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Karyotype evolution of selected families of entelegyne spiders
Kotz, Matěj ; Král, Jiří (advisor) ; Nguyen, Petr (referee)
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...
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Evolution of karyotype, sex chromosomes and gene clusters in selected taxa of araneomorph spiders
Voráčková, Diana ; Forman, Martin (advisor) ; Sadílek, David (referee)
Spiders (Araneae) are a diverse group with various sex chromosome systems. The most common is X1X20 sex determination, X1X2 denotes two non-homologous X chromosomes and 0 the absence of Y. The presence of Y chromosome is rare among spiders and has been described mainly in Synspermiata, X1X2Y is probably ancestral constitution for this clade. The family Sicariidae was chosen to elucidate the evolution of sex chromosomes in Synspermiata. Karyotypes of 10 species whose 2n ranged from 19 to 23 were investigated in this study. The most common finding was X1X2Y in all studied Loxosceles species. The derived XY system was discovered in Sicarius. Furthermore, the distributional pattern of molecular cytogenetic markers (genes for 18S rRNA, 5S rRNA, histone H3 and U2 snRNA) was analysed using fluorescence in situ hybridization (FISH). These markers were found exclusively on autosomes, on one or two pairs. FISH with whole-genome probes of both sexes was performed to reveal distribution of Y specific sequences. Various patterns of Y differentiation were found in certain species. Y chromosome was small in all Sicariidae. A larger Y with a pronounced accumulation of Y-specific sequences has been detected in previous works - in the X1X2Y system of a synspermiate Pholcus phalongoides (Pholcidae). Pilot...
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Analysis of gonosomal mosaic using FISH method
ŠUTKOVÁ, Jana
In my bachelor thesis I dealt with the analysis of gonosomal mosaics. Mosaicism can be described as a condition in which two or more distinct cell lines originating from a single zygote are found in one organism. In women, the most common mosaic forms are Turner syndrome and triple X syndrome or superfemale. In the male population, Klinefelter syndrome and XYY syndrome (supermale) are most commonly detected. Mosaicism can be investigated by fluorescence in situ hybridization. In the theoretical part of my bachelor's thesis I focused on congenital chromosomal mosaicism, especially on its variants such as Klinefelter syndrome, Turner syndrome, triple X and XYY syndrome. Furthermore, in this part I dealt with fluorescence in situ hybridization. I described fluorescence per se and then its application in clinical practice, where several types of fluorescence in situ hybridization are used. In the practical part I examined the number of gonosomal chromosomes using fluorescence in situ hybridization. I prepared this part in the laboratory of the Faculty of Health and Social Sciences of the University of South Bohemia in České Budějovice. I examined 40 anonymized samples from 20 probands. Capillary blood samples and buccal swabs were taken from each of them. After hybridization of samples with centromeric probe for X and Y chromosomes microscopy was performed. In the last part of this bachelor thesis I dealt with the processing of the results obtained by fluorescence microscopy. Thus, a total of 6 cases of mosaicism were detected in women (the percentage of mosaic cells was above the admissible limit). In males there were a total of 2 cases of increased percentage of mosaic cells.
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Evolution of visual sensory system in the common barbel (Barbus barbus)
Konvičková, Zuzana ; Musilová, Zuzana (advisor) ; Pergner, Jiří (referee)
Vertebrates inherited five visual opsin classes from their common ancestor expressed in the rod and cone cells. While many vertebrate groups reduced the number of visual pigments they possess, opsins of teleost fishes have diversified. Today, teleosts outstand among all vertebrates in the number of visual pigments and photoreceptor types. This extraordinary development was also facilitated by the teleost- specific whole genome duplication that occurred approximately 350 Mya. Here I explored teleost species that recently underwent subsequent whole genome duplication - the common barbel (Barbus barbus). This event was accompanied by hybridization (i.e., it was allopolyploidization) and resulted in 14 opsin genes found in the genome, an unusually high number even among teleosts. In this thesis, I studied the effects of such an expanded opsin repertoire on the visual abilities of the common barbel. Based on the whole genome, I have completed the reference sequences of all opsin genes and revealed their positions on the chromosomes. I analysed retinal transcriptomes and constructed developmental series of opsin expression profiles. All opsin genes were preserved functional in the genome, even though one of them (green-sensitive, named RH2-4 in this thesis) was not found in the transcriptome and showed...
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Molecular genetic approaches used in preimplantation genetic analysis of human embryos in assisted reproduction
Limbergová, Jana ; Machoň, Ondřej (advisor) ; Šimoník, Ondřej (referee)
Preimplantation genetic testing is one of the main clinical procedures that take place in assisted reproduction centres around the world. It is sought after by couples for many different reasons. The causes of problems may relate to hereditary diseases that potential parents do not wish to pass on to their offspring, or may include the risk of transmission of chromosomal alterations. In addition, infertility may be caused by an increased risk of embryo aneuploidy, which correlates with mother's increased age and other factors that this bachelor thesis discusses. The bachelor thesis also focuses on up-to-date approaches to cytogenetic examinations for reproductive genetics and discusses recent clinical molecular methods that are used to improve the diagnosis and therapy of infertile couples. These are, for example, microarray methods, quantitative real-time PCR or next-generation sequencing and methods of whole-genome amplification. This work also summarizes methods that are gradually being abandoned, e.g. fluorescent in situ hybridization, and compares their advantages and disadvantages. Key words: preimplantation genetic testing, aneuploidy, structural rearrangements, monogenic diseases, biopsy, fluorescent in situ hybridization, microarray methods, comparative genomic hybridization, quantitative...
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Karyotype evolution of African clades of theraphosid mygalomorphs
Košátko, Prokop ; Král, Jiří (advisor) ; Nguyen, Petr (referee)
Karyotypes of mygalomorph spiders are not satisfactorily known. This thesis is focused on the basic cytogenetic analysis of selected species of African clades of theraphosid mygalomorphs. It includes four subfamilies: Eumenophorinae, Harpactirinae, Ischnocolinae and Stromatopelminae. Diploid numbers, chromosome morphology, sex chromosome systems and chromosome behaviour in male germline in the selected species of African theraphosid subfamilies were studied. The findings support published results, that refer of high karyotype diversity in Theraphosidae. Diploid chromosome number reduction is probably a basic trend of theraphosid karyotype evolution. The majority of analysed species exhibited one, two or three sex chromosomes. In some species neo-sex chromosome systems were found. In some species one or two sex chromosome pairs (SCP), composed of chromosomes which lack morphological differentiation were detected. Nucleolus organizer regions were detected by fluorescent in situ hybridization in several species. Constitutive heterochromatin detection was performed by C-banding in two species. Keywords: constitutive heterochromatin, diploid number, karyotype, fluorescence in situ hybridization, Mygalomorphae, nucleolus organizer region, SCP, sex chromosome, spider, Theraphosidae
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Analysis of chromosomal aberrations in sperm by fluorescence in situ hybridization
Bendová, Petra ; Diblík, Jan (advisor) ; Novotná, Drahuše (referee)
The presented bachelor work is focused on the determination of frequency chromosomally abnormal sperm in the semen of healthy men (donors) with normal karyotype (46, XY). The important process, which plays an irreplaceable role in the development of numerical aberrations of chromosomes or structural abnormalities in the segregation of the gametes, is meiosis. Therefore, I devote much attention on meiosis in the theoretical part. The theoretical part is focused on the process of pre mature sperm (spermatogenesis), and the consequences of fertilize the oocyte by aneuploid sperm. In my work I present an overview of numerical abnormalities in autosomes and gonosomes and their frequency and distribution of gametes in healthy men. I also focused on the distribution and a brief description of structural aberrations affecting chromosomes and not least I paid attention on method of multicolor interphase fluorescence in situ hybridization, which in combination with sperm chromatin dekondenzation become irreplaceable and valuable research tool for rapid analysis of chromosomal abnormalities in large sperm samples. The experimental part of bachelor work deals with monitoring the frequency of selected numerical abnormalities in sperm samples of five donors aged 23 to 30 years with the use of I-FISH (fluorescence in situ...
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Molecular-cytogenetic diagnostics of marker chromosomes
Tesner, Pavel ; Kočárek, Eduard (advisor) ; Zemanová, Zuzana (referee) ; Šubrt, Ivan (referee)
Supernumerary marker chromosomes (sSMCs) are a relatively rare cytogenetic phenomenon. Their laboratory examination is often difficult, and the clinical interpretation is even more challenging. The main reason is that most sSMC carriers have no clinical manifestations. The chromosome origin and exact range of the aberration are very important, as well as the fact that sSMCs are often found in mosaics that can strongly influence both the phenotype and the interpretation of result. Prenatal sSMC finding is one of the most challenging situations in both clinical and laboratory genetics. This work deals with the investigation process of sSMC carriers using molecular cytogenetic techniques, especially fluorescence in situ hybridization (FISH). We investigated a total of 67 families collected both prospectively and retrospectively, and we found 70 unique sSMCs in a total of 74 individuals. Six cases were familial and in three cases two sSMCs were found in one individual. According to the initial karyotype finding, the cases were divided into two groups, sSMCs supernumerary to a normal karyotype (group A) and sSMCT s supernumerary to the Turner karyotype (group B). The chromosomal origin was successfully determined in 88,6 % sSMCs. In group A the most common findings were sSMCs derived from chromosome 15,...
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Karyotype analysis of mesothelid spiders
Prokopcová, Lenka ; Král, Jiří (advisor) ; Zrzavá, Magda (referee)
Cytogenetics of mesothelid spiders is largely unkown. The presented diploma thesis is focused on the karyotype evolution of these spiders. As it is the most basal group of spiders, the analysis of its cytogenetics can bring important data about ancestral spider karyotype. In the framework of my thesis, I analysed diploid chromosome numbers, chromosome morphology, meiotic division, sex chromosomes and the pattern of selected molecular markers that were detected by fluorescence in situ hybridization. According to my results, mesothelid spiders have a high number of chromosomes and the prevalence of monoarmed chromosomes. Unlike other spiders, mesothelids have little differentiated sex chromosomes. Key words: evolution, spider, chromosome, karyotype, fluorescence in situ hybridization, nucleolar organiser region, sex chromosomes
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