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"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...

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.

This master's thesis is focused on cytogenetic analysis and karyotype variability of the Nemastomatidae family. This family comprises morphologically uniform harvestmen of small sizes, with low mobility, and with center of distribution in Europe. Karyotype differences could play an important role for detection of cryptic diversity in this family. The karyotype analysis is focused mainly on Alpine and Pyrenean endemic species but also on other taxons located in Central Europe. The goal was not only to identify the differences which occur between the specific genera and species, but also eventually between populations. For detection of the specific chromosomal alterations in evolution of the karyotype in Nemastomatidae the fluorescent in situ hybridization (FISH) was used, localizing the positions and amounts of gene clusters for 18S rRNA. From the results we can assume that the number of chromosomes in the family Nemastomatidae can range between 2n = 12- 30. Further it was found out that in Nemastomatidae the biarmed chromosomes are more prevalent, and that the species which have lower amounts of chromosomes contain chromosomes that noticeably differ in size (probably because of chromosomal fusions). These results indicate that with some morphologically uniform species, the knowledge of specific...

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....

The genome size of evolutionary polyploid, neopolyploid and hybrid sturgeons is well known for its high variability. Aim of this study was 1) to specify the genome size of polyploid and neopolyploid sturgeons using an analysis of 2-D and 3-D images of specifically stained cells nuclei, 2) to evaluate the samples of populations for cytogenetic analysis needs and thereafter, 3) to compare both methods and record the data either for next research or for negative selection from the broodstock. This test has been done at the laboratory of molecular, cellular and quantitative genetics, Faculty of Fisheries and Protection of Waters USB in Vodňany using all sturgeons spawners and using samples obtained from some foreign fish farms which cooperated with the faculty. The samples included A. ruthenus, A. baerii, A. stellatus, A. gueldenstaedtii and Huso huso, intentionally bred hybrids of A. gueldenstaedtii (8n) x A. baerii (12n), A. baerii (8n) x A. ruthenus (4n), A. gueldenstaedtii (8n) x A. baerii (10n) a A. gueldenstaedtii (8n) x A. ruthenus (4n). As methods have been chosen image cytometry and confocal microscopy which use image digitalization and subsequently its computer analysis. The genome size was measured from the size of specifically stained nuclei of erythrocytes in specimens sampled. Result of this study was measuring the genome size in sturgeons under study using different methods, recording the obtained data, description of spatial conformation changes of cell nucleus with increasing ploidy level and deduction of impact to their physiology and comparing the methods between each other. The conclusion is necessity of another sturgeons genome size determination , choice of the best methods for more effective search and research of non-standard individuals and subsequently an examination of their physiological differences.

(English) Sex determination plays an important role in the viability of populations and species evolvability. This is one of the reasons why sex determination has become an important subject of many studies during more than the last 100 years. The thesis focuses on the evolution of sex determination systems in toxicoferan reptiles. Toxicofera is a group of squamate reptiles containing more than 6000 species. Their species richness is also reflected in the diversity of their sex determination systems. The presence of environmental sex determination (ESD) as well as genotypic sex determination (GSD) with either XX/XZ or ZZ/ZW sex chromosomes, was reported among the toxicoferan species; however, the current knowledge on sex determination in toxicoferan reptiles is not equally distributed across their lineages. The main aim of the theses is to expand our knowledge on sex chromosome evolution using cytogenetic methods in snakes, chameleons and anguimorphan lizards. The first part of the thesis deals with the sex chromosome evolution in caenophidian and henophidian snakes. It is focused mainly on the variability in the distribution of repetitive content as well as heterochromatinization of the W chromosome of caenophidian snakes. While the sex chromosomes of Caenophidia are cytogenetically quite well...

The present thesis deals with the phenomenon of additional sex chromosomes in Cimex lectularius (Hemiptera: Heteroptera: Cimicidae) using genome size analysis combined with the classical cytogenetic approach. Also, five other cimicid species and 12 species from the family Nabidae were analysed identically for comparative purposes. The thesis also pursues a description of methodical approaches of cytogenetics and flow cytometry in the study of C. lectularius. Recently analysed European specimens of C. lectularius from human host exhibited 12 distinct cytotypes, with a variable number of chromosomes X from two to 20 (2n♂ = 26+X1X2Y to 26+X1-20+Y). The fragmentation hypothesis of C. lectularius additional chromosomes X origin was established in the second half of the 20th century. However, the present genome size measurements suggest that various chromosomal rearrangements as duplication or deletion besides the fragmentation could occur. Males with basic cytotype 2n = 26+X1X2Y had average genome size of 2C = 1.94 pg, in contrast male with 2n = 26+X1-7+Y yielded 2C = 2.26 pg and also specimens with genome size decrease 2C = 1.69 pg appeared. The most informative turned up to be the relative genome size of sperm cells n = 13+X1X2 and n = 13+Y, where specimens with higher chromosome number showed...

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...

- ABSTRACT - Among vertebrates, reptiles represent the ideal group for the study of sex determination. Reptiles include lineages with environmental sex determination (ESD) as seen in crocodiles and tuatara, lineages with genotypic sex determination (GSD), like e.g. iguanas, chameleons, skinks, lacertid lizards and birds, and few groups which possess variability in sex determination mechanisms, i.e. geckos, dragon lizards and turtles. This thesis is focused on the evolution of sex chromosomes and sex determination in turtles. The majority of turtle species exhibit ESD, which is considered the ancestral sex determination system of this group, while GSD either as male or female heterogamety evolved independently at least five times. We investigated the presence of sex chromosomes in representative species of turtles by cytogenetic analyses. The analyses included the reconstruction of karyotypes, distribution of constitutive heterochromatin (C-banding, methylation analysis) and repetitive elements (fluorescence in situ hybridization) and comparative genome hybridization (CGH), which often characterize the degenerated Y or W and can be helpful in the identification of "cryptic" sex chromosomes. We described XX/XY sex chromosomes in seven previously unstudied Australasian chelids (Pleurodira) from the genera...