National Repository of Grey Literature 43 records found  previous11 - 20nextend  jump to record: Search took 0.01 seconds. 
Coevolution of Cartesian Genetic Algorithms and Neural Networks
Kolář, Adam ; Král, Jiří (referee) ; Zbořil, František (advisor)
The aim of the thesis is to verify synergy of genetic programming and neural networks. Solution is provided by set of experiments with implemented library built upon benchmark tasks. I've done experiments with directly and also indirectly encoded neural netwrok. I focused on finding robust solutions and the best calculation of configurations, overfitting detection and advanced stimulations of solution with fitness function. Generally better solutions were found using lower values of parameters n_c and n_r. These solutions tended less to be overfitted. I was able to evolve neurocontroller eliminating oscilations in pole balancing problem. In cancer detection problem, precision of provided solution was over 98%, which overcame compared techniques. I succeeded also in designing of maze model, where agent was able to perform multistep tasks.
Karyotype evolution of selected families of entelegyne spiders
Kotz, Matěj ; Král, Jiří (advisor) ; Nguyen, Petr (referee)
The Araneoidea superfamily is a diverse clade of spiders with a great species diversity. The whole superfamily displays considerable conservativeness of observed karyotypes. Most likely ancestral karyotype in males is 24 acrocentric chromosomes with X1X2 sex determination system. The goal of this study is to explore the karyotype diversity of two araneoid families - Araneidae and Mimetidae. The majority of studied species exhibit the ancestral karyotype. In some species of the aformentioned families was observed sudden increase in chromosome numbers, up to 2n♂ = 52 in Araneidae and up to 2n♂ = 57 in Mimetidae. The latter number is the highest chromosome count observed in Entelegynae so far. Increase in 2n goes hand in hand with increase in sex chromosome numbers, leading up to X1X2X3X40 system in Araneidae and up to X1X2X3X4X5X6X70 in Mimetidae. I suggest polyploidy as a possible mechanism of the increase. To test this hypothesis, I measured the size of the genome using flow cytometry and used fluorescence in situ hybridization for the detection of 18S rRNA and 5S rRNA genes. For one species, probe for U2 snRNA gene was also optimized as part of this thesis. In many species studied, these techniques were used for the first time ever. In the case of the family Mimetidae, the largest genomes in...
Karyotype evolution in estrildid finches of the genus Lonchura
Janáková, Šárka ; Reifová, Radka (advisor) ; Augstenová, Barbora (referee)
The karyotype, the set of all chromosomes in a cell, is an important characteristics of individual species of both animals and plants. The karyotype of birds is typically stable in terms of the number of chromosomes and their size, and rearrangements between different chromosomes are rare. The changes that occur between the karyotypes of avian species are more often intrachromosomal, such as inversions or duplications and deletions. It is still unclear how often such changes occur between closely related species and whether they can contribute to speciation. This work aims to compare the karyotypes of a total of five closely related species of songbirds of the genus Lonchura (munias and mannikins). Comparing chromosomal changes in such recently diverged species allows us to observe changes that might contribute to speciation. The study is based on karyotype analysis by immunofluorescence staining of synapsed pachytene chromosomes and subsequent identification and comparison of chromosome types. This method allows determination of the changes that are manifested by pericentric inversions where the position of the centromere is changed. The results confirm the general idea of avian karyotypes as very conservative in terms of chromosome number and their sizes. However, in some chromosomes we observed...
Giardia intestinalis karyotypes
Hudosová, Lenka ; Nohýnková, Eva (advisor) ; Král, Jiří (referee)
Giardia intestinalis is a parasitic protist that causes one of the most common diarrheal disease of parasite origin. The cell of Giardia contains two nuclei with unknown number of chromosomes until recently. Karyotype was determined five years ago using conventional cytogenetic method by Tůmová and collaborators. In my work, I assessed karyotype of four isolates, six lines and three clonal lines by the same method. It was confirmed, that two nuclei within one cell could differ in chromosome number, the differences found were 1, 2 or 6 chromosomes. Aneuploid number of chromosomes was found too. In case that both nuclei within single cell contained the same number of chromosomes, there were 10 chromosomes indentified in each nucleus. It was also revealed, that karyotype is not specific feature for different genetic groups (in this work assemblages A and E). Karyotype can be different even among lines and clonal populations derived from the same isolate. Changes in karyotype in the course of in vitro cultivation were detected within three populations. Results are discussed in relation to known facts.
Karyotype analysis of selected representatives of two pedipalpid orders, Amblypygi and Uropygi
Sember, Alexandr ; Král, Jiří (advisor) ; Ráb, Petr (referee)
Karyotype analysis of selected species from arachnid orders Amblypygi and Uropygi Whip spiders (Amblypygi) and whip scorpions (Uropygi) represent relict arachnid orders which has been found already at Upper Carboniferous strata. Although cytogenetic data from amblypygids and uropygids might be important to reconstruct karyotype evolution of arachnids, cytogenetics of these orders is almost unknown. Presented study is aimed in analysis of karyotype and meiosis in 16 species of Amblypygi and 4 species of Uropygi. Both groups are characterized by considerable range of diploid chromosome numbers (2n = 24 - 86 in Amblypygi and 36 - 66 in Uropygi). Analysed species does not exhibit morfologically differentiated sex chromosomes. Differentiation of sex chromosomes on molecular level was revealed in amblypygid Paraphrynus mexicanus by comparative genome hybridization. Obtained data indicate XY/XX sex chromosome system in this species. Comparison of karyotype data indicates reduction of chromosome numbers during evolution of both orders. In Amblypygi, this reduction was accompanied by increase of number of biarmed chromosomes. This trend is not apparent in Uropygi. Karyotypes of most analysed amblypygids and uropygids are also characterized by low amount of heterochromatin. Most studied species exhibit two pairs...
Evolution of sex determination in skinks and related lineages
Kostmann, Alexander ; Rovatsos, Michail (advisor) ; de Bello Cioffi, Marcelo (referee) ; Liehr, Thomas (referee)
6 Abstract Scincoidean lizards, i.e. cordylids, gerrhosaurids, skinks and xantusiids, are known for their remarkable ecological and morphological variability. It was hypothesized that, at least in skinks, sex determining systems are highly variable as well. In the other three families, evidence for presence or absence of sex chromosomes has been scarce, with two species of night lizards with ZZ/ZW sex chromosomes being the exception. In this thesis, conventional and molecular cytogenetic methods, including C-banding, fluorescence in situ hybridization (FISH) with probes for telomeric motifs and rDNA loci and comparative genomic hybridization (CGH) were used to identify cytogenetically distinguishable sex chromosomes. Although most studied species showed no sex-specific differences by cytogenetic examination, some did. Tracheloptychus petersi has accumulations of rDNA loci on a pair of macrochromosomes and a pair of microchromosomes in males, while again on a pair of macrochromosomes and a single microchromosome in females. This distribution suggests a ZZ/ZW system in this species, which is the first report of sex chromosomes in any gerrhosaurid lizard. In Zonosaurus madagascariensis, CGH was able to identify the W chromosome in females, which is the second report of sex chromosomes in this family....
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
Karyotype evolution of the family Araneidae
Pajpach, Filip ; Král, Jiří (advisor) ; Sember, Alexandr (referee)
Orb-weavers (Araneidae) are a diversified spider family comprising more than 3,100 species in more than 170 genera. Together with 13 other families, they con- stitute to superfamily Araneoidea. The presented thesis focuses on karyotype evo- lution of Araneidae, including its comparison with a related family Tetragnathidae. The results obtained from 19 araneid and four tetragnathid species confirm previ- ously postulated hypothesis that the ancestral karyotype of Araneoidea (including Araneidae) consists of 24 acrocentric chromosomes in males, including two acro- centric X chromosomes of system X1X20. However, there is a tendency of 2n decrease in some araneids due to centric fusions. In these cases, centric fusions affected most autosomes (and sometimes gonosomes as well); number of chromosome pairs de- creased from 11 to six. Three independent reduction events were detected in this thesis. Furthermore, pattern of nucleolar organizer regions (NORs) was studied in this thesis using fluorescent in situ hybridization, since data on evolution of this marker are scarce in spiders. Striking variability in NORs number was discovered, ranging from one to 13 loci. Remarkably, multiple centric fusions were always ac- companied by considerable increase of NORs number. In araneids and tetragnathids possessing...

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