Transpozoni i njihova uloga u evoluciji eukariota

undergraduate thesis

• Title (english): Transposons and their role in eukaryotic evolution
• Author: Ena Kolundžić
• Mentor: Ivana Ivančić Baće (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2009, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Iako se to nije uvijek činilo tako, transpozoni tvore važan dio eukariotskog genoma. Prisutni su u genomu eukariota još od njihovog zajedničkog pretka i pronađeni u genomima svih vrsta organizama, no nisu svi bili jednako uspješni u svim organizmima. Očit utjecaj transpozonske aktivnosti na domaćina vidi se u veličini genoma koja varira i između blisko srodnih vrsta, no to nije jedini način na koji su transpozoni utjecali na eukariotske genome i pridonijeli njihovoj evoluciji. Kao insercijski mutagen, transpozon može izazvati promjene koje dovode do djelomičnog ili potpunog gubitka funkcije gena. Izrezivanje transpozona iz genoma je često nepotpuno te može uzrokovati delecije i inverzije u genomu domaćina. U nekim uvjetima ugradnja ili izrezivanje transpozona može dovesti do stvaranja novih alela u genomima, a novi aleli preduvjet su za specijaciju i nastanak novih vrsta. Preraspodjele kromosoma, koje uzrokuju transpozoni, za jedinke koje ih imaju mogu predstavljati selektivnu prednost i dovesti do stvaranja novih funkcionalnih gena ili do raznolikosti vrsta, a postoji teorija da su imali važnu ulogu u evoluciji nekih regulatornih mehanizama eukariota. Svojstva DNA transpozona predodređuju ih za izazivanje mehanizama utišavanja gena u genomu domaćina, a predstavljaju i pokretne mete u genomu za formiranje i održavanje heterokromatina. Jedna od novijih teorija o ulozi transpozona u eukariotskoj evoluciji koristi činjenicu da transpozoni u genomu predstavljaju novu, neiskorištenu DNA koja može služiti za slaganje novih gena iskorištavajući one osobine transpozona koje trebaju genomu domaćina.

Abstract (english)

Transposons make an important part of the eukaryotic genome. They have been present in the genome of the eukaryotic ancestor and have been found in all sorts of organisms, but their success in different eukaryotic genomes has varied. One influence of transposon activity in the host genome manifests in wide differences in genome size observed among eukaryotes, even between closely related species, but that is not the only way in which transposons influenced eukaroytic evolution. Transposons are potent insertional mutagens and can cause changes that lead to partial or complete loss of gene function. Transposon excision is often incomplete and can cause deletions and inversions in the host genome. In some conditions transposon insertions and excisions can lead to generation of new alleles in eukaryotic genomes which are a major force underlying the diversification of species. Choromosomal rearrangements, caused by transposition, can bring a selective advantage to individuals carrying them and lead to the generation of new functional genes or speciation events. DNA transposon properties predispose transposons to elicit gene silencing mechanisms and heterochromatin formation and maintenance. One of the new theories about the role of transposons in eukaryotic evolution is that transposons can be used as a source of raw DNA material for the assembly of new genes and functions, taking advantage of those transposon properties that can be of use to the host genome.

• Keywords: transpozoni; genom eukariota; evolucija eukariota
• Keywords (english): transposons; eukaryotic genome; eukaryotic evolution
• Language: croatian
• URN:NBN: urn:nbn:hr:217:772370
• Study programme: Title: Molecular Biology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) molekularne biologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) molekularne biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2018-03-12 13:53:28