Showing papers by "Jean Weissenbach published in 2013"
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Pierre-and-Marie-Curie University1, University of Évry Val d'Essonne2, French Alternative Energies and Atomic Energy Commission3, Centre national de la recherche scientifique4, Alfred Wegener Institute for Polar and Marine Research5, University of Ostrava6, Queen's University Belfast7, University of Rennes8, Pompeu Fabra University9, University of Oslo10, Scottish Association for Marine Science11, American University in Cairo12, University of Freiburg13, University of Marburg14
TL;DR: An evolutionary scenario involving an ancestral red alga that was driven by early ecological forces to lose genes, introns, and intergenetic DNA is proposed; this loss was followed by an expansion of genome size as a consequence of activity of transposable elements.
Abstract: Red seaweeds are key components of coastal ecosystems and are economically important as food and as a source of gelling agents, but their genes and genomes have received little attention. Here we report the sequencing of the 105-Mbp genome of the florideophyte Chondrus crispus (Irish moss) and the annotation of the 9,606 genes. The genome features an unusual structure characterized by gene-dense regions surrounded by repeat-rich regions dominated by transposable elements. Despite its fairly large size, this genome shows features typical of compact genomes, e.g., on average only 0.3 introns per gene, short introns, low median distance between genes, small gene families, and no indication of large-scale genome duplication. The genome also gives insights into the metabolism of marine red algae and adaptations to the marine environment, including genes related to halogen metabolism, oxylipins, and multicellularity (microRNA processing and transcription factors). Particularly interesting are features related to carbohydrate metabolism, which include a minimalistic gene set for starch biosynthesis, the presence of cellulose synthases acquired before the primary endosymbiosis showing the polyphyly of cellulose synthesis in Archaeplastida, and cellulases absent in terrestrial plants as well as the occurrence of a mannosylglycerate synthase potentially originating from a marine bacterium. To explain the observations on genome structure and gene content, we propose an evolutionary scenario involving an ancestral red alga that was driven by early ecological forces to lose genes, introns, and intergenetic DNA; this loss was followed by an expansion of genome size as a consequence of activity of transposable elements.
299 citations