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Effect of polyploidization on species invasive success
Líblová, Zuzana ; Münzbergová, Zuzana (advisor) ; Rooks, Frederick (referee)
Polyploid variants of many species of plants are strikingly frequently found among alien plants on all continents. They also very often have a much larger distribution range of its occurrence, compared to diploid plants in the place of their origin. In many cases, the polyploid cytotype also has increased tolerance to various stress factors or a physiological and morphological characteristics that allow them to survive the conditions in which the diploid plants would have little chance to survive. All this suggests that polyploidy is likely to bring plants an evolutionary advantage over their diploid ancestors, and polyploids therefore can successfully colonize new territories. This thesis summarizes the findings about the possible consequences of polyploidy at different levels in relation to their effects on the properties supporting plant invasive ability. It presents also known hypotheses dealing with possibilities of why plants become invasive after introduction. This is followed by sections devoted to flow cytometry, an important modern method for determining genome size and ploidy level. In conclusion it briefly describes the model species bird vetch (Vicia cracca) and the results of measurements of the degree of ploidy of seeds of this plant from Alaska and Japan.
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Watermilfoils (Myriophyllum) in the central Europe
Hrdinová, Magdalena ; Trávníček, Pavel (advisor) ; Prančl, Jan (referee)
Genus Myriophyllum L. (watermilfoil) belongs to one of the most species-rich genera within Haloragaceae (Saxifragales). It includes three invasive species, which are of major concern - European M. spicatum L., North American M. heterophyllum MICHX. and South American M. aquaticum (VELL.) VERDC. All of them occur in Central Europe as well as native M. verticillatum L. and M. alterniflorum DC. lacking more significant invasive growth up to now. It is not only its invasivness that makes genus Myriophyllum so fascinating. It also displays extremely high phenotypic plasticity which is accompanied by determination difficulties. Moreover, recent research indicates that Myriophyllum tends to hybridize producing more invasive hybrids than parental taxa. Such traits pose a formidable challenge to scientists to deal with possible future invasive growth of non-indigenous Myriophyllum species in Central Europe. Therefore, thorough study of factors influencing evolution success of plants should be conducted. One of the key factors seems to be polyploidy. Research into polyploidy offers a new approach to watermilfoil issues. Additionally, according to preparatory study all native Central European Myriophyllum species can be easily distinguished by flow cytometry. That enables to study polyploidy in an...
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Sources of Sorbus aria agg. variation
Bílá, Jana ; Urfus, Tomáš (advisor) ; Chumová, Zuzana (referee)
Genus Sorbus is a very complex group of vascular plants. Various genetic lineages which can be fixed by apomixis are driven by interspecific hybridisation and polyploidy. Species from S. aria agg. have the highest variation probably due to an extra mechanism - introgressive hybridisation. There are several concepts of the aggregate which are usually based on three main species: S. aria, S. umbellatta and S. graeca. Therefore, new microspecies are derived by genome doubling and hybridisation between the main species. Units of the aggregate are assessed differently as the distinction of taxa is very complicated due to the overlap of the morphological variability. The aggregate itself can be sometimes considered as a category for species of uncertain origin or identification. Four species from S. aria agg. occur in the Czech Republic. In addition, the conclusion offers questions that will be addressed in the master's thesis.
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Microevolutionary processes in the Czech endemic Campanula bohemica
Hanušová, Kateřina ; Suda, Jan (advisor) ; Vít, Petr (referee)
The genus Campanula L. - bellflower - is the largest group of the family Campanulaceae with a subcosmopolitan distribution and poorly resolved infrageneric classification. The evolutionary history of the genus has been shaped by a number of microevolutionary processes, including interspecific hybridization, genome duplication and geographical isolation, that resulted in the genesis of several endemic or geographically restricted species. The centre of endemism in the Czech Republic lies in subalpine altitudes of the Jeseníky and the Krkonoše (Giant) mountains, where three endemic taxa can be found: C. gelida Kovanda, C. rotundifolia L. subsp. sudetica (Hruby) Soó and C. bohemica Hruby. Despite their evolutionary and biogeographical value, there is a lack of information about their phenotypic variation, population structure, evolutionary history and processes acting in their populations. A critical assessment of these topics would require application of modern biosystematics tools. Campanula bohemica is an endangered neoendemics of higher altitudes in the Krkonoše Mts., closely related to C. scheuchzeri Vill., native to the Alps. The endemic species often grows in sympatry with related and morphologically similar C. rotundifolia. The incidence of intermediate morphotypes suggest that both species can...
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Ecological and evolutionary processes in primary contact zone of cytotypes of Knautia arvensis agg.
Hanzl, Martin ; Urfus, Tomáš (referee) ; Kolář, Filip (advisor)
Genome duplication events have played a crucial role in plant evolution. According to recent estimates, nearly all the angiosperms are ancient polyploids. However, establishment of new polyploid lineages within diploid populations seemed to be very unlikely, based on theoretical analyses. Reproductive interactions between the cytotypes (so-called "minority cytotype exclusion") and resource competition might eventually lead to polyploid extinction. On the other hand, the whole variety of factors may compensate both processes under natural conditions (e.g. autogamy, assorative mating, spatial separation of cytotypes). Polyploid establishment in sympatry with diploid progenitor might thus not be as restricted, as previously thought. Subsequent cytotype coexistence may represent a stable equilibrium, or just a transition leading to extinction of one chromosomal race. It is usually almost impossible to discriminate between these alternatives. Polyploid range expansions are usually accompanied by competitive exclusion of diploid cytotype or colonization of new areas and habitats. When two cytological races meet, zones of contact are often formed. Contact zones could be divided into primary and secondary ones. Primary contact zones arise as a consequence of new polyploid emergence within the progenitor's...
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Application for the Data Processing in the Area of Evolutionary Biology
Radakovič, Lukáš ; Burgetová, Ivana (referee) ; Očenášek, Pavel (advisor)
This Bachelor’s thesis describes the design and implementation of the application that has the task to verify the accuracy of the algorithm. Purpose of the algorithm is to analyze mechanisms used in the creation of the phylogenetic tree. The application allows users to specify different parameters of phylogenetic tree, its generation and subsequent analysis using an algorithm. Results of the analysis are written to the output file, giving the user the option of setting file path. Studied algorithm correctly estimates the participation of specific mechanism in the tree formation. Estimates of the absolute and relative share of changes in chromosome number and genome size are less than accurate results.
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Taxonomic study of the Eurasian taxa of Tortula muralis (Pottiaceae, Musci) complex
KOŠNAR, Jiří
The thesis aims at clarifying the taxonomic difficulties in the Tortula muralis complex. For the first time, the group was studied by means of morphometric analysis, ploidy level assessment by flow cytometry, and molecular analysis based on sequencing of ITS region of nuclear ribosomal DNA. Morphometric and cytometric studies found only two well distinguished groups within the complex. These groups corresponded to the markedly variable species T. muralis and to the rather uniform species T. lingulata. Variability in ITS sequences suggested extensive gene flow among some of traditional morphologically defined taxa of the complex. Multiple polytopic autopolyploid origin of polyploids was revealed in some taxa. Changes in taxonomic conception of T. muralis complex were proposed in order to reflect structure of morphological, karyological, and DNA variability in the group. Natural hybridization is probably an important evolutionary mechanism that generated morphological diversity and taxonomic complexity in the mosses of T. muralis complex.
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A cytological, morphometric, and ecological study of \kur{Spergularia echinosperma} in the Czech Republic and its comparison with a closely similar species S. \kur{rubra}
KÚR, Pavel
In the present study, I dealt with morphological, cytological, and ecological research on a rare Central-European species Spergularia echinosperma and its comparison with a similar weedy species S. rubra. Existence of two cytotypes of S. echinosperma significantly differing in their morphology was revealed, as well as distinct morphological differences between the two species were found. Moreover, the analyses revealed one possibly hybridogenous population. In addition, both the species and the cytotypes were also proven to display different germination behavior, which I correlate with their individual ecological adaptations.
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Polyploidy in sturgeons
SRP, Jiří
The aim was to study the theoretical backgrounds of sturgeon fish genetics, focusing on aspects of polyploidy cytogenetics and to learn basics of reproduction and rearing of sturgeon fish in conditions of Central European aquaculture. The work describes an overview of methods for determining ploidy levels in fish, methods of artificial reproduction, methods of fish marking, sampling and evaluation of population samples for cytogenetic analysis. The experimental part dealt with samples of different sturgeon species and their hybrids, and the effects of spontaneous polyploidy and interspecific hybridization on biodiversity conservation of these endangered species were discussed.
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