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Genome size studies in plants - from intraspecific variation to ecological consequences
Lučanová, Magdalena
Nuclear DNA content (genome size) is one of the basic characteristics of living organisms. In the Angiosperms, the range of genome size is 2,300-fold, which raises questions about the causes and consequences of this tremendous variation. This thesis deals with genome size in plants from the level of intraspecific homoploid variation, through intraspecific ploidy variation, to interspecies comparisons. On various study systems we investigated the dynamics and ranges of genome size variation, tried to reveal possible associations between genome size and selected biological traits, and assessed the extent to which differences in genome size are manifested at the ecological and evolutionary level. As a means of estimating genome size we applied flow cytometry (FCM). In Taraxacum stenocephalum we conducted a detailed study of its enormous genome size variation. We carried out crossings of parents with various genome sizes and compared these parental genome sizes with those of F1 offspring. We also attempted to reveal the association of genome size with various growth traits. In Galium valdepilosum and Arabidopsis arenosa we carried out an extensive flow-cytometric ploidy level screening and compared the distribution and ecological preferences of detected cytotypes. We studied the Andean genus...
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An assessment of interspecific hybridization between Central-European taxa from the genus Nymphaea: insights from flow cytometry and multivariate morphometrics
Kabátová, Klára
Although the genus Nymphaea (waterlily) includes only two native species (N. alba and allopolyploid N. candida) in Central Europe, it poses a great challenge to taxonomy and biosystematics. The determination of both species is hampered by their phenotypic similarities, and species boundaries can be further blurred by interspecific hybridization. In addition, ornamental cultivars of different parentage that often escape (either accidentally or intentionally) from cultivation and can cross with the native ones make the situation even more complex. To get insight into the caryological and phenotypic variability of czech waterlilies, we used DNA flow cytometry and both distance-based and geometric morphometrics. Collections from natural sites showed two different groups of fluorescence intensities, corresponding to N. alba and N. candida, respectively. In addition, intermediate values of nuclear DNA amount were found in some plants from South Bohemia, indicating their hybrid origin. Morphologically, these plants were partly intermediate between the native species, partly having their separate tendency to oversized growth. Surprisingly, ornamental cultivars (obtained either from commercial stocks or as escapes from the field) possessed the smallest genome sizes. The amount of nuclear DNA therefore seems...
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Evolution of ascospore morphology and their dispersal in bryophilous Pezizales
Janošík, Lukáš ; Koukol, Ondřej (advisor) ; Trávníček, Pavel (referee)
Bryophilous Pezizales represent a species-rich group of fungi closely associated with bryophytes. Their ascospore morphology is highly variable and they strongly differ also in the genome size and ecology. They could thus represent an interesting model system for the research of evolution of ascospore morphology and their dispersal. The aims of my thesis were to test whether their genome size, number of nuclei in ascospores and ecology of host bryophyte influence their ascospore morphology and to experimentally test the effect of ascospore morphology on their active dispersal. I studied 52 species of bryophilous Pezizales. I reconstructed their phylogeny based on the sequences of three DNA regions, which I then used for the testing of relationships between individual variables using the phylogenetic generalized least squares. For the majority of species, I obtained measurements from morphometric analysis, genome size measurements using flow cytometry, and determined the number of nuclei in their ascospores using the fluorescent microscopy. I localised the infection apparatus and included also the ecological characteristics of the host bryophytes into the analyses. Using the experiments with horizontal ascospore discharge, I measured the distance of active ascospore ejection and recorded whether...
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Genome size in the evolution of cockroaches
Stuchlíková, Magdalena ; Janšta, Petr (advisor) ; Vít, Petr (referee)
Genome size or nuclear DNA content is a a trait which varies greatly among living organisms, with no apparent relashionship between genome size and organismal complexity. It is usually described using the C-value as either a number of base pairs or picograms of DNA. Unresolved questions regarding mechanisms influencing genome size and relationships between genome size and other organismal traits are together known as the C-value enigma. Genome size is known to positively correlate with cell size and negatively with developmental and cell division rate. A maximum constraint of 2 pg has also been proposed for haploid genome sizes of holometabolous insects. Despite the fact that there are about one million described insect species, genome sizes are only known in a fraction of them. This thesis thus aims to extend the dataset of known insect genome sizes by as many species of cockroaches (Blattodea) as possible. Another aim is to compare results with known phylogeny and also to compare difference in genome size between sexes. Flow cytometry was used for genome size estimations, which is a rapid, simple and effective method, also suitable for study of ploidy levels and other cellular charasteristics.
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Influence of sampling and fixation on measuring of genome size
Halačka, Karel ; Vetešník, Lukáš ; Fedorčák, J. ; Koščo, J.
Assessment of genome size is an important aspect of many modern studies on fish. Blood is the most common DNA source in fish studies due to its relative ease of sampling and processing. Fish blood, however, precipitates rapidly, leading to clotting. Consequently, anticoagulants (primarily heparin) are added at the time of sampling. Using of increasing heparin concentrations resulted in notable increases in fish erythrocyte genome size readings compared to a non-heparinised control. The differences observed were highly significant, suggesting that the results of previous comparative studies or those determining individual polyploidy may need reinterpretation.
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Genome size estimation in protists
Lukeš, Jiří ; Čertnerová, Dora (advisor) ; Veselská, Tereza (referee)
This bachelor's thesis presents the current knowledge of the size of the genome in protists with a focus on the description and comparison of individual methods that were used to solve this issue. Genome size is a characteristic trait of all living organisms and other physiological features related to genome size are also mentioned. Of the selected methods, the greatest emphasis is placed on the flow cytometry, which is considered reliable and currently provides the most data on the size of protist genomes. In addition to flow cytometry, the contribution of whole genome sequencing to understanding the size of protist genomes is mentioned. Problems with estimating the size of protist genomes results from the heterogeneity of protists as a study group and from the non-uniform procedures within individual methods, which make possible comparisons difficult. Protists are evaluated in the work as an insufficiently studied group, within which the size of the genome varies by approximately 200,000×. The conclusion of the thesis summarizes the current knowledge about the genome size of relatively studied groups of protists. Key Words: Genome size, C-value, Protists, Flow cytometry, whole-genome sequencing, pulsed field gel electrophoresis, Feulgen densitometry, microspectrophotometry
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Genome size studies in plants - from intraspecific variation to ecological consequences
Lučanová, Magdalena
Nuclear DNA content (genome size) is one of the basic characteristics of living organisms. In the Angiosperms, the range of genome size is 2,300-fold, which raises questions about the causes and consequences of this tremendous variation. This thesis deals with genome size in plants from the level of intraspecific homoploid variation, through intraspecific ploidy variation, to interspecies comparisons. On various study systems we investigated the dynamics and ranges of genome size variation, tried to reveal possible associations between genome size and selected biological traits, and assessed the extent to which differences in genome size are manifested at the ecological and evolutionary level. As a means of estimating genome size we applied flow cytometry (FCM). In Taraxacum stenocephalum we conducted a detailed study of its enormous genome size variation. We carried out crossings of parents with various genome sizes and compared these parental genome sizes with those of F1 offspring. We also attempted to reveal the association of genome size with various growth traits. In Galium valdepilosum and Arabidopsis arenosa we carried out an extensive flow-cytometric ploidy level screening and compared the distribution and ecological preferences of detected cytotypes. We studied the Andean genus...
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Genome size studies in plants - from intraspecific variation to ecological consequences
Lučanová, Magdalena ; Trávníček, Pavel (advisor) ; Leitch, Ilia (referee) ; Šmarda, Petr (referee)
Nuclear DNA content (genome size) is one of the basic characteristics of living organisms. In the Angiosperms, the range of genome size is 2,300-fold, which raises questions about the causes and consequences of this tremendous variation. This thesis deals with genome size in plants from the level of intraspecific homoploid variation, through intraspecific ploidy variation, to interspecies comparisons. On various study systems we investigated the dynamics and ranges of genome size variation, tried to reveal possible associations between genome size and selected biological traits, and assessed the extent to which differences in genome size are manifested at the ecological and evolutionary level. As a means of estimating genome size we applied flow cytometry (FCM). In Taraxacum stenocephalum we conducted a detailed study of its enormous genome size variation. We carried out crossings of parents with various genome sizes and compared these parental genome sizes with those of F1 offspring. We also attempted to reveal the association of genome size with various growth traits. In Galium valdepilosum and Arabidopsis arenosa we carried out an extensive flow-cytometric ploidy level screening and compared the distribution and ecological preferences of detected cytotypes. We studied the Andean genus...
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Lichen ecology in the relationship to functional diversity and genome size
Konečná, Eliška ; Malíček, Jiří (advisor) ; Palice, Zdeněk (referee)
Eliška Konečná Lichen ecology in the relationship to functional diversity and genome size Abstract This bachelor thesis in its first part summarises and characterizes lichen functional traits and sums up known relation between particular traits and ecological factors of the enviroment. Second part of the thesis focuses on question of genome measurment in general and than summarises known information about lichen genom size. In the second part there is partial focus on relation between genom size and ekology of organisms as well, which could become focus of some study in the future. Key words: functional traits, lichens, mycobiont, genome size
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Orchids as a model for research in ecophysiological adaptations of mycoheterotropic plants
Ponert, Jan ; Lipavská, Helena (advisor) ; Gryndler, Milan (referee) ; Chrtek, Jindřich (referee)
Perhaps all orchids are mycotrophic at early developmental stages, while majority of species photosynthesize at adulthood and only about 200 species remain fully mycotrophic for the whole life. Mycotrophy affects orchids at many levels. In this thesis, I focus on four aspects of orchid biology, which could be connected with mycotrophy: (i) systematics, (ii) genome size and endoreduplication, (iii) regulation of seed germination and (iv) mechanism of transfer of carbon and energy from fungi to orchids. There are over 27,000 recently recognized orchid species, nevertheless new ones are still discovering and old ones are revisiting. In this work I present a description of new species, Cleisostoma yersinii, and its morphological, anatomical, ecological and systematic characterization. Phylogeny reconstruction confirmed relationship with C. birmanicum. In the subtribe Podochileae, I reappraised the genus Campanulorchis to establish monophyletic but also morphologically defined group. For both abovementioned genera I prepared the artificial identification key. In the genus Dactylorhiza I revised taxa present in our country and I prepared an identification key which firstly mentions D. maculata subsp. elodes from Czech Republic. Orchid species diversity is probably reflected in genome structure. Results...
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