas, zone la plus touchée en 2012, au cours des printemps-été 2013 et 2014. Un suivi de la présence d’A. minutum dans les sédiments a également été réalisé en hiver 2014. De ces suivis, des mesures réalisées au laboratoire à ce jour, des simulations du modèle Prévimer ainsi que des résultats du réseau Rephy et Velyger, il ressort que: * La rade de Brest peut aujourd’hui être considérée comme une zone à risque pour Alexandrium minutum. En effet, depuis 2012... |
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| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00254/36487/35029.pdf |
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| Le Gac, Mickael; Metegnier, Gabriel; Chomerat, Nicolas; Malestroit, Pascale; Quere, Julien; Bouchez, Olivier; Siano, Raffaele; Destombe, Christophe; Guillou, Laure; Chapelle, Annie. |
| Understanding divergence in the highly dispersive and seemingly homogeneous pelagic environment for organisms living as free drifters in the water column remains a challenge. Here, we analyzed the transcriptome wide mRNA sequences, as well as the morphology of 18 strains of Alexandrium minutum, a dinoflagellate responsible for Harmful Algal Blooms worldwide, to investigate the functional bases of a divergence event. Analysis of the joint site frequency spectrum (JSFS) pointed toward an ancestral divergence in complete isolations followed by a secondary contact resulting in gene flow between the two diverging groups, but heterogeneous across sites. The sites displaying fixed SNPs were associated with a highly restricted gene flow and a strong... |
| Tipo: Text |
Palavras-chave: Dinoflagellates; Harmful algal blooms; Populations Genomics; Pseudocryptic species; Speciation. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00347/45857/45529.pdf |
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| Pante, Eric; Puillandre, Nicolas; Viricel, Amélia; Arnaud-haond, Sophie; Aurelle, Didier; Castelin, Magalie; Chenuil, Anne; Destombe, Christophe; Forcioli, Didier; Valero, Myriam; Viard, Frederique; Samadi, Sarah. |
| Connectivity among populations determines the dynamics and evolution of populations, and its assessment is essential in ecology in general and in conservation biology in particular. The robust basis of any ecological study is the accurate delimitation of evolutionary units, such as populations, metapopulations and species. Yet a disconnect still persists between the work of taxonomists describing species as working hypotheses and the use of species delimitation by molecular ecologists interested in describing patterns of gene flow. This problem is particularly acute in the marine environment where the inventory of biodiversity is relatively delayed, while for the past two decades, molecular studies have shown a high prevalence of cryptic species. In this... |
| Tipo: Text |
Palavras-chave: Connectivity; Marine organisms; Molecular systematics; Taxonomy. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00248/35952/35301.pdf |
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| Metegnier, Gabriel; Paulino, Sauvann; Ramond, Pierre; Siano, Raffaele; Sourisseau, Marc; Destombe, Christophe; Le Gac, Mickael. |
| Harmful algal blooms are caused by specific members of microbial communities. Understanding the dynamics of these events requires comparing the strategies developed by the problematic species to cope with environmental fluctuations to the ones developed by the other members of the community. During three consecutive years, the meta-transcriptome of micro-eukaryote communities was sequenced during blooms of the toxic dinoflagellate Alexandrium minutum. The dataset was analyzed to investigate species specific gene expression dynamics. Major shifts in gene expression were explained by the succession of different species within the community. Although expression patterns were strongly correlated with fluctuation of the abiotic environment, and more... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00622/73390/72602.pdf |
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