title: Non-functional genes repaired at the RNA level.
abstract: Genomes and genes continuously evolve. Gene sequences undergo substitutions, deletions or nucleotide insertions; mobile genetic elements invade genomes and interleave in genes; chromosomes break, even within genes, and pieces reseal in reshuffled order. To maintain functional gene products and assure an organism's survival, two principal strategies are used - either repair of the gene itself or of its product. I will introduce common types of gene aberrations and how gene function is restored secondarily, and then focus on systematically fragmented genes found in a poorly studied protist group, the diplonemids. Expression of their broken genes involves restitching of pieces at the RNA-level, and substantial RNA editing, to compensate for point mutations. I will conclude with thoughts on how such a grotesquely unorthodox system may have evolved, and why this group of organisms persists and thrives since tens of millions of years.
authors.affiliation: Department of Biochemistry, Robert-Cedergren Centre for Bioinformatics and Genomics, Université de Montréal, Montréal, Canada. Electronic address: Gertraud.Burger@umontreal.ca.
authors.forename: Gertraud
authors.initials: G
authors.lastname: Burger
mesh_terms: D000818:Animals; D005075:Biological Evolution; D053938:DNA Fragmentation; D050259:Genes, Mitochondrial / Q000235:genetics; D005823:Genetics / Q000639:trends*; D006801:Humans; D012313:RNA / Q000235:genetics*; D017393:RNA Editing; D052416:Targeted Gene Repair
chemical_list: D012313:RNA
keywords: Diplonemids; Diplonémides; Evolution of complexity; Gene fragmentation; Gènes fragmentés; Insertion and substitution RNA editing; Protistes; Protists; Trans-splicing; Édition de l’ARN par insertion et substitution; Épissage en trans; Évolution de la complexité