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Robertsonian translocations and their involvement into genome evolution
Mlnáříková, Barbora ; Forman, Martin (advisor) ; Sember, Alexandr (referee)
Chromosome aberrations play an important role in human pathologenesis as well as in evolution of many organisms. Robertsonian translocation or centric fusion are the most frequent chromosomal rearrangements in mammals. The most investigated model for their research is house mouse Mus musculus. The standard karyotype of a mouse consists from 40 acrocentric chromosomes, notably there are more than one hundred wild populations that are characterized by various combination of metacentrics, formed by centric fusion of different acrocentrics. Several models have been proposed for the formation of metacentrics, taking account of the sequential structure of their centromeres and short arms in mouse. Segregation distortion in favor of metacentrics is present in female and/or male meiosis, such as meiotic drive can positively affect the degree of fixation of metacentric chromosomes in certain population. Centric fusions have been also presented in evolution of other organisms. Cytogenetic data in spiders indicate the possibility of similar phenomena in the most diversified group of spiders, Entelegynae. Spiders are notable for their unusual sex chromosome systems. Centric fusions also play an important role in the evolution of sex chromosomes and the formation of neo-sex chromosome systems. So far, there is...
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Genomics and cell biology of oxymonads
Treitli, Sebastian Cristian ; Hampl, Vladimír (advisor) ; Brune, Andreas (referee) ; Beneš, Vladimír (referee)
Oxymonads are a group of poorly studied protists living as intestinal endosymbionts in the gut of insects and vertebrates. In this thesis I focused on the study of phylogeny, genomics and cell biology of oxymonads. Using culture-based approaches, we uncovered the hidden diversity of small oxymonads and described one new genus and six new species. In Monocercomonoides exilis, the only oxymonad with a published genome, we investigated the genome organization using fluorescence in situ hybdridization (FISH) against the telomeric regions and single-copy genes. Our results show that the genome is most probably haploid being organized in 6-7 chromosomes. Annotation of the genome revealed that the DNA replication and repair mechanisms in M. exilis are canonical and they seem more complete than those of other metamonads whose genomes are available. Although M. exilis lacks in any traces of mitochondria, its genome annotation revealed that other cellular systems do not markedly differ from other eukaryotes. Our taxon-rich phylogenetic analyses suggested that the genus Monocercomonoides is closely related to the oxymonad Streblomastix strix, which is found exclusively in the gut of the termites. Streblomastix strix, as opposed to M. exilis, is highly adapted to harbour bacterial ectosymbionts. Since S. strix...
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Genomics of Preaxostyla flagellates
Novák, Lukáš ; Hampl, Vladimír (advisor) ; Hirt, Robert (referee) ; Van der Giezen, Mark (referee)
Protists inhabiting oxygen-depleted environments have evolved various adaptation to thrive in their niches, including modified mitochondria to various degrees adapted to anaerobiosis. The most radically altered forms of these organelles (Mitochondria-Related Organelles, MROs) have completely lost their genomes and other defining features of canonical aerobic mitochondria. Anaerobic protists are often found as endobionts (parasites, mutualists, etc.) of larger organisms. The endobiotic lifestyle combined with anaerobiosis poses another source of evolutionary pressure forcing unique adaptations in the endobionts. Here we present new insights into the adaptations of an anaerobic protistan phylum Preaxostyla, especially with regard to the reductive evolution of mitochondria, which, uniquely among all known eukaryotes, led to a complete loss of the organelle in the oxymonad Monocercomonoides exilis. We have obtained M. exilis genomic assembly of good quality and completeness, as well as genomic and transcriptomic data of varying quality and completeness from 9 other Preaxostyla species. Based on extensive, thorough gene searches and functional gene annotation on these datasets, as well as phylogenetic analyses and protein localization experiments, we conclude: 1) M. exilis has completely lost the...
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Evolution of euglenid plastid proteome
Novák Vanclová, Anna ; Hampl, Vladimír (advisor) ; Gruber, Ansgar (referee) ; Maier, Uwe (referee)
Endosymbiotic gain and transfer of plastids is a widespread evolutionary phenomenon and a major driving force of eukaryotic evolution. The integration of a new organelle is accompanied by changes in its structure, gene content, molecular mechanisms for biogenesis and transport, and re-wiring of the host and organelle metabolic pathways. To understand the course and underlying mechanisms of plastid evolution, it is important to study these processes in variety of secondary algae and notice their differences and similarities. Euglenophytes gained their plastids from green eukaryotic algae after a long history of heterotrophic lifestyle. In my thesis, I participated in analyses of newly generated sequence datasets: transcriptomes of Euglena gracilis and Euglena longa and mass spectrometry-determined proteome of E. gracilis plastid with especial regard to the potential novelties associated with plastid gain and incorporation. In the resulting publications we particularly focus on plastid protein import machinery and targeting signals and report extremely reduced TIC and completely absent TOC in euglenophyte plastid. Using the proteomic dataset, we predict potential novel plastid protein translocases recruited from ER/Golgi and re-analyze plastid signal domains, characterizing previously overlooked...
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Bacterial species delineation based on parameters derived from numerical representations of genome
Oweis, Kamil ; Jugas, Robin (referee) ; Maděránková, Denisa (advisor)
Modern methods of processing genomic data yield good results, however they are often redeemed by time consummation. This is mainly the reason why this thesis deals with numerical methods of bacterial genome processing which could be a suitable alternative for current methods, both in terms of quality and computational demands. This thesis presents the current methods used for processing of genomes in silico and proposes suitable numerical presentations for the whole genome analysis. Some of these methods are programmed and used for processing further in this diploma thesis. In it, various mathematical and statistical methods are being tested, ones that could lead to successful species delineation of bacteria by numerical presentations of their genomes.
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Gene order conservation in bacterial genomes
Martinková, Tereza ; Sedlář, Karel (referee) ; Maděránková, Denisa (advisor)
Theoretical part of the thesis deals with basic concepts such as bacterial genome, comparative genomics and mainly synteny blocks. Here is explained what synteny is and what is its importance. In the theoretical part, the GenBank format is also mentioned, its content and usage. The practical part is focused on searching similarities in DNA sequences of reference bacteria with selected bacteria, their sorting by means of greedy algorithm and visualization of similarities using phylogenetic tree.
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Avian polyomaviruses
Škvára, Petr ; Fraiberk, Martin (advisor) ; Forman, Martin (referee)
Avian polyomaviruses are small, nonenveloped viruses from family Polyomaviridae, which can cause acute infection with high mortality of infected birds. In contrast with other polyomaviruses, avian polyomaviruses do not share similar pathogenesis, because most of them do not cause acute diseases. The main point of this work is to summarize available information about avian polyomaviruses and to compare them to each other. This work also compares avian polyomaviruses with mammalian polyomaviruses. The primary focus is made on genome organization, structure and function of viral proteins, but also on pathogenesis and epidemiology of avian polyomaviruses. In conclusion, even if avian polyomaviruses share common signs with other polyomaviruses, they have different conserved sequences, host specificity and pathogenicity. Summary of current knowledge about avian polyomaviruses could help to understand the importance of this newly established genus in the field of polyomavirus research. Key words: avian polyomaviruses, taxonomy, genome, viral proteins, pathogenesis
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Gene order conservation in bacterial genomes
Martinková, Tereza ; Sedlář, Karel (referee) ; Maděránková, Denisa (advisor)
Theoretical part of the thesis deals with basic concepts such as bacterial genome, comparative genomics and mainly synteny blocks. Here is explained what synteny is and what is its importance. In the theoretical part, the GenBank format is also mentioned, its content and usage. The practical part is focused on searching similarities in DNA sequences of reference bacteria with selected bacteria, their sorting by means of greedy algorithm and visualization of similarities using phylogenetic tree.
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Evoluce genomu bakteriálních symbiontů vši \kur{Polyplax serrata} (Phthiraptera, Anoplura)
ŘÍHOVÁ, Jana
Blood-sucking louse Polyplax serrata harbor two phylogenetically distinct symbiotic bacteria from the orders Legionellales (Gammaproteobacteria) and Neisseriales (Betaproteobacteria). Based on rigorous phylogenetic analyses, the first bacteria was confirmed as member of genus Legionella, and the name Candidatus Legionella polyplacis, sp. n. was proposed. Vertical transgeneration transmission was proved by visualisation of the symbiont in host tissues. Improved genome of latter symbiont is considerably larger and possesses more metabolic functions. In the genome, I found horizontally transferred operon, which encode synthesis of enzymes involved in urea cleavage.
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