Karakterizacija pokretnih genetičkih elemenata koji sadrže uzastopno ponovljene nizove u pacifičke kamenice Crassostrea gigas (Thunberg, 1793)

doctoral thesis

• Title (english): Characterisation of transposable elements containing internal tandem repeats in the pacific oyster Crassostrea gigas (Thunberg, 1793)
• Author: Tanja Vojvoda Zeljko
• Mentor: Miroslav Plohl (mentor)
• Committee member: Branka Bruvo Mađarić (član povjerenstva)
• Committee member: Damjan Franjević (član povjerenstva)
• Committee member: Jasna Lajtner (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2015, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology
• Universal decimal classification (UDC): 575 - General genetics. General cytogenetics

Abstract

Uzastopno i raspršeno ponovljene sekvence sačinjavaju velik dio eukariotskih genoma, pa tako i genoma školjkaša (razred Bivalvia). Nedavno sekvencirani genom pacifičke kamenice Crassostrea gigas pokazuje visok udio ponovljenih sekvenci od 36 %. Bioinformatičkom pretragom genoma u ovom je radu izdvojeno 10 najzastupljenijih tipova uzastopno ponovljenih sekvenci. S obzirom na duljinu monomera tipičnu za satelitne DNA te mogućnost stvaranja dugačkih nizova, navedena ponavljanja su potencijalno nove satelitne DNA. Međutim, njihova je specifičnost da se gotovo bez iznimke nalaze uklopljeni u transpozone. Detaljna analiza okolnih regija koje omeđuju odabrane nizove uzastopnih ponavljanja pokazala je da sadrže strukturne osobine karakteristične za neautonomne pokretne genetičke elemente Helitron. Postojanje navedenih elemenata istraženo je eksperimentalno i u srodnoj vrsti Ostrea edulis. Utvrđena je uska veza između transpozona nadporodice Helitron i uzastopno ponovljenih sekvenci DNA te su raspravljena dva modela kojim transpozoni šire satelitne nizove. Dobiveni rezultati pokazuju kako pokretni genetički elementi i uzastopno ponovljene sekvence zajedno doprinose složenoj i dinamičnoj organizaciji eukariotskih genoma.

Abstract (english)

Tandem and interspersed repetitive DNA sequences make up a large part of eukaryotic genomes, being present also in bivalve molluscs (class Bivalvia). Recently sequenced genome of Crassostrea gigas shows high abundance of repetitive sequences (36 %). In this work, using bioinformatic approach, 10 most abundant types of tandemly repeated sequences were found. Taking into account monomer lengths typical for satellite DNA and the ability of forming long arrays, these tandem repetas are potentially new satellite DNAs. On the other hand, they are quite special in being inserted into transposons. In fact, a detailed analysis of their flanking regions showed that they bear structural characteristics typical for non – autonomous mobile genetic elements of the Helitron superfamily. The presence of such elements was investigated in the related species Ostrea edulis. A close connection between Helitrons and tandem repeats has been identified and two models for satellite spreading from transposable elements are discussed. The results presented here show that mobile genetic elements and tandem repeats together contribute to a complex and dynamic organization of eukaryotic genomes.

• Keywords: Crassostrea gigas; uzastopna ponavljanja; satelitna DNA; transpozon; Helitron
• Keywords (english): Crassostrea gigas; tandem repeats; satellite DNA; transposable elements; Helitron
• Language: croatian
• URN:NBN: urn:nbn:hr:217:414616
• Study programme: Title: Biology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija (doktor/doktorica znanosti, područje prirodnih znanosti, polje biologija)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Repository: Repository of the Faculty of Science
• Created on: 2017-05-17 11:37:44