Uloga ponavljajućih DNA u organizaciji i evoluciji genoma

undergraduate thesis

• Title (english): The role of repetitive DNA in genome structure and evolution
• Author: Lucija Ćužić
• Mentor: Višnja Besendorfer (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2022-09-20, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Prema organizaciji, ponavljajući sljedovi DNA mogu se podijeliti u raspršene
ponavljajuće sljedove DNA ili trasnpozone (retrotranspozone i DNA transpozone) i uzastopne
ponavljajuće sljedove DNA (mikrosatelitne, minisatelitne i satelitne DNA). Segemetne
duplikacije su ponavljajući dijelovi DNA koji mogu biti raspoređeni u rasprešene ili uzastopne
sljedove. Transpozoni su pokretni genetički elementi koji zbog svog mehanizma prenošenja po
genomu uvode velik broj mutacija. Oni izazivaju lokalnu gensku nestabilnost i kromosomske
rearanžmane koji utječu na organizaciju genoma. Mikrosatelitne i minisatelitne DNA su
nestabilni dijelovi genoma koji brzo evoluiraju jer su podložni homolognoj rekombinaciji i
procesu proklizavanja DNA polimeraze. Satelitne DNA karkteristični su sljedovi za
pericentromerna, subtelomerna i intersticijska područjia kromosoma te centromere i telomere
kromosoma. Nekad su se smatrale DNA smećem, ali danas se zna da sudjeluju u organizaciji i
funkciji telomera i cetromera. Neke satelitne DNA transkripcijski su aktivne i imaju ulogu u
ekspresiji gena i regulaciji proteina. Homologni sljedovi u segmentnim duplikacijama mogu
rezultirati ne alelnom homolognom rekombinacijom koja izaziva rearanžmane kromosoma.
Strukturne varijacije koje nastaju kao rezultat segmentnih duplikacija stvaraju nove gene koji
potiču evoluciju. Procesi potaknuti ponavljajućim sljedovima u DNA sudjeluju u evoluciji i
organizaciji genoma u eukariotima, a detaljnije su opisani u ovom radu.

Abstract (english)

When it comes to their organisation, repetitive DNA sequences can be divided into
dispersed repeats or transposons (retrotransposons and DNA transposons) and tandem repeats
(microsatellite, minisatellite and satellite DNA). Segmental duplications are repetitive DNA
sequences with both dispersed and tandem organzation. Due to their transmission mechanism,
transposons introduce large number of mutations in genome. They can cause local gene
instability and chromosomal rearrangements which affect genome organization. Microsatellite
and minisatellite DNAs are unstable parts of eukaryotic genome and they evolve rapidly because
they are places of frequent homologous recombination and DNA polymerase slippage during
DNA replication. Satellite DNAs can be found in the pericentromeric, subtelomeric and
interstitial regions of chromosomes and the centromeres and telomeres of chromosomes. They
were once considered genomic junk, but today we know they have a role in the organization
and function of telomeres and centromeres. Transncriptionally active satellite DNAs play an
important role in gene expression and protein regulation. Homologous sequences in segmental
duplications can result in non-allelic homologous recombination which causes chromosome
rearrangements. Structural variations that occur as a result of segmental duplications create
new genes that initiate evolution. Processes caused by repetitive DNA sequences participate in
the evolution and organization of the genome in eukaryotes, and are described in more detail in
this paper.

• Keywords: transpozoni; satelitne DNA; segmentne duplikacije
• Keywords (english): transposons; satellite DNAs; segmental duplications
• Language: croatian
• URN:NBN: urn:nbn:hr:217:378673
• 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: 2022-10-04 12:37:52