|
| |
|
|
Evolution of sex-determining mechanisms and genomes in squamate reptiles (Reptilia: Squamata)
Pokorná, Martina ; Kratochvíl, Lukáš (advisor) ; Marec, František (referee) ; Vyskot, Boris (referee)
Evolution of sex determining mechanisms in squamate reptiles (Reptilia: Squamata) Martina Pokorná Ph.D. thesis Abstract This Ph.D. thesis is focused on the evolution of sex determining mechanisms and genomes in squamate reptiles. It is based on three published articles and two manuscripts. The evolution of sex determining mechanisms, sex chromosomes and genomes, and their organisation, was studied on a wide phylogenetic scale of the whole group of squamate reptiles and some lineages of other Sauropsids, as well as on the small phylogenetic range as a detailed comparative study inside individual lineages of squamates. This thesis is based upon the use of classical cytogenetic methods, methods of molecular cytogenetic (especially fluorescent in situ hybridisation) and the results were analysed using phylogenetic approaches. The results and outputs of this study represent an important contribution to the general knowledge of the principals of sex determination and the evolution of these phenomena not only in squamate reptiles but also in the whole group of amniotes. Using the results obtained during the work on this thesis we can conclude that sex chromosomes evolved in particular lineages of amniotes independently. This origin was in some cases followed by accumulation of microsatellite sequences on sex...
|
|
|
Structure and evolution of plant sex chromosomes: The use of BAC library
Kejnovský, Eduard ; Lengerová, Martina ; Hobza, Roman ; Široký, Jiří ; Vyskot, Boris
Sex chromosomes of plant species Silene latifolia are the ideal model for evolutionary biology studies because they represent early stages of X and Y chromosomes history. We used fluorescence in situ hybridization (FISH) with bacterial artificial chromosome (BAC) clones in studies of chromosome structure to demonstrate that a majority of genes are located in subtelomeric regions of all chromosomes. Our results also indicate the absence of accumulation of main classes of repetitive sequences - retroelements and centromeric tandem repeats - in non-recombining parts of the sex chromosomes.
|
|
|
Genomic imprinting
Vyskot, Boris
Genomic imprinting represents an epigenetic marking of genes that results in their monoallelic expression, namely in mammals and flowering plants. Here, I also summarize our recent experiments describing the role of DNA methylation and histone H4 acetylation in plant reproductive development.
|
|
|
Genetic and epigenetic acpects of sex determination
Janoušek, Bohuslav ; Hodurková, Jaromíra ; Žlůvová, Jitka ; Lengerová, Martina ; Hobza, Roman ; Nix, Tomáš ; Vyskot, Boris
The article concentrates on the latest knowledge concerning the role of epigenetic mechanisms in sex determination in model dioecious species Silene latifolia. Results suggest that the locus suppressing development of female organs in male plants is hypersensitive to the action of agents influencing level of DNA methylation (5-azacytidine) and histone acetylation (trichostatin A). According to the results obtained via inter-specific hybridisation and the ability of the smut Ustilago violacea to activate development of male organs in female plants, it can be deduced that there is a locus suppressing male organ development in standard female plants. Function of this locus is not influenced by the drugs mentioned above.
|
|
| |
|
| |
|
| |
|
| |
|
| |
guest ::
