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Evolution of karyotype, sex chromosomes and gene clusters in selected taxa of araneomorph spiders
Voráčková, Diana ; Forman, Martin (advisor) ; Sadílek, David (referee)
Spiders (Araneae) are a diverse group with various sex chromosome systems. The most common is X1X20 sex determination, X1X2 denotes two non-homologous X chromosomes and 0 the absence of Y. The presence of Y chromosome is rare among spiders and has been described mainly in Synspermiata, X1X2Y is probably ancestral constitution for this clade. The family Sicariidae was chosen to elucidate the evolution of sex chromosomes in Synspermiata. Karyotypes of 10 species whose 2n ranged from 19 to 23 were investigated in this study. The most common finding was X1X2Y in all studied Loxosceles species. The derived XY system was discovered in Sicarius. Furthermore, the distributional pattern of molecular cytogenetic markers (genes for 18S rRNA, 5S rRNA, histone H3 and U2 snRNA) was analysed using fluorescence in situ hybridization (FISH). These markers were found exclusively on autosomes, on one or two pairs. FISH with whole-genome probes of both sexes was performed to reveal distribution of Y specific sequences. Various patterns of Y differentiation were found in certain species. Y chromosome was small in all Sicariidae. A larger Y with a pronounced accumulation of Y-specific sequences has been detected in previous works - in the X1X2Y system of a synspermiate Pholcus phalongoides (Pholcidae). Pilot...
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Molecular genetic approaches used in preimplantation genetic analysis of human embryos in assisted reproduction
Limbergová, Jana ; Machoň, Ondřej (advisor) ; Šimoník, Ondřej (referee)
Preimplantation genetic testing is one of the main clinical procedures that take place in assisted reproduction centres around the world. It is sought after by couples for many different reasons. The causes of problems may relate to hereditary diseases that potential parents do not wish to pass on to their offspring, or may include the risk of transmission of chromosomal alterations. In addition, infertility may be caused by an increased risk of embryo aneuploidy, which correlates with mother's increased age and other factors that this bachelor thesis discusses. The bachelor thesis also focuses on up-to-date approaches to cytogenetic examinations for reproductive genetics and discusses recent clinical molecular methods that are used to improve the diagnosis and therapy of infertile couples. These are, for example, microarray methods, quantitative real-time PCR or next-generation sequencing and methods of whole-genome amplification. This work also summarizes methods that are gradually being abandoned, e.g. fluorescent in situ hybridization, and compares their advantages and disadvantages. Key words: preimplantation genetic testing, aneuploidy, structural rearrangements, monogenic diseases, biopsy, fluorescent in situ hybridization, microarray methods, comparative genomic hybridization, quantitative...
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Karyotype analysis of mesothelid spiders
Prokopcová, Lenka ; Král, Jiří (advisor) ; Zrzavá, Magda (referee)
Cytogenetics of mesothelid spiders is largely unkown. The presented diploma thesis is focused on the karyotype evolution of these spiders. As it is the most basal group of spiders, the analysis of its cytogenetics can bring important data about ancestral spider karyotype. In the framework of my thesis, I analysed diploid chromosome numbers, chromosome morphology, meiotic division, sex chromosomes and the pattern of selected molecular markers that were detected by fluorescence in situ hybridization. According to my results, mesothelid spiders have a high number of chromosomes and the prevalence of monoarmed chromosomes. Unlike other spiders, mesothelids have little differentiated sex chromosomes. Key words: evolution, spider, chromosome, karyotype, fluorescence in situ hybridization, nucleolar organiser region, sex chromosomes
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Analysis of sex chromosomes and gene clusters in selected mygalomorph and araneomorph spiders
Pappová, Michaela ; Král, Jiří (advisor) ; Johnson Pokorná, Martina (referee)
1 Abstract: The diploma thesis focuses on study of sex chromosomes evolution and repetitive organized genes of chosen mygalomorph and araneomorph spiders. Spiders are characterized by complexicity of sex chromosome systems, their karyotypes contain multiple sex chromosomes X. Besides multiple X chromosomes they also contain a pair or two pairs of nondiferentiated sex chromosomes X and Y. The used methods include methods of classical cytogenetics (preparation of chromosome slides, C-banding) and methods of molecular cytogenetics (fluorescent in situ hybridization and comparative genome hybridization). Complex sex systems were discovered in the studied Theraphosidae spiders. In Theraphosidae spiders Atropothele socotrana and Poecilotheria vittata neo-sex chromosomes were found. Analysis of molecular differentiation of sex chromosomes suggests low differentiation of Y chromosome in neo-sex chromosomes and pair of nondifferentiated sex chromosomes XY. In haplogyne spider Kukulcania aff. hibernalis (X1X2Y), the Y chromosome was significantly differentiated, male specific signal covered the whole chromosome. Detection of 18S rDNA showed that karyotypes of majority of analysed Theraphosidae spiders and haplogyne spiders contain low number (1 or 2) of nucleolar organizing regions localized terminally, which...
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New insights into the evolution of the W chromosome in Lepidoptera
HEJNÍČKOVÁ, Martina
It is generally accepted that the W chromosome in moths and butterflies (Lepidoptera) has evolved in a common ancestor of Tischeriidae and Ditrysia. Several species of these clades were examined via comparative genomic hybridization to determine the presence of the W chromosome. In addition, in five selected genes their Z-linkage was tested by qPCR. The conserved synteny of the Z chromosome across Tischeriidae and Ditrysia, along with the W chromosome absence in the lower ditrysian families Psychidae and Tineidae, suggests a possible independent origin of the W chromosomes in these two lineages.
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Karyotype analysis of mesothelid spiders
Prokopcová, Lenka ; Král, Jiří (advisor) ; Zrzavá, Magda (referee)
Cytogenetics of mesothelid spiders is largely unkown. The presented diploma thesis is focused on the karyotype evolution of these spiders. As it is the most basal group of spiders, the analysis of its cytogenetics can bring important data about ancestral spider karyotype. In the framework of my thesis, I analysed diploid chromosome numbers, chromosome morphology, meiotic division, sex chromosomes and the pattern of selected molecular markers that were detected by fluorescence in situ hybridization. According to my results, mesothelid spiders have a high number of chromosomes and the prevalence of monoarmed chromosomes. Unlike other spiders, mesothelids have little differentiated sex chromosomes. Key words: evolution, spider, chromosome, karyotype, fluorescence in situ hybridization, nucleolar organiser region, sex chromosomes
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Analýza karyotypu vakonošů (Psychidae, Lepidoptera) metodami klasické a molekulární cytogenetiky
HEJNÍČKOVÁ, Martina
Due to their phylogenetic position, Psychidae play an important role in the investigation of the W chromosome origin in Lepidoptera. Several species of Psychidae were tested for the presence of sex-chromatin and investigated via comparative genomic hybridization. Furthermore, odd chromosome numbers and a Z univalent were observed in females. Overall, this study brings tangible evidence for the absence of the W chromosome in Psychidae, thus contributes to complex knowledge of the W chromosome evolution. In addition, karyotypes of the given species were analyzed using 18S rDNA and histone H3 probes. The results indicate relative stability of their karyotypes.
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Methods of molecular cytogenetics: evolution, analysis, comparison
Budková, Kateřina ; Šolc, Roman (advisor) ; Daňková, Pavlína (referee)
Cytogenetics is a branch of genetics that is concerned with the study of the structure and function of chromosomes, especially during the cell division. Chromosomal abnormalities that may occur during this process are often associated with the emergence of various diseases. Cytogenetic methods are primarily used to detect these abnormalities. Traditional methods allow resolution at the level of whole chromosomes, the introduction of new molecular methods led to a significant refinement of these analyzes. Today's methods allow easy analysis of chromosomes to the level of individual sequences. Despite significant differences between classical and modern cytogenetic techniques, classical cytogenetic methods are not evil, but they are still widely used. Combining classical and molecular methods in order to obtain a comprehensive analysis of chromosomal rearrangements is no exception.
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