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Microevolutionary processes in mixed-ploidy populations of plants
Čertner, Martin ; Kolář, Filip (advisor) ; Ramsey, Justin (referee) ; Duchoslav, Martin (referee)
Polyploidization (whole-genome duplication) is widely considered one of the most important evolutionary forces driving the diversification of flowering plants. Polyploids tend to originate recurrently and many plant species retain individuals of two or more different ploidy levels in certain parts of their distributional range of even within their populations. The main aim of this thesis was to address the understudied aspects of polyploid speciation by employing new, convenient methods and/or studying plant model systems with unique features. Difference in monoploid genome size of Tripleurospermum inodorum (Asteraceae) cytotypes provided a unique opportunity for addressing the rate of spontaneous polyploidization in natural populations by enabling the easy distinction of neopolyploid mutants from long-established polyploids in routine flow-cytometric analyses. Repeated ploidy screening in mixed-ploidy populations of annual T. inodorum have been, to our knowledge, the very first attempt to document temporal changes in cytotype composition in situ. In spite of considerable between- year oscillations in cytotype frequencies, both diploids and tetraploids usually persisted locally for several consecutive years. The common incidence of such ploidy mixtures along with a partial fertility of triploid...
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Mechanisms driving di- and tetraploid coexistence in mixed-ploidy populations of Tripleurospermum inodorum
Nedomová, Anežka ; Čertner, Martin (advisor) ; Dostálek, Tomáš (referee)
Genome duplication plays a significant role in plant evolution. Formation of new polyploids is generally considered to be rare. Nevertheless, under natural conditions mixed-ploidy populations occur in relatively large numbers. Only the observations in the cytotype contact zone can identify all the factors affecting the stability or instability of the population. Number of research focusing on study of cytotype coexistence in natural mixed-ploidy populations is still low. As a model system for the study of mechanisms governing cytotype coexistence was chosen the Tripleurospermum inodorum. Research focused on natural mixed-ploidy populations and also on planted mixed-ploidy populations. Permanent plots were located in south, west, northwest and north Bohemia. Field observations were supplemented by cultivation experiments carried out in the greenhouse. Several phenomena were discovered at the level of whole populations. Cytotype distribution in the plot was random. The spatial structure of natural populations was quickly changing even within a single season. Even between single plot evaluations the cytotype ratios varied. Three percent of all plants were triploid hybrids. Most often detected cytotype in soil seed bank was diploid cytotype. The study of population dynamics shows, that tetraploids are...
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Microevolutionary processes in mixed-ploidy populations of plants
Čertner, Martin
Polyploidization (whole-genome duplication) is widely considered one of the most important evolutionary forces driving the diversification of flowering plants. Polyploids tend to originate recurrently and many plant species retain individuals of two or more different ploidy levels in certain parts of their distributional range of even within their populations. The main aim of this thesis was to address the understudied aspects of polyploid speciation by employing new, convenient methods and/or studying plant model systems with unique features. Difference in monoploid genome size of Tripleurospermum inodorum (Asteraceae) cytotypes provided a unique opportunity for addressing the rate of spontaneous polyploidization in natural populations by enabling the easy distinction of neopolyploid mutants from long-established polyploids in routine flow-cytometric analyses. Repeated ploidy screening in mixed-ploidy populations of annual T. inodorum have been, to our knowledge, the very first attempt to document temporal changes in cytotype composition in situ. In spite of considerable between- year oscillations in cytotype frequencies, both diploids and tetraploids usually persisted locally for several consecutive years. The common incidence of such ploidy mixtures along with a partial fertility of triploid...
|
|
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Microevolutionary processes in mixed-ploidy populations of plants
Čertner, Martin
Polyploidization (whole-genome duplication) is widely considered one of the most important evolutionary forces driving the diversification of flowering plants. Polyploids tend to originate recurrently and many plant species retain individuals of two or more different ploidy levels in certain parts of their distributional range of even within their populations. The main aim of this thesis was to address the understudied aspects of polyploid speciation by employing new, convenient methods and/or studying plant model systems with unique features. Difference in monoploid genome size of Tripleurospermum inodorum (Asteraceae) cytotypes provided a unique opportunity for addressing the rate of spontaneous polyploidization in natural populations by enabling the easy distinction of neopolyploid mutants from long-established polyploids in routine flow-cytometric analyses. Repeated ploidy screening in mixed-ploidy populations of annual T. inodorum have been, to our knowledge, the very first attempt to document temporal changes in cytotype composition in situ. In spite of considerable between- year oscillations in cytotype frequencies, both diploids and tetraploids usually persisted locally for several consecutive years. The common incidence of such ploidy mixtures along with a partial fertility of triploid...
|
|
|
Microevolutionary processes in mixed-ploidy populations of plants
Čertner, Martin ; Kolář, Filip (advisor) ; Ramsey, Justin (referee) ; Duchoslav, Martin (referee)
Polyploidization (whole-genome duplication) is widely considered one of the most important evolutionary forces driving the diversification of flowering plants. Polyploids tend to originate recurrently and many plant species retain individuals of two or more different ploidy levels in certain parts of their distributional range of even within their populations. The main aim of this thesis was to address the understudied aspects of polyploid speciation by employing new, convenient methods and/or studying plant model systems with unique features. Difference in monoploid genome size of Tripleurospermum inodorum (Asteraceae) cytotypes provided a unique opportunity for addressing the rate of spontaneous polyploidization in natural populations by enabling the easy distinction of neopolyploid mutants from long-established polyploids in routine flow-cytometric analyses. Repeated ploidy screening in mixed-ploidy populations of annual T. inodorum have been, to our knowledge, the very first attempt to document temporal changes in cytotype composition in situ. In spite of considerable between- year oscillations in cytotype frequencies, both diploids and tetraploids usually persisted locally for several consecutive years. The common incidence of such ploidy mixtures along with a partial fertility of triploid...
|
|
|
Mechanisms driving di- and tetraploid coexistence in mixed-ploidy populations of Tripleurospermum inodorum
Nedomová, Anežka ; Čertner, Martin (advisor) ; Dostálek, Tomáš (referee)
Genome duplication plays a significant role in plant evolution. Formation of new polyploids is generally considered to be rare. Nevertheless, under natural conditions mixed-ploidy populations occur in relatively large numbers. Only the observations in the cytotype contact zone can identify all the factors affecting the stability or instability of the population. Number of research focusing on study of cytotype coexistence in natural mixed-ploidy populations is still low. As a model system for the study of mechanisms governing cytotype coexistence was chosen the Tripleurospermum inodorum. Research focused on natural mixed-ploidy populations and also on planted mixed-ploidy populations. Permanent plots were located in south, west, northwest and north Bohemia. Field observations were supplemented by cultivation experiments carried out in the greenhouse. Several phenomena were discovered at the level of whole populations. Cytotype distribution in the plot was random. The spatial structure of natural populations was quickly changing even within a single season. Even between single plot evaluations the cytotype ratios varied. Three percent of all plants were triploid hybrids. Most often detected cytotype in soil seed bank was diploid cytotype. The study of population dynamics shows, that tetraploids are...
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