National Repository of Grey Literature 4 records found  Search took 0.00 seconds. 
Genomic approach in speciation studies
Habalová, Kateřina ; Hulva, Pavel (advisor) ; Mikulíček, Peter (referee)
Speciation, adaptation and hybridization are three concepts, each one referring to different process but having a common evolutionary context. Maternal line splits into two sister lines or only one line cleaves from maternal one during speciation. However it leads to formation of new species. Adaptation and hybridization can lead to formation of new species as well. New species arise by adapting to new conditions during adaptation. Within hybridization it is a desecendant of two different lines mating amongst themselves. Most of this thesis is being addressed to these issues, the lesser part is addressed to specific examples. The chapter about next-generation sequencing methods is also included, as these methods have been used more frequently recently. Key words: speciation, adaptation, hybridization, genomics, next-generation sequencing
Phenotypic and molecular approaches in the systematics of the Palearctic and Neotropic tree frogs, Hyla and Osteocephalus (Amphibia: Hylidae)
Gvoždík, Václav ; Moravec, Jiří (advisor) ; Mikulíček, Peter (referee) ; Hulva, Pavel (referee)
The systematics and taxonomy of tree frogs of the family Hylidae has undergone turbulent changes both at higher (subfamilies, genera) and lower (species) level during the last decades. The original approach used morphological characters to distinguish tree frogs. It has been completed by bioacoustics, since the advertisement calls of the males were in some cases found to represent an important behavioural reproductive barrier and therefore useful for systematic evaluations. However, a completely new impulse was given to systematics by the introduction of modern genetic methods. These methods have allowed to distinguish not only morphologically but even acoustically cryptic taxa. The most reliable method to distinguish tree frogs at present is a combination of data from the different disciplines. The present dissertation thesis aims to evaluate the systematics of tree frogs of the genus Hyla from Eastern Europe and the Middle East as well as the systematics of the Amazonian genus Osteocephalus using a combination of morphological, bioacoustic and molecular approaches. The thesis is composed of a general introduction, three published papers, two manuscripts under reviews and a conclusion chapter. The first three papers deal with the phenotypic (morphological plus bioacustic) approach in systematic...
Lost sex: multilocus DNA evolution the hybrid fish complex C.taenia (Teleostei)
Choleva, Lukáš ; Janko, Karel (advisor) ; Mikulíček, Peter (referee) ; Hulva, Pavel (referee)
12 General summary "It is unwise to intrude the suggestion of parthenogenesis, even of a modified sort, into vertebrate literatures. The phenomenon is so at variance with what is known and beleived about vertebrates development that I am sure no vertebrate morphologists would admit for a moment that the natural development from egg to sexual maturity of an individual vertebrate without the direct inclusion of the male element is within the realm of probability", reacted the morphologist Howell (1933. Science 77: 389-390) sarcastically on the discovery of the first recognized asexual vertebrate, a live-bearing fish Poecilia formosa (Hubbs et Hubbs 1932. Science 30: 628-630). "The examples of parthenogenesis has been reported in almost all vertebrate groups," (Lampert 2008. Sexual Development 2: 290-301). The ongoing effort to explain the widespread occurrence of sexual reproduction among animals is often called the "queen of problems in evolutionary biology", and there is still no consensus regarding the explanation. Simultaneously, asexual reproduction exists among some animals. Here, the 'asexuality' refers to any reproductive process that does not involve sex (Mendelian meiosis is mising), except self-fertilization. One individuum produces a progeny genetically identical to its parent, except those sites...
Earlier evolutionary dead-ends, now the creators of a reproductive strategy: the origin and reproduction of the all-male water frog lineage Pelophylax esculentus
Doležálková, Marie ; Choleva, Lukáš (advisor) ; Mikulíček, Peter (referee) ; Kratochvíl, Lukáš (referee)
Asexual modes of reproduction are usually based on the principle of copying (cloning) DNA from the female and passing it on to the offspring. For most asexually reproducing vertebrates the progeny develop from an unreduced and often unfertilised egg. This is driven by the mechanisms of parthenogenetic and gynogenetic reproduction. While in the former the clonal germ cell develops spontaneously and separately, in the latter a sexual partner is needed to activate the cleavage of the ovum, although without the fusion of the sperm and egg. Therefore in both cases there is no fertilization and the clonal progeny consist solely of daughters, hence the majority of previous studies have only focused on asexual female lineages. However, on rare occasions asexual clonal males can arise when the right fertilization occurs. Whilst these offspring are usually infertile, fertile diploid asexual males have been discovered in just three genera of hybrid origin in vertebrates. One of these unique cases is the European water frog complex of the genus Pelophylax, whose distribution includes the Czech Republic. In areas around the upper Odra River populations of hybrid males were recently discovered who form stable all-male lineages, similar to those formed by asexual females. The results of this study show that males produce...

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