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Detection of repetitive sequences in genomes
Puterová, Janka ; Jedlička, Pavel (oponent) ; Kléma, Jiří (oponent) ; Zendulka, Jaroslav (vedoucí práce)
Repetitive sequences can make up a significant part of the genome, in some cases more than 80%, but scientists have often overlooked them. Today we know that repeats have various functions in the genomes and are divided into two main groups: interspersed and tandem repeats. This work aimed to develop bioinformatics tools to detect repetitive sequences, either directly from sequencing data generated by sequencers or assembled genomes. In the introductory part, the work provides an insight into the issue and an overview of the repeat types occurring in genomes. Furthermore, the work deals with existing approaches and tools with an aim to detect repeats directly from the assembled sequences. The main contribution to this area was developing the digIS tool, which aims to detect insertion sequences that represent the most abundant interspersed repeats in prokaryotes. digIS is based on the principle of profile hidden Markov models constructed for the catalytic domains of transposases, representing the most conserved part of the insertion sequences and retaining a secondary structure within the family. Subsequently, the work provides an overview of sequencing technologies and discusses existing methods for detecting repeats directly from sequencing data without the need for prior genome assembly. A novel approach for a detailed analysis of tandem repeats is presented. This approach extends the primary analysis of RepeatExplorer, which detects and characterizes repeats directly from sequencing data. The work further discusses the applications of repeat detection in biological research, especially from the point of view of comparative repeatome studies and the evolution of sex chromosomes. Finally, the work summarizes the research results in the form of four articles published in international journals, the full text of which is available in the appendices, and provides a general summary of the work together with possibilities for future research.
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Bioinformatický nástroj pro anotaci transposonů
Jenčo, Michal ; Martínek, Tomáš (oponent) ; Puterová, Janka (vedoucí práce)
Táto práca poskytuje teoretické východiská pre návrh nového bioinformatického nástroja pre anotáciu transpozónov so zameraním na ich prídavné štruktúrne prvky. Sú v nej z biologického hľadiska popísané transpozóny, mobilné elementy v DNA, ich rozdelenie a vnútorná štruktúra. Ďalej sa zaoberá prehľadom a rozdelením dostupných bioinformatických nástrojov na identifikáciu a anotáciu transpozónov, popisom funkcie a implementácie vybraných z nich. Následne je popísaný návrh a implementácia nového bioinformatického nástroja na vyhľadávanie a anotáciu LTR retrotranspozónov so zameraním na extra ORF a tandemové repetície. Funkcionalita nástroja bola testovaná na genóme A. thaliana. Bolo identifikovaných 95 skupín konzervovaných extra ORF a 10 skupín konzervovaných tandemových repetícií.
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Rekonstrukce repetitivních elementů DNA
Hypský, Jan ; Martínek, Tomáš (oponent) ; Puterová, Janka (vedoucí práce)
Eukaryotické genomy obsahují velké množství repetitivních struktur. Jejich detekce a sestavení patří dnes k hlavním výzvám bioinformatiky. Tato práce obsahuje hlavní klasifikaci repetitivní DNA a představuje implementaci nového de novo assembleru, zaměřeného na hledání a sestavení LTR retrotranspozonů a satelitní DNA. Assembler přijímá na svém vstupu krátké ready (single nebo pair-end), získané sekvenátory druhé generace (NGS). Tento assembler je založen na přístupu Overlap Layout Consensus.
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Evolutionary dynamics of satellite DNA in plant genomes
ÁVILA ROBLEDILLO, Laura
Satellite DNA (satDNA) belongs to the highly repetitive fraction of eukaryotic genomes. It is best characterized by the formation of long arrays of almost identical sequences that are tandemly repeated. These repeats are widely distributed in plant species where they can make up a substantial proportion of their genomes. Despite the long history of satDNA research, the classic methodology did not allow for its comprehensive characterization. Consequently, the fragmentary information gathered during the last 60 years does not answer the many questions surrounding the evolution of these elements. The development of new techniques in sequencing, together with the availability of new bioinformatics tools for analyzing different genome fractions, has presented an opportunity to advance studies of tandem repeats. This thesis describes the landscape characterization of satDNA in the genome of Fabeae species by exploring the diversity of satDNA within a genome, the association of these elements with functional centromeres, as well as their genome-wide organization. We employed new computational pipelines specifically designed for the analysis of tandem repeats from next generation sequencing data, and combined their results with molecular and cytogenetic methods to achieve comprehensive characterization of the satellite repeats.
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Detection of repetitive sequences in genomes
Puterová, Janka ; Jedlička, Pavel (oponent) ; Kléma, Jiří (oponent) ; Zendulka, Jaroslav (vedoucí práce)
Repetitive sequences can make up a significant part of the genome, in some cases more than 80%, but scientists have often overlooked them. Today we know that repeats have various functions in the genomes and are divided into two main groups: interspersed and tandem repeats. This work aimed to develop bioinformatics tools to detect repetitive sequences, either directly from sequencing data generated by sequencers or assembled genomes. In the introductory part, the work provides an insight into the issue and an overview of the repeat types occurring in genomes. Furthermore, the work deals with existing approaches and tools with an aim to detect repeats directly from the assembled sequences. The main contribution to this area was developing the digIS tool, which aims to detect insertion sequences that represent the most abundant interspersed repeats in prokaryotes. digIS is based on the principle of profile hidden Markov models constructed for the catalytic domains of transposases, representing the most conserved part of the insertion sequences and retaining a secondary structure within the family. Subsequently, the work provides an overview of sequencing technologies and discusses existing methods for detecting repeats directly from sequencing data without the need for prior genome assembly. A novel approach for a detailed analysis of tandem repeats is presented. This approach extends the primary analysis of RepeatExplorer, which detects and characterizes repeats directly from sequencing data. The work further discusses the applications of repeat detection in biological research, especially from the point of view of comparative repeatome studies and the evolution of sex chromosomes. Finally, the work summarizes the research results in the form of four articles published in international journals, the full text of which is available in the appendices, and provides a general summary of the work together with possibilities for future research.
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CpSAT-1, a transcribed satellite sequence from the codling moth,\kur{Cydia pomonella\kur{}}
DALÍKOVÁ, Martina
Satellite DNA represents one of the major components of repetitive genome components. Recent research is bringing more and more evidence about importance of this type of DNA, which can play both structural and functional roles in eukaryotic genomes. In this study, we described newly discovered satellite DNA in Cydia pomonella, CpSAT-1. Although this satDNA can be found in all chromosomes, it is surprisingly underrepresented on the W chromosome, the only heterochromatin block in Cydia pomonella genome. The CpSAT-1 is transcribed in all tested developmental stages and tissues. However, the potentially functional motives were found predominantly in non-conserved parts of monomer sequence. Thus the function of this new satellite DNA remains unknown.
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Rekonstrukce repetitivních elementů DNA
Hypský, Jan ; Martínek, Tomáš (oponent) ; Puterová, Janka (vedoucí práce)
Eukaryotické genomy obsahují velké množství repetitivních struktur. Jejich detekce a sestavení patří dnes k hlavním výzvám bioinformatiky. Tato práce obsahuje hlavní klasifikaci repetitivní DNA a představuje implementaci nového de novo assembleru, zaměřeného na hledání a sestavení LTR retrotranspozonů a satelitní DNA. Assembler přijímá na svém vstupu krátké ready (single nebo pair-end), získané sekvenátory druhé generace (NGS). Tento assembler je založen na přístupu Overlap Layout Consensus.
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Bioinformatický nástroj pro anotaci transposonů
Jenčo, Michal ; Martínek, Tomáš (oponent) ; Puterová, Janka (vedoucí práce)
Táto práca poskytuje teoretické východiská pre návrh nového bioinformatického nástroja pre anotáciu transpozónov so zameraním na ich prídavné štruktúrne prvky. Sú v nej z biologického hľadiska popísané transpozóny, mobilné elementy v DNA, ich rozdelenie a vnútorná štruktúra. Ďalej sa zaoberá prehľadom a rozdelením dostupných bioinformatických nástrojov na identifikáciu a anotáciu transpozónov, popisom funkcie a implementácie vybraných z nich. Následne je popísaný návrh a implementácia nového bioinformatického nástroja na vyhľadávanie a anotáciu LTR retrotranspozónov so zameraním na extra ORF a tandemové repetície. Funkcionalita nástroja bola testovaná na genóme A. thaliana. Bolo identifikovaných 95 skupín konzervovaných extra ORF a 10 skupín konzervovaných tandemových repetícií.
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Mechanisms of molecular differentiation of sex chromosomes in Lepidoptera and their evolution
DALÍKOVÁ, Martina
Sex chromosomes represent a unique part of the genome in many eukaryotic organisms. They differ significantly from autosomes by their evolution, specific features, and meiotic behaviour. Recent advances in the knowledge of sex chromosomes in non-model organisms have been largely enabled by modern cytogenetic methods. The present study explores several topics related to sex chromosomes in Lepidoptera, the largest group of animals with female heterogamety, using methods of molecular cytogenetics, immunocytogenetics, and molecular biology. These topics include physical mapping of chromosomes by BAC-FISH, molecular differentiation and composition of the W chromosome, differences in the evolution of the W and Z chromosome, and meiotic sex chromosome inactivation. The results obtained brought new information not only about the W and Z chromosomes in Lepidoptera, but also about the evolution and specific features of sex chromosomes in general.
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