Transposons and the Dynamic Genome

ISBN-13: 9783642242526 / Angielski / Miękka / 2011 / 184 str.

Dirk-Henner Lankenau; Jean-Nicolas Volff

Opis

It will be some time beforewe see Relax, there's nothing wrong with the "slime, protoplasm, &c. "generating transpositionpaper. People aren't a new animal. ButI have long readyforthisyet. Istopped publishing regretted that I truckled to public in refereed journals in 1965 because opinion, andusedthePentateuchal therewas nointerest in themaize term of creation, by which I really controlling elements. meant "appeared" by some wholly Barbara McClintockto Mel Green, unknownprocess. It is mere rubbish, 1969 thinking at presentof theorigin of life; onemight as well think of the originof matter. Charles Darwin to James D. Hooker, March29, 1863 Sometimes my students and others have asked me: "what was ?rst in evo- tion - retroviruses or retrotransposons?" Since HowardTemin proposed that retrovirusesevolvedfromretrotransposons(Temin1980;Teminetal. 1995)the other alternative that retroviruses emerged ?rst and were the predecessors of LTR-retrotransposons has since been a controversial issue (Terzian et al., this BOOK). While DNA-transposons could not have existed in an ancestral R- world by de?nition, sure enough, some arguments de?nitely point towards apre-DNAworldscenarioinwhichretroelementswerethedirectdescendants of the earliest replicators representing the emergence of life. First, these rep- cators likely catalyzed their own or other's replication cycles via the catalytic properties of RNA molecules. After translation had emerged some replicators possibly encoded an RNA polymerase ?rst. This later evolved into reverse transcriptase(RT), i. e. themostprominentkey-factoratthetransitionintothe DNA world. Simultaneously, replicators could also have encoded membrane protein-genessuchastheenvgeneofrecentDNA-proviruses. Membraneswere likely present muchearlier as prebioticoily ?lms that supported theevolution of a prebiotic-protometabolism (Dyson 1999; Grif?ths 2007).

Spis treści

Theoretical Approaches to the Dynamics of Transposable Elements in Genomes, Populations, and Species.- Infra- and Transspecific Clues to Understanding the Dynamics of Transposable Elements.- Morphological Characters from the Genome: SINE Insertion Polymorphism and Phylogenies.- Genome Defense Against Transposable Elements and the Origins of Regulatory RNA.- When Drosophila Meets Retrovirology: The gypsy Case.- Transposon–Host Cell Interactions in the Regulation of Sleeping Beauty Transposition.- Interactions of Transposons with the Cellular DNA Repair Machinery.

Blurb

There are only few major key functions that lie beneath the fundamental architecture of metabolism and life. These are multiplication, variation and heredity. Only if these factors interact synergistically can Darwinian selection power the evolution of biodiversity. Transposable elements have always played a major role in this process. The genomes of all organisms consist of chromosomes that are built up of double-stranded nucleic acid chains on whose stability and integrity the existence of cells depend. While DNA repair warrants the chemical integrity of DNA and protects it from metabolic and environmental mutagens, meiotic recombination and transposable element activity appear to counteract the molecular guardians of genome stability. Transposable elements and their kind often make up the bulk of genomic DNA, often approaching 50% of the genome. By contrast, the classic genes represent as little as 1.8% of genomic DNA, in case of the human genome.

This volume gives an overview on mobile DNA and how such contradiction to the obligatory stability of genomes can be understood. Obviously, an understanding can only be achieved by cutting deeply into the evolutionary history of life along with the evolution of transposable elements and dynamic genomes.

This book therefore also celebrates Charles Darwin’s 200^th birthday. The reader is challenged to view the role of movable DNA along historical roots from the levels of cells to populations to biological species integrating the accompanying molecular evolution of host, cell and genome interaction. One will witness even the reactivation of a long since dead, fossil transposable element and the infection of germline cells by the first established, mobile and endogenous insect retrovirus.