title: GC content evolution in coding regions of angiosperm genomes: a unifying hypothesis.
abstract: In angiosperms (as in other species), GC content varies along and between genes, within a genome, and between genomes of different species, but the reason for this distribution is still an open question. Grass genomes are particularly intriguing because they exhibit a strong bimodal distribution of genic GC content and a sharp 5'-3' decreasing GC content gradient along most genes. Here, we propose a unifying model to explain the main patterns of GC content variation at the gene and genome scale. We argue that GC content patterns could be mainly determined by the interactions between gene structure, recombination patterns, and GC-biased gene conversion. Recent studies on fine-scale recombination maps in angiosperms support this hypothesis and previous results also fit this model. We propose that our model could be used as a null hypothesis to search for additional forces that affect GC content in angiosperms.
authors.affiliation: Institut des Sciences de l'Evolution de Montpellier, Unité Mixte de Recherche 5554, Centre National de la Recherche Scientifique, UMR 5554 CNRS, Université Montpellier 2, F-34095 Montpellier, France. Electronic address: sylvain.glemin@univ-montp2.fr.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Glémin
authors.affiliation: Institut des Sciences de l'Evolution de Montpellier, Unité Mixte de Recherche 5554, Centre National de la Recherche Scientifique, UMR 5554 CNRS, Université Montpellier 2, F-34095 Montpellier, France; Montpellier SupAgro, Unité Mixte de Recherche 1334 Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, F-34398 Montpellier, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Clément
authors.affiliation: Montpellier SupAgro, Unité Mixte de Recherche 1334 Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, F-34398 Montpellier, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: David
authors.affiliation: INRA, UMR de Génétique Végétale, INRA/CNRS/Univ Paris-Sud/AgroParistech, Ferme du Moulon, F-91190 Gif sur Yvette, France.
authors.forename: Adrienne
authors.initials: A
authors.lastname: Ressayre
mesh_terms: D001482:Base Composition; D019175:DNA Methylation; D019143:Evolution, Molecular; D018745:Genome, Plant; D019684:Magnoliopsida / Q000235:genetics* / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism; D016366:Open Reading Frames; D011995:Recombination, Genetic
chemical_list: D009707:Nucleosomes
keywords: GC biased gene conversion; GC content; angiosperm genomes; intron/exon structure; methylation; recombination