My dissertation explores several aspects of the relationship between morphological and molecular evolution in amoeboid lineages: Chapter 1 - General Introduction: This chapter provides an overview of the most pressing issues in Amoebozoa phylogeny that are dealt with in the remainder of the thesis Chapter 2 - Reducing the impact of PCR-mediated recombination in molecular evolution and environmental studies using a new generation high fidelity DNA polymerase: This chapter addresses the methodological difficulty in the study of large gene families, the generation of artifactual sequences by recombination during PCR. Chapter 3 - Evolution of the actin gene family in testate lobose amoebae (Arcellinida) is characterized by two distinct clades of paralogs and recent independent expansions: This chapter explores intriging patterns of evolution in the actin gene families of testate amoebae. Chapter 4 - Comprehensive phylogenetic reconstruction of Amoebozoa based on concatenated analysis of SSU-rDNA and actin genes: A deep phylogenetic analyses of the Amoebozoa, enables exploration of well supported taxonomic units within the group. Chapter 5 - Interpreting the evolutionary history of the Tubulinea (Amoebozoa), in light of a multigene phylogeny: This chapter explores a more restrict taxonomic unit within the Amoebozoa - the Tubulinea - based on an expanded sample of genes and taxa. Chapter 6 - The chastity of amoebae: re-evaluating evidence for sex in amoeboid organisms: This chapter asks whether the null-hypothesis that amoebae are asexual is consistent with current phylogenetic evidence

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 5 uppsatser. På titels. felaktigt: 1997.

Univerzita Karlova v Praze Přírodovědecká fakulta Studijní program: Molekulární biologie, genetika a virologie Bc. Jan Röslein Mutační a substituční tempo u sexuálních a klonáních forem: možný klíč k vysvětlení persistence sexu u modelové skupiny sekavců Mutation AND substitution rates in sexual and asexual forms: a clue to the persistence of sex in a model group of Cobitis? Typ závěrečné práce Diplomová Vedoucí závěrečné práce: Mgr. Karel Janko, Ph.D. Praha, 2015 Velký dík náleží mému školiteli Mgr. Karlu Jankovi, Ph.D. za velmi nápomocné, direktivní vedení práce. Též bych rád poděkoval panu Mgr. Janu Pačesovi, Ph.D. za více než vzdělávací rozměr v oblasti bioinformatické analýzy a Mgr. Ladislavu Pekárikovi, Ph.D., Mgr. Janu Kočímu za pomoc při analýze vybraných kapitol. Také bych rád poděkoval rodině za podporu. Všem participantům na této diplomové práci se hluboce omlouvám za způsobenou psychickou újmu. Prohlášení: Prohlašuji, že jsem závěrečnou práci zpracoval/a samostatně a že jsem uvedl/a všechny použité informační zdroje a literaturu. Tato práce ani její podstatná část nebyla předložena k získání jiného nebo stejného akademického titulu. V Praze dne 12. 8. 2015 Podpis: Abstrakt Klíčová slova: Abstract Key words: Obsah 1...

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...

TITLE: Mutation and substitution rates in sexual and asexual forms: a clue to the persistence of sex in a model group of Cobitis? AUTOR: Jan Röslein DEPARTMENT: Ústav živočišné fyziologie a genetiky AVČR, v.v.i. SUPERVISOR: Mgr. Karel Janko, Ph.D. ABSTRACT: Subject of this thesis is to test several hypotheses about the evolution of asexual reproduction in model group of fish family Cobitis and its mutual competition among sexual and asexual forms, which touches one of the oldest unresolved issues of biology. Specifically, the work deals with the accumulation of non-synonymous mutations, which accelerated accumulation in the genome of clonal lineages theoretically leads to increased extinction compared with sexually reproducing populations (so-called. The theory of Muller's ratchet and Kondrashov's hatchet). This thesis is based on a normalized cDNA sequencing data from oocytes and liver tissue, which has served as a base matrix (generated based on non-normalized cDNA data) for transcriptome sequencing (RNAseq). Consequently, the RNAseq data have served as validation for acquired polymorphisms, detection of differential expression of allele- specific expression (ASE) hybrid biotypes. This diploma thesis balances among the edges of vast spectrum of hypotheses regarding the evolution of the genus hybrid...

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...

Sex determination among reptiles is a very variable matter across it's taxa. We meet there temperature sex determination and genotypic sex determination with many independent transitions between them. It is a group suitable to study evolution of sex determination, sex chromosomes and sex determination genes. Rare cases of sex reversal caused by extreme incubation temperature or exogenous hormones have been reported in recent years. In case of Acrodont lizard, Pogona vitticeps, was reported sex reversal caused by high incubation temperatures. Our purpose was to repeat the experiment, mainly due to insufficient conclusiveness of used methods. We wanted to expand the experiment by hormonal reversal, studying persistence of sex reversal to maturity and fertility of reversed individuals. We managed successfully to demonstrate sex reversal in both treatments by histological examination. Individuals with discordant phenotypic and genotypic sex were breed till one year of life, which demonstrate persistence of reversal. Our outcomes are concordant with most recent work on this species and show full functional phenomenon of sex reversal with reptiles, which studying could contribute to our understanding of evolution of sex determination.