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Anthropogenic hybridization between selected cultivated and wild relatives from the genus Malus (Rosaceae)
Orlovská, Lívia ; Slovák, Marek (advisor) ; Chrtek, Jindřich (referee)
Hybridization is an important driver of plant evolution, but it can also pose a threat to the genetic integrity of species. A specific case is gene flow induced by human activity, or "anthropogenic hybridization." In addition to theoretical knowledge about hybridization, introgression, and the protection of genetic diversity, this thesis presents its importance and impacts using the example of a model system from the Malus genus. By analyzing the available studies on the subject, I compare and evaluate the state of European populations of the wild species Malus sylvestris, which is subject to hybridization and introgression mainly with the cultivated species Malus domestica. The data indicate a common hybridization between these species to varying degrees, with up to 37 % of hybrid individuals in the population. The human effect is significant, particularly through the intensification of landscape utilization, which results in more frequent secondary contacts between species and subsequent gene flow. However, the available studies about hybridization between these species are mostly local, and a comprehensive view of the issue is lacking. Indeed, in the Czech Republic and Slovakia, there are presently no comparable empirical investigations utilizing genetic data. Overall, it implies that it is...
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Selected factors affecting species and genetic diversity of oribatid mites (Acari: Oribatida) in Central Europe
GALICOVÁ, Petra
The first part of the thesis focused on the impact of natural disturbances and subsequent management practices (natural regeneration vs. clear cutting) on the oribatid mites in the montane Norway spruce forest in Šumava National Park (Czech Republic). Our results showed that changes caused by logging after a natural disturbance could be evident even more than 15 years later, at least in oribatid mite communities. The results of a phylogeographic study of two closely related species are presented in the second part. Except for revealing distinct phylogeographic patterns in the populations of these species across Europe, one new species was discovered, and its morphological and genetic description is provided.
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Migrations in the African Sahel through the view of the genetic diversity of control segment of mitochondrial DNA
Adámková, Kristýna ; Černý, Viktor (advisor) ; Frynta, Daniel (referee)
Sub-Saharan Africa is the region with the highest diversity of anatomically modern humans (AMH). With the use of genetic analysis of mostly uniparental loci, gradually we can uncover the migratory activity of humans long time ago. This work focuses on the African Sahel. It is a long, horizontal strip bordered by the Sahara Desert and tropical rainforests across the entire continent. Favorable environmental conditions and the absence of a geographical barrier are suitable not only for mobile herders, but also for sedentary farmers. These provisos create high migration aktivity in the area. In this work, I newly sequenced 474 mitochondrial DNA samples of 11 populations. Populations of pastoralists and farmers are spread all over Sahel/Savannah belt. Intrapopulation analysis assessed diversity within the population and generally showed low values in pastoral populations, especially Fulani pastoralists in the western Sahel. Interpopulation analysis revealed bigger differences between individual populations than between populations clustered in the subsistence group of pastoralists or farmers, within regions or within language. The work included populations with Afro-Asiatic, Niger-Congo and Nilo-Saharan language families. Thanks to the Migrate-n program, in this work I was able to confirm the...
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Evolution of the genus Arabidopsis in its centre of diversity
Šrámková, Gabriela
A prerequisite for addressing general questions concerning the evolution of intraspecific variability in space and time is the knowledge of the distribution of variability within the species' range. The development of molecular methods has been a major step forward, allowing various evolutionary questions to be addressed using natural populations of model species and their close relatives. Although wild relatives of Arabidopsis thaliana have long been in the focus of plant evolutionary biologists and molecular geneticists, the patterns of genetic diversity and phenotypic variation in their natural populations are often overlooked. The present work focuses on some of the most studied model species in the Brassicaceae family, Arabidopsis halleri and the complex of A. arenosa, whose members are widely used to study ecology, physiology and evolution as well as the molecular basis of phytoremediation and parallel adaptation. The study aimed to determine intraspecific variation at the ploidy level, to reveal phylogenetic relationships and the spatial distribution of genetic diversity across the range, and to propose a new taxonomic concept based on the detected intraspecific genotypic and phenotypic variation. In order to accomplish this goal, we used DNA flow cytometry, several molecular methods (AFLP,...
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Telestes perspective on the karstic poljes of eastern Herzegovina
Doulíková, Tereza ; Vukićová, Jasna (advisor) ; Choleva, Lukáš (referee)
The Dinaric karst region in the Balkans is one of the hot spots of biodiversity with a high number of endemic freshwater fish. The major cause of the high degree of endemism are numerous paleoclimatic and geological events that have affected the formation of the entire area. Flows of karst poljes represent a specific ecosystem to which some fishes have adapted. The poljes have been periodically flooded and these floods may activate different underground channels, which lead to interconnection of poljes. These fish species spend a part of the year in surface water and a part in groundwater and they may use the underground flows between poljes for migration. The aim of this thesis is to evaluate the genetic variability of two endemic fish species of the genus Telestes living in karst poljes in the region of eastern Herzegovina, and to detect a possible current gene flow between populations of these species due to the connection of underground flows. For this purpose, the DNA from 102 individuals from five different localities was isolated. The mitochondrial marker cytochrom b and 16 microsatellite loci were used for the analyses. The results point to very low variability between species and populations. Based on mitochondrial marker analysis, no link between populations of the species was detected,...
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Diversity of Blastocystis (Stramenopiles) in reptiles and arthropods
Lorencová, Markéta ; Čepička, Ivan (advisor) ; Jirků, Kateřina (referee)
The genus Blastocystis has recently attracted the attention of scientists, especially parasitologists. Similarly to the related opalines and proteromonads, Blastocystis is anaerobic and lives endobiotically in the intestine of various animals. This organism is also often found in humans, where it is associated with irritable bowel syndrome, though its pathogenic potential remains uncertain. The genus Blastocystis is remarkable for its rich genetic diversity. The taxonomy of Blastocystis is inconsistent and problematic. The strains isolated from homoiothermic vertebrates are divided into 17 subtypes, while strains from poikilotherms are either classified as separate species or are not considered in taxonomic studies at all. The aim of the study was to further examine the genetic diversity of the genus Blastocystis. We determined SSU rDNA sequences of 38 strains isolated from poikilothermic vertebrates and arthropods. The results of our phylogenetic analysis showed that Blastocystis is considerably diverse in these hosts, and we defined 21 new subtypes. The total number of known subtypes of Blastocystis has thus increased to 38. We also examined light-microscopical morphology of some strains. Most of the newly defined subtypes show identical morphology, ST20 (Blastocystis geocheloni) is an exception,...
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Impact of river system structure on the genetic diversity of reed populations
Fuxová, Gabriela ; Fér, Tomáš (advisor) ; Kubátová, Barbora (referee)
Many plant species are closely related to river biotopes or to biotopes influenced by rivers. River systems create important linear corridors in ecosystems and directly or non-directly influence spatial spread of species in these environments. This offer many questions about species spread in this system. We can answer these questions by using molecular methods. Using 10 microsatellite (SSRs) primers, 202 individuals of Phragmites australis from 60 populations were analysed. Those analyses allowed reveal kinship of individuals, obtain information about spatial spread of populations and about spreading of common reed. Phragmites australis creates both - monoclonal and polyclonal - populations. Dependence of rate of clonality on environment was revealed. Populations from river banks are more monoclonal, populations from pond shores are more polyclonal. Populations are isolated. The highest percentage of variability was explained on among-population level. This is common for anemochoric species. Communication between populations is present, more on shorter distances. Evidence for vegetative spread was found on short distance. Generative spread is much more common. Long-distance spreading is mediated by generative diaspores - seeds. This spreading includes within-river spread, among-river spread and spreading...
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The genetic links around the Red Sea as revealed by the mtDNA
Čížková, Martina ; Černý, Viktor (advisor) ; Rídl, Jakub (referee)
The Red Sea region is one of the important places that allow us to uncover traces of the evolution of anatomically modern humans. Besides the questions related to its expansion out of Africa, this region is also important in terms of the mutual influence between populations of Africa and Arabia that after a long period of isolation and genetic differentiation related to climate change in the Pleistocene and subsequent development of seaways and land routes in the Holocene began to contact with each other more frequently. Number of genetic analyzes has been done but some issues concerning on the later development still remain inadequately answered, mainly because of insufficient material. This work is focused on the analysis of 200 mtDNA sequences of four Sudanese populations - two populations of nomadic herdsmen Rashaida and Beja living in the close neighborhood around the city of Kassala and speaking different languages and two populations of the Nile Valley with settled way of life. Analysis of the intrapopulation level revealed much higher diversity of the sedentary populations (in this work the sedentary populations are represented by the Nubians and Arabs). Interpopulation variability and genetic distances within other 46 populations of the Red Sea showed that although Rashaida and Beja people...
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Evolution of the genus Arabidopsis in its centre of diversity
Šrámková, Gabriela ; Marhold, Karol (advisor) ; Greimler, Josef (referee) ; Mártonfi, Pavol (referee)
A prerequisite for addressing general questions concerning the evolution of intraspecific variability in space and time is the knowledge of the distribution of variability within the species' range. The development of molecular methods has been a major step forward, allowing various evolutionary questions to be addressed using natural populations of model species and their close relatives. Although wild relatives of Arabidopsis thaliana have long been in the focus of plant evolutionary biologists and molecular geneticists, the patterns of genetic diversity and phenotypic variation in their natural populations are often overlooked. The present work focuses on some of the most studied model species in the Brassicaceae family, Arabidopsis halleri and the complex of A. arenosa, whose members are widely used to study ecology, physiology and evolution as well as the molecular basis of phytoremediation and parallel adaptation. The study aimed to determine intraspecific variation at the ploidy level, to reveal phylogenetic relationships and the spatial distribution of genetic diversity across the range, and to propose a new taxonomic concept based on the detected intraspecific genotypic and phenotypic variation. In order to accomplish this goal, we used DNA flow cytometry, several molecular methods (AFLP,...
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