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Habilitation à diriger des recherches

Evolution & Systématique des algues rouges

Abstract : This manuscript of “Habilitation à Diriger des Recherches” recapitulates ten years of study centering on the diversity of red algae. My research focuses on many aspects of red algal evolution and relatedness toward the goal of evaluating and characterizing red algal biodiversity with the contribution of many collaborators. I am particularly interested in using an integrative approach towards systematics to assess evolutionary processes at both macroevolutionary and microevolutionary scales. A critical first step was to develop untested nuclear markers to improve the phylogenetic resolution among lineages of the Florideophyceae which led to considerable revisions of the classification of this subclass. This phylogenetic study served as a cornerstone to further study the evolutionary history of various taxa at the ordinal or generic level. I have supervised three PhD students and have two post-doctoral trainees working on red algal systematics. I supervised studies on the orders Sebdeniales and Halymeniales with post-doctoral trainee Toni Manghisi, on the Laurencia complex with two PhD students Julie Martin Lescanne and María Machín Sánchez and on the Corallinales with PhD student Lucie Bittner and post-doctoral fellow Viviana Peña Freire. In addition to this phylogenetic approach I contribute to floristic surveys in selected biogeographical regions (Atlantic and Mediterranean European coast, South Pacific, Indian Ocean) with my colleagues of the "phycological group" Florence Rousseau and Bruno de Reviers, as well as within the framework of the program "big expeditions" of the MNHN coordinated by Philippe Bouchet. These floristic studies, coupled with the acquisition and analysis of molecular data (the DNA barcode marker, as well as additional markers where required), allow us to better circumscribe algal species diversity. This approach has proven valuable in detecting cryptic species as well as species complexes and was recently applied to highlight exogenous species. Alexandre Geoffroy, a PhD student that I co-supervise with Christophe Destombe, detected the introduction of Polysiphonia morrowii, a species native to Asia, along the Brittany coasts using a DNA barcoding approach. As the data analysed becomes more comprehensive in terms of taxonomic, geographical and temporal coverage, I have begun tackling questions relating to the processes influencing speciation rates and distribution of marine algae. With the objective to supply tools for conservation biologists, we assess the congruence among scales (mainly taxonomic and spatial) to evaluate and monitor algal biodiversity of the Atlantic Coasts, within the framework of Marine Robuchon's doctoral thesis that I co-supervise with Myriam Valero. For the coherence of this document, I chose to discuss my research on phylogenetic relationships and species concepts within the red algae in an order from the root to the terminal leaves of the red algal phylogenetic tree. I present my own works and those of the students that I have I supervised.
Keywords : Phycology
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Submitted on : Tuesday, April 5, 2022 - 3:40:15 PM
Last modification on : Wednesday, September 28, 2022 - 4:20:12 PM
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Le Gall - 2012 - Etudes biolog...
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  • HAL Id : tel-03631355, version 1

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Line Le Gall. Evolution & Systématique des algues rouges. Biodiversité. Université Pierre & Marie Curie - Paris 6, 2012. ⟨tel-03631355⟩

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