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dc.contributor.author
Fouché, Simone
dc.contributor.supervisor
McDonald, Bruce A
dc.contributor.supervisor
Croll, Daniel
dc.contributor.supervisor
Suh, Alexander
dc.date.accessioned
2020-07-13T05:58:04Z
dc.date.available
2020-07-12T18:10:15Z
dc.date.available
2020-07-13T05:58:04Z
dc.date.issued
2020
dc.identifier.uri
http://hdl.handle.net/20.500.11850/425971
dc.identifier.doi
10.3929/ethz-b-000425971
dc.description.abstract
Chromosome rearrangements involve duplication, deletions, inversions and translocations. Breakpoints of chromosome rearrangements are frequently in close proximity to transposable elements (TEs). TEs are known to mediate chromosome rearrangements through their own activity or through ectopic recombination. During this PhD we aimed to better understand the causes and consequences of chromosome rearrangements in Zymoseptoria tritici, an important pathogen of wheat. To study the origins of chromosome rearrangements the first chapter focusses on the de-repression of TEs, which is stress induced during a wheat infection cycle as well as in nutrient limited media. Stress was shown to drive epigenetic changes and trigger TE de-repression in multiple organisms. We find that TEs respond differently to stresses. Furthermore, effector genes in close proximity to TEs show a de-repression during early infection suggesting that TEs and effectors may be under the same epigenetic control. De-repressed TEs can place a mutational burden on the genome. Therefore, in the second chapter we aimed to quantify the number of chromosome rearrangements occurring in all 21 chromosomes in hundreds of progeny through a single round of meiosis. We find that the fidelity with which chromosomes go through meiosis differs between chromosomes. Chromosomes with a higher repeat content and lower synteny were less stable. In the final chapter we focused on a single rearranged chromosome that was generated by a self-fusion. We hypothesized that such a fused chromosome would go through degenerative breakage-fusion-bridge (BFB) cycles. Here we show the exact process whereby the highly unstable fused chromosome was created through ectopic recombination between a specific repeat family. We trace the fate of the novel chromosome through five rounds of meiosis and show that degenerative cycles occur through repeated ectopic recombination and non-disjunction. The ability of Z. tritici to tolerate chromosome duplications, losses and rearrangements makes this species a great model to observe and investigate the interplay between TE dynamics and chromosome rearrangements.
en_US
dc.format
application/pdf
en_US
dc.language.iso
en
en_US
dc.publisher
ETH Zurich
en_US
dc.rights.uri
http://rightsstatements.org/page/InC-NC/1.0/
dc.title
Drivers of genome evolution in a fungal pathogen of wheat
en_US
dc.type
Doctoral Thesis
dc.rights.license
In Copyright - Non-Commercial Use Permitted
dc.date.published
2020-07-13
ethz.size
290 p.
en_US
ethz.code.ddc
DDC - DDC::5 - Science::570 - Life sciences
en_US
ethz.identifier.diss
26555
en_US
ethz.publication.place
Zurich
en_US
ethz.publication.status
published
en_US
ethz.leitzahl
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02350 - Dep. Umweltsystemwissenschaften / Dep. of Environmental Systems Science::02720 - Institut für Integrative Biologie / Institute of Integrative Biology::03516 - McDonald, Bruce / McDonald, Bruce
en_US
ethz.leitzahl.certified
ETH Zürich::00002 - ETH Zürich::00012 - Lehre und Forschung::00007 - Departemente::02350 - Dep. Umweltsystemwissenschaften / Dep. of Environmental Systems Science::02720 - Institut für Integrative Biologie / Institute of Integrative Biology::03516 - McDonald, Bruce / McDonald, Bruce
en_US
ethz.date.deposited
2020-07-12T18:10:29Z
ethz.source
FORM
ethz.eth
yes
en_US
ethz.availability
Open access
en_US
ethz.rosetta.installDate
2020-07-13T05:58:16Z
ethz.rosetta.lastUpdated
2021-02-15T15:25:25Z
ethz.rosetta.versionExported
true
ethz.COinS
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