|
| |
|
|
Molecular cztogenetic analysis of adaptive radiation in the gecko genus Paroedura (Squamata:Gekkota)
Koubová, Martina ; Kratochvíl, Lukáš (advisor) ; Šťáhlavský, František (referee)
Paroedura genus includes 17 described species endemic to Madagascar and the Comoros Islands, where they went through a significant adaptive radiation. The genus Paroedura is monophyletic and well supported hypothesis on phylogenetic relationships among its species was published. Species vary considerably in body size and morphology and in preferences for habitat, some species live in sympatry. The genus Paroedura belongs to cytogenetically poorly studied family Gekkonidae which exhibits high variability in modes of sex determination and in comparison with basal gecko lineages, also considerable variability in the chromosome number and morphology. Karyotypes of only two species of the genus (P. picta, P. sp.) have been published. The aim of my thesis was to describe karyotypes of both sexes in all available species of the genus using conventional and molecular cytogenetic methods, to perform the phylogenetic analysis of karyotype evolution and chromosomal rearrangements in the genus, to assess the role of these rearrangements in the speciation of the genus and to detect sex chromosomes. I acquired karyotypes of both sexes in nine species representing the most of major phylogenetic lineages of the genus. According to the results, species can be divided into three groups according to diploid...
|
|
|
Evolution of karyotype and sex determination in iguanas (Squamata: Pleurodonta)
Altmanová, Marie ; Kratochvíl, Lukáš (advisor) ; Zrzavá, Magda (referee)
Squamate reptiles in general possess an unusual variability in karyotype and sex determining mechanisms. However, in these two aspects, iguanas (Pleurodonts) are considered as a relatively conservative group of lizards. So far only genotypic sex determination with male heterogamety has been detected in this lineage. However, the sex chromosomes have not been revealed in many species by classical cytogenetics, probably due to their homomorphy. Significant variability in karyotype was observed only in the species-rich genera Anolis, Sceloporus and Liolaemus. The aim of this thesis was to investigate the genome of available species from the main iguanid lineages using classical and molecular cytogenetic methods. As well as finding the karyotype characteristics, which may represent synapomorphies of main iguanid lineages, the other aim was to try to identify sex chromosomes. This study confirmed previously published karyotypes of 13 species and established new descriptions of karyotype for eight species. The chromosomes of all studied specimens were examined by methods of classical and molecular cytogenetics, 21 species covering eight iguanid families were analysed in this thesis. The majority of studied species shared the apparently ancestral karyotype of the group, with diploid chromosome number...
|
|
|
Evolution of sex chromosomes and karyotypes in geckos (Squamata: Gekkota)
Koubová, Martina ; Kratochvíl, Lukáš (advisor) ; Choleva, Lukáš (referee)
Gekkota is species-rich and diverse group of squamate reptiles (Reptilia: Squamata) with almost global distribution. There were many hypothesis defined about the phylogeny of this group, traditionally based on morphological data. The essential reversal in phylogenetic relationships occurred with the entry of molecular analysis, whose differ in their conclusions from traditional approach fundamentally, even in positions of mayor lineages. This fact has an essential importance for the karyotype evolution study of this group. The ancestral state is considered as 2n=38 karyotype with all chromosomes acrocentric. In some species is this karyotype kept, in another there is apparent an influence of chromosome changes, mostly Robertsonian fusions and pericentric inversions. Diploid chromosome number is from 16 to 46, but the most common is 2n=38 karyotype of mostly acrocentric chromosomes, gradually decreasing in size. The interesting character of this group is extraordinary variability in sex determining mechanisms. We can find there species with temperature sex determination and also species with genotypic sex determination (both types XX/XY and ZZ/ZW). Sex chromosomes data are documented in only 17 species. Sex chromosomes differ rapidly in their morphology and their homology between sister taxa was not proved...
|
|
|
Comparative cytogenetics of bed bug Cimex lectularius (Heteroptera: Cimicidae)
Sadílek, David ; Vilímová, Jitka (advisor) ; Ráb, Petr (referee)
Comparative cytogenetics of the bed bug Cimex lectularius (Heteroptera: Cimicidae) The human bed bug Cimex lectularius has started enormous spreading to all developed countries of temperate climate zone during the last ten years. Bed bug was almost eradicated by a mass use of DDT in these areas until the 70's in the 20th century. This temporal haematophagous ectoparasite occupies particularly human dwellings and bat roosts. Cimex lectularius shows unusual combination of cytogenetic characteristics, general for all Heteroptera, however, not usual for other organisms. The chromosomes are holokinetic, with completely achiasmatic meiosis and inverted meiosis of the sex chromosomes. Especialy remarkable feature is intraspecific variation of the number of the X chromosomes. The variable number of chromosomes of 43 populations of Cimex lectularius from the Czech Republic and 27 populations from other European countries was studied in the present study. The 10 variants of karyotype were found out by using the "hotplate spreading" method and the standard Giemsa staining. There were male karyotypes with 2n = 29, 30, 31, 32, 33, 34, 35, 37, 42 and 47 chromosomes and two females with peculiar odd number of sex chromosomes X, 2n = 33 and 43, not complementary with any male. A stable number of 2n = 26 autosomes...
|
|
|
Karyotype differentiation of Euscorpius scorpions (Scorpiones: Euscorpiidae) in Europe
Novotný, Tomáš ; Šťáhlavský, František (advisor) ; Ráb, Petr (referee)
The aim of presented work is to provide characteristics of the karyotypes of scorpions of the genus Euscorpius. Genus Euscorpius is a typical representative of scorpions in Europe. Its occurrence is wide throughout Europe. Until now, 18 species of this genus have been described. In this work six species were karyologically analyzed and one species was shown to possess only basic diploid number of chromosomes: E. carpathicus - 2n=90, E. concinnus - 2n=88, E. hadzii - 2n=68, E. sicanus - 2n=66, E. tergestinus - 2n=60, E. naupliensis - 2n=60, E. italicus - 2n=36. Description of the karyotypes revealed that all species studied exhibit achiasmatic meiosis; no presence of sex chromosomes was detected. The basic hypothesis of phylogenetic relationships and karyotype evolution of the genus Euscorpius was outlined. High interspecies variability in chromosome total count was found and by analysis of the 16S rRNA gene the taxonomic status of the species was confirmed. Hence, it seems that cytogenetic methods can contribute to the understanding of species diversity and differentiation of possible cryptic species within the genus Euscorpius.
|
|
|
Cytogenetics and biology of selected representatives of the family Sphaeriidae
Kořínková, Tereza ; Juřičková, Lucie (advisor) ; Reise, Heike (referee) ; Marec, František (referee)
"Cytogenetics and biology of selected representatives of the family Sphaeriidae" Mgr. ing. Tereza Kořínková Abstract of a PhD. thesis The thesis has a form of four separate articles, the full texts of which are included. Two of them were published, one was accepted and one was under revision before submission of the PhD thesis. The articles deal with cytogenetics, breeding and nutrition of selected representatives of the hermaphroditic, viviparous, primarily freshwater bivalves of the family Sphaeriidae (Mollusca: Bivalvia: Veneroida). Although various aspects of the biology of Sphaeriidae have been intensely studied for more than 100 years, many questions still remained unresolved. This thesis brings data on chromosome numbers of 11 species(10 of which have not been studied cytogenetically before) and information on the course of meiosis in two of these species (Chapter 1). Although the chromosome numbers are high (from ca. 140 to more than 240), the behaviour of chromosomes at meiosis rather corresponds to that of diploid organisms. Also the DNA contents in five selected species with high chromosome numbers (as measured by flow- cytometry) do not differ significantly from those in sphaeriids with a diploid chromosome number of 30. Such results contradict an origin of the high chromosome numbers by a...
|
|
|
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.
|
|
|
Possibility of DNA probes preparation for want of CMG
Krejčí, Jana ; Bártová, Eva
The main method of cytogenetics is the DNA fluorescence in situ hybridization (DNA-FISH), where DNA probe links to the specific locus of genome. In our laboratory, DNA probes are prepared from DNA amplified by bacterial vector (PAC/BAC). The following step is exploiting Nick-translation reaction for incorporation of reporter molecule targeted for antibody conjugate with fluorescence molecule. Specificity of prepared DNA probe is increased using Cot-DNA, which suppress the repetitive sequences.
|
|
| |
guest ::
