Browsing by Author "Mauger, Stephane"

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    Pre-domestication bottlenecks of the cultivated seaweed Gracilaria chilensis
    (2022) Huanel, Oscar R.; Quesada-Calderon, Suany; Molina, Cristian Rios; Morales-Gonzalez, Sarai; Saenz-Agudelo, Pablo; Nelson, Wendy A.; Arakaki, Natalia; Mauger, Stephane; Faugeron, Sylvain; Guillemin, Marie-Laure
    Gracilaria chilensis is the main cultivated seaweed in Chile. The low genetic diversity observed in the Chilean populations has been associated with the over-exploitation of natural beds and/or the founder effect that occurred during post-glacial colonization from New Zealand. How these processes have affected its evolutionary trajectory before farming and incipient domestication is poorly understood. In this study, we used 2232 single nucleotide polymorphisms (SNPs) to assess how the species' evolutionary history in New Zealand (its region of origin), the founder effect linked to transoceanic dispersion and colonization of South America, and the recent over-exploitation of natural populations have influenced the genetic architecture of G. chilensis in Chile. The contrasting patterns of genetic diversity and structure observed between the two main islands in New Zealand attest to the important effects of Quaternary glacial cycles on G. chilensis. Approximate Bayesian Computation (ABC) analyses indicated that Chatham Island and South America were colonized independently near the end of the Last Glacial Maximum and emphasized the importance of coastal and oceanic currents during that period. Furthermore, ABC analyses inferred the existence of a recent and strong genetic bottleneck in Chile, matching the period of over-exploitation of the natural beds during the 1970s, followed by rapid demographic expansion linked to active clonal propagation used in farming. Recurrent genetic bottlenecks strongly eroded the genetic diversity of G. chilensis prior to its cultivation, raising important challenges for the management of genetic resources in this incipiently domesticated species.
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    The Rhodoexplorer Platform for Red Algal Genomics and Whole-Genome Assemblies for Several Gracilaria Species
    (2023) Lipinska, Agnieszka P.; Krueger-Hadfield, Stacy A.; Godfroy, Olivier; Dittami, Simon M.; Ayres-Ostrock, Ligia; Bonthond, Guido; Brillet-Gueguen, Loraine; Coelho, Susana; Corre, Erwan; Cossard, Guillaume; Destombe, Christophe; Epperlein, Paul; Faugeron, Sylvain; Ficko-Blean, Elizabeth; Beltran, Jessica; Lavaut, Emma; Le Bars, Arthur; Marchi, Fabiana; Mauger, Stephane; Michel, Gurvan; Potin, Philippe; Scornet, Delphine; Sotka, Erik E.; Weinberger, Florian; de Oliveira, Mariana Cabral; Guillemin, Marie-Laure; Plastino, Estela M.; Valero, Myriam
    Macroalgal (seaweed) genomic resources are generally lacking as compared with other eukaryotic taxa, and this is particularly true in the red algae (Rhodophyta). Understanding red algal genomes is critical to understanding eukaryotic evolution given that red algal genes are spread across eukaryotic lineages from secondary endosymbiosis and red algae diverged early in the Archaeplastids. The Gracilariales is a highly diverse and widely distributed order including species that can serve as ecosystem engineers in intertidal habitats and several notorious introduced species. The genus Gracilaria is cultivated worldwide, in part for its production of agar and other bioactive compounds with downstream pharmaceutical and industrial applications. This genus is also emerging as a model for algal evolutionary ecology. Here, we report new whole-genome assemblies for two species (Gracilaria chilensis and Gracilaria gracilis), a draft genome assembly of Gracilaria caudata, and genome annotation of the previously published Gracilaria vermiculophylla genome. To facilitate accessibility and comparative analysis, we integrated these data in a newly created web-based portal dedicated to red algal genomics (https://rhodoexplorer.sb-roscoff.fr). These genomes will provide a resource for understanding algal biology and, more broadly, eukaryotic evolution.