Evolucija retroelemenata

undergraduate thesis

• Title (english): The evolution of retroelements
• Author: Stella Patajac
• Mentor: Damjan Franjević (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2023-09-19, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Retroelementi su pokretne DNA sekvence s vrlo velikom zastupljenošću u eukariotskim
genomima, koje obuhvaćaju retrotranspozone i retroviruse. Sve skupine retroelemenata uvelike se
razlikuju u svojoj strukturi, no velikoj većini zajednička je RT domena koja kodira reverznu
transkriptazu, enzim uključen u njihovu transpoziciju. Aminokiselinske sekvence reverzne
transkriptaze i nukleotidne sekvence RT domene glavni su odabir pri provođenju filogenetičkih
analiza retroelemenata, no zbog velike učestalosti horizontalnog transfera i drugih čimbenika koji
utječu na njihovu evoluciju, ove su analize otežane. Dodatnu podržanost mogu pružiti filogenetičke
analize temeljene na drugim domenama zajedničkima pojedinim skupinama. Na taj način utvrđeni
su filogenetički odnosi svih skupina retroelemenata, zajedno s određenim skupinama virusa i nekim
eukariotskim, ali i bakterijskim enzimima te je razjašnjeno podrijetlo retrovirusa. Retroelementi
integrirani u genomima podliježu djelovanju prirodne selekcije, a ovisno o svom učinku na
vijabilnost i reproduktivni uspjeh domaćina, mogu se izgubiti ili fiksirati u populaciji, utječući tako
na evoluciju genoma svojih domaćina.

Abstract (english)

Retroelements are mobile DNA sequences very abundant in eukaryotic genomes, that include
retrotransposons and retroviruses. All groups of retroelements differ greatly in their structure, but
one thing the vast majority of them have in common is their RT domain which encodes reverse
transcriptase, an enzyme involved in their transposition. Reverse transcriptase amino acid
sequences and RT domain nucleotide sequences represent the main choice in conducting
phylogenetic analyses of retroelements, but due to their high frequency of horizontal transfer and
other factors affecting their evolution, these analyses are made difficult. Additional support can be
provided by phylogenetic analyses based upon other domains that are common to some individual
groups. In this regard, the phylogenetic relations of all groups of retroelements, together with
certain groups of viruses and some eukaryotic and even bacterial enzymes, were determined, and
the origin of retroviruses clarified. Retroelements integrated into genomes are subject to natural
selection, and depending on their effect on their host’s viability and reproductive success, they can
be lost or fixed in the population, thus affecting the evolution of their host’s genome.

• Keywords: retrotranspozoni; retrovirusi; endogeni retrovirusi; reverzna transkriptaza; LTR
• Keywords (english): retrotransposons; retroviruses; endogenous retroviruses; reverse transcriptase; LTR
• Language: croatian
• URN:NBN: urn:nbn:hr:217:053396
• 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: 2023-09-20 12:37:42