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Morroll, Shaun Michael. "Mapping of yeast artificial chromosomes from Arabidopsis chromosome 5". Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.308922.
Pełny tekst źródłaDownie, Sarah Elizabeth. "Detection of chromosomes and chromosomal abnormalities in human sperm". Title page, contents and overview only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phd751.pdf.
Pełny tekst źródłaMorey, Céline. "Caractérisation du rôle de la région en aval du gène Xist lors de l'inactivation du chromosome X murin par mutagenèse ciblée dans les cellules ES". Paris 5, 2004. http://www.theses.fr/2004PA05N040.
Pełny tekst źródłaIn mammals, dosage compensation of X-linked genes is ensured by X-chromosome inactivation wherby one X chromosome in each female embryonic cell (ES) is chosen at random to become silenced. X-inactivation depends on the counting of X chromosomes and on the choice of the inactive X, It is mediated by the expression of the Xist non-coding RNA wich coats the inactive X and by the Tsix antisense transcipt, a Tsix antisense transcript, a Xist regulator. A 65 kb deletion extending 3' to Xist and including both Tsix and the DXPas34 minisatellite, disrupts choice and counting. Using a cre/loxP site-specific re-insertion strategy in XX deleted ES cells we showed that targeting back, at the 65 kb mutated locus, the Tsix antisense transcription fails to retore random X-inactivation. In contrast, normal counting can be restored in XO deleted ES cells. .
Landmann, Cedric. "Rôles et régulations de Polo et BubR1 sur les cassures double-‐brin de l'ADN en mitose". Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0852/document.
Pełny tekst źródłaThe presence of DNA double strand breaks (DSB) during mitosis is challenging for the cell, as it produces fragments of chromosome lacking a centromere. If not processed, this situation can cause genomic instability resulting in improper segregation of the broken fragments into daughter cells. We uncovered a mechanism by which broken chromosomes are faithfully transmitted to daughter cells via the tethering of the two broken chromosome ends. Several proteins including the mitotic kinase BubR1 and Polo are recruited to the breaks and mediate the proper segregation of the broken fragments. However, the mechanism underlying Polo and BubR1 recruitment to DNA breaks is unknown. Moreover, the molecular mechanisms by which Polo and BubR1 mediate the proper segregation of the broken fragments remain to be elucidated. We first investigated the role and regulation of BubR1 on DNA breaks during mitosis. We show that BubR1 requires Bub3 to localize on the broken chromosome fragment and to mediate its proper segregation. We also find that FizzyCdc20, a co--‐factor of the E3 ubiquitin ligase Anaphase--‐Promoting--‐Complex/Cyclosome (APC/C), accumulates on DNA breaks in a BubR1 KEN box--‐dependent manner. A biosensor for APC/C activity demonstrates a BubR1--‐dependent local inhibition of APC/C around the segregating broken chromosome. These results are consistent with a model where Bub3/BubR1 complex on DNA breaks functions to inhibit the APC/C locally via the sequestration of FizzyCdc20, thus preserving key substrates from degradation, which promotes proper transmission of broken chromosomes. In a second study, we investigated the dependency relationship between Polo and BubR1/Bub3/Fizzy on DNA breaks in mitosis. We used a pulsed UV laser to break one chromosome at a define time during mitosis. We immediately follow the recruitment of GFP--‐tagged proteins to laser--‐induced DNA breaks. My study reveals that Polo is promptly recruited to DNA breaks and precedes BubR1, Bub3 and Fizzy. In addition, while BubR1, Bub3 and Fizzy dissociation from the breaks coincide with telophase and the nuclear envelope reformation, Polo remains on the breaks well into interphase. We further show that the appearance of BubR1, Bub3 and Fizzy on DNA breaks is delayed in polo mutant, indicating that Polo is required for the robust and efficient recruitment of BubR1, Bub3 and Fizzy to DNA breaks. Finally, the timely accumulation of Polo, BubR1 and Bub3 to DNA breaks depends on two components of the DNA Damage Response, the MRN complex (Mre11--‐Rad50--‐Nbs1) and ATM (ataxia--‐telangiectasia mutated). This work gives us a better understanding on how Polo and BubR1, Bub3 and FizzyCdc20 are recruited to DNA breaks in mitosis and how they promote broken chromosomes segregation
Prades, Catherine. "Recherche de marqueurs polymorphes dans les régions centromériques des chromosomes humains". Montpellier 1, 1997. http://www.theses.fr/1997MON1T007.
Pełny tekst źródłaImakaev, Maksim (Maksim Viktorovich). "Polymer models of chromosomes". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/103234.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references (pages 203-215).
Studies of chromosomes have a long history. Since late XIX century, microscopy studies have revealed that chromosomal organization as seen by light microscopy is different among organisms, cell types, or stages of the cell cycle. However, the internal organization of chromosomes at scales below the diffraction limit largely remained unexplored. Recently, genomic techniques to measure contacts between genomic regions were developed; the most advanced of them, Hi-C, measures probabilities of contact between all pairs of genomic regions. Throughout my Ph.D, we have been developing methods to analyze Hi-C data, and to infer principles of chromosomal organization from the contact map provided by Hi-C. As a first step, we developed a toolset to map, analyze, and correct the Hi-C data. We then we performed polymer simulations that implement hypothetical principles of chromosomal organization and compared them to the Hi-C data. We showed that mitotic chromosomes in humans are not organized hierarchically, as thought previously, and are likely folded as an array of consecutive chromosomal loops. In the bacterium Caulobacter Crescentus, we showed that the chromosome is organized as a dense array of supercoiled plectonemes interspersed by highly transcribed regions free of plectonemes. Finally, for human interphase chromosomes, we showed that the equilibrium state of a long unknoted polymer chain is inconsistent with the observed properties of chromosomes.
by Maksim Imakaev.
Ph. D.
Mascarenhas, Judita. "Chromosome dynamics in Bacillus subtilis characterization of the structural maintenance of chromosomes (SMC) complex /". [S.l. : s.n.], 2004. http://archiv.ub.uni-marburg.de/diss/z2004/0125/.
Pełny tekst źródłaKulharya, Anita S. (Anita Singh). "Cytogenetics of chromosome 22 and its clinical relevance". Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc798385/.
Pełny tekst źródłaCoultas, Susan L. (Susan Lynette). "A comparison of straight-stained, Q-stained, and reverse flourescent-stained cell lines for detection of fragile sites on the human X chromosome". Thesis, North Texas State University, 1985. https://digital.library.unt.edu/ark:/67531/metadc798127/.
Pełny tekst źródłaKhalil, Ahmad M. "Histone modifications and chromatin dynamics of the mammalian inactive sex chromosomes title". [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0008329.
Pełny tekst źródłaTypescript. Title from title page of source document. Document formatted into pages; contains 102 pages. Includes Vita. Includes bibliographical references.
Novak, Ivana. "Molecular architecture of meiotic chromosomes /". Stockholm, 2006. http://diss.kib.ki.se/2006/91-7140-959-9/.
Pełny tekst źródłaTannier, Eric. "Evolution Combinatoire, Algorithmique des Chromosomes". Habilitation à diriger des recherches, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00750199.
Pełny tekst źródłaVásárhelyi, Krisztina. "Statistical study of human constitutional chromosome rearrangement breakpoint distributions". Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29201.
Pełny tekst źródłaMedicine, Faculty of
Medical Genetics, Department of
Graduate
He, Bin. "Mitotic Dynamics of Normally and Mis-attached Chromosomes and Post-mitotic Behavior of Missegregated Chromosomes". Diss., Virginia Tech, 2015. http://hdl.handle.net/10919/73495.
Pełny tekst źródłaPh. D.
Conia, Jérôme. "Analyse des chromosomes de plantes en cytométrie en flux : purification d'un chromosome de Petunia hybrida (Hort.)". Paris 11, 1988. http://www.theses.fr/1988PA112372.
Pełny tekst źródłaChan, David Yiu Leung. "Analysis of artificial chromosomes and factors affecting stability in murine and human cultured and embryonic stem cells". Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.568074.
Pełny tekst źródłaKaszás, Étienne. "Molecular and genetic analyses of the maize B chromosome centromere /". free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841157.
Pełny tekst źródłaMinnen, Anita [Verfasser], i Thorsten [Akademischer Betreuer] Mascher. "Structural Maintenance of Chromosomes (SMC) localization on the Bacillus subtilis chromosome / Anita Minnen. Betreuer: Thorsten Mascher". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2015. http://d-nb.info/1101344172/34.
Pełny tekst źródłaConia, Jérôme. "Analyse des chromosomes de plantes en cytométrie en flux purification du chromosome I de Petunia hybrida /". Grenoble 2 : ANRT, 1988. http://catalogue.bnf.fr/ark:/12148/cb37612978g.
Pełny tekst źródłaMajed, Zeina. "Elaboration d'un nouveau modèle pour la caractérisation de nouveaux gènes impliqués dans la stabilité des sites fragiles". Montpellier 1, 2009. http://www.theses.fr/2009MON1T022.
Pełny tekst źródłaCommon fragile sites are chomosomal regions involved in recurrent breaks, which are "expressed" under various physiological stresses, most of them are known to disturb DNA replication. A direct link between fragile sites and emergence of various types of chromosomal rearrangement has been established, even in early stages of tumorigenesis. However, only few genes involved in genome stability at fragile sites have been identified. The aim of this study is to identify new genes involved in the expression of fragile sites and to elucidate molecular processes that affect their stability. We established a cell based system on a mismatch repair deficient background. 20 candidate genes were targeted in this study. We examined the incidence of frameshift mutations in 32 mononucleotide repeats of these genes. 17 frameshift mutations were found. We demonstrate that frameshift mutations affecting coding mononucleotide repeat of ATR, inactivate one of the two alleles leading to formation of breaks at fragile sites. This collection of clones gives us a unique cellular model to study precisely the maintenance of genome stability at fragile sites. Furthermore, we have investigated the effects of the deregulation of the expression of MCPH1/BRIT1 on common fragile site stability. MCPH1/BRIT1 acts as a regulator of both the intra-S and G2/M keckpoints. We show that deregulation of the expression of MCPH1/BRIT1 increase H2AX phosphorylation suggesting the accumulation of DNA double-strand breaks. This leads to formation of breaks at fragile sites. These findings demonstrate a critical role for the MCPH1/BRIT1 in regulating chromosome stability, and in particular, common fragile site
Edwards, Frances. "Mécanismes d’alignement et de ségrégation des chromosomes lors de la mitose dans les zygotes de Caenorhabditis elegans". Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC110.
Pełny tekst źródłaMitosis is a process by which cells multiply, contributing to the generation of new unicellular organisms, or the construction of multicellular organisms. During mitosis, the daughter cells inherit an identical copy of the mother cell’s replicated genome. Errors in genetic material distribution can lead to aneuploidy, a hallmark of developmental diseases including cancer. The accurate segregation of sister chromatids relies on the mitotic spindle, a bipolar network of microtubules that governs chromosome movements by interacting with the kinetochores assembled on sister chromatids. This drives chromosome alignment at the spindle equator, and chromosome bi-orientation meaning that sister kinetochores are connected to opposite spindle poles, laying the ground for sister chromatid segregation during anaphase. Once segregation has initiated, the microtubule-based central spindle is assembled between the two sets of chromosomes. This structure contributes to sister chromatid segregation, by specifying the location and favoring the ingression of the cytokinesis furrow. During my thesis, I have studied the functions of a subset of conserved kinetochore proteins called BUB-1, HCP-1/2CENP-F and CLS-2CLASP, during mitosis in C. elegans zygotes. By combining genetics and live imaging, I have shown that these proteins are involved both in chromosome alignment and segregation. In particular, I have shown that BUB-1 contributes to chromosome alignment by accelerating the establishment of end-on kinetochore-microtubule attachments, while controlling the conformation and maturation of these attachments. These activities rely on BUB-1’s downstream partners HCP-1/2CENP-F and CLS-2CLASP, but also on the RZZ complex and dynein, as well as an activity for BUB-1 in inhibiting the recruitment of the SKA complex. Additionally, I have shown that BUB-1, HCP-1/2CENP-F and CLS-2CLASP contribute to central spindle microtubule assembly, via CLS-2CLASP’s polymerase activity. This function relies on the prior kinetochore recruitment of these proteins during metaphase by the kinetochore scaffold protein KNL-1, revealing a new function for the kinetochore in central spindle assembly. Together, this work identifies versatile functions for this subset of conserved kinetochore proteins, making them major safe-keepers of genomic integrity
Almagro, Sébastien. "Organisation structurale et fonctionnelle des chromosomes". Phd thesis, Université Joseph Fourier (Grenoble), 2003. http://tel.archives-ouvertes.fr/tel-00003099.
Pełny tekst źródłaLaval, S. H. "Molecular analysis of mammalian sex chromosomes". Thesis, University of Oxford, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302954.
Pełny tekst źródłaHeller, Raoul. "Engineering of human artificial mini-chromosomes". Thesis, University of Oxford, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360317.
Pełny tekst źródłaBarnett, Michael A. "Telomere directed breakage of mammalian chromosomes". Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314882.
Pełny tekst źródłaBellott, Daniel Winston. "Sequence of the chicken sex chromosomes". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/57992.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references.
In birds, as in mammals, the chromosome complement determines sex. Male birds are designated ZZ, female ZW. Mammals have the opposite system; males are XY and females XX. Both the avian ZW and mammalian XY pair are believed to have evolved from autosomes, with dramatic changes, both gene loss as well as gene acquisition and amplification occurring on the sex-specific W and Y chromosomes. In contrast, Z and X chromosomes are assumed to have diverged little from their autosomal progenitors. The Z and W sex chromosomes of the chicken provide a unique opportunity to study the evolution of sex chromosomes in a second lineage with an alternate system of heterogamety. We produced the finished sequence of the chicken Z chromosome and generated female-specific markers necessary to produce a complete sequence of the chicken W chromosome. Already our analysis of the Z chromosome has revealed that the sex chromosomes of birds evolved independently of the sex chromosomes of mammals. Despite this independence, the chicken Z chromosome converged on a suite of features analogous to those of the human X chromosome: low gene density, an enrichment for interspersed repeats, and large multi-copy gene families expressed in the testis. These features arose during the evolution of the Z and X chromosomes as sex chromosomes, overturning the notion that Z and X chromosomes are evolutionarily stable. Our preliminary efforts on the W chromosome have provided insights into its structure and underscore the ubiquity of gene acquisition and amplification on vertebrate sex chromosomes. As we accumulate genomic data from additional sex chromosomes, explaining the evolutionary forces that result in gene acquisition and amplification will remain a major challenge.
by Daniel Winston Bellott.
Ph.D.
QIU, XIAOHUI. "Vers la classification automatique des chromosomes". Nantes, 1990. http://www.theses.fr/1990NANT2062.
Pełny tekst źródłaTapia, Páez Isabel. "Characterization of human chromosome 22 : cloning of breakpoints of the constitutional translocation t(11;22)(q23;q11) and detection of small constitutional deletions by microarray CGH /". Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-505-0.
Pełny tekst źródłaLindow, Janet C. (Janet Christine) 1974. "A role for the Bacillus subtilis Structural Maintenance of Chromosomes (BsSMC) protein in chromosome organization and compaction". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8385.
Pełny tekst źródłaIncludes bibliographical references.
All cells must compact their chromosomes in order for the DNA to fit inside the cell or nucleus. In Bacillus subtilis, and other bacteria, replication occurs simultaneously with the organization, compaction and segregation of newly duplicated chromosomal regions. My work indicates that the B. subtilis Structural Maintenance of Chromosomes (BsSMC) protein is involved in compacting and organizing the chromosome. Increasing the amount of supercoiling of DNA is a means to compact the chromosome. This thesis describes a role for BsSMC in supercoiling. I determined that BsSMC can alter the DNA topology of plasmids in vivo. There is also genetic evidence that BsSMC is involved in supercoiling. An smc null mutant is hypersensitive to inhibitors of DNA gyrase, which reduce the level of negative supercoiling in the cell. Conversely, depletion of Topoisomerase I, which increases the amount of negative supercoiling of the chromosome, partially suppresses the phenotype of an smc null mutant. These data are consistent with the model that BsSMC affects chromosome compaction by constraining positive supercoils. Interestingly, SMC-containing complexes in eukaryotes are able to constrain positive supercoils in vitro and affect chromosome architecture suggesting that there is a conserved function for SMC proteins in chromosome structure. I also determined the subcellular localization of BsSMC. I found that BsSMC is a moderately abundant protein that can bind to many regions of the chromosome. A portion of BsSMC localizes in a pattern similar to the replication machinery.
(cont.) Simultaneous localization of BsSMC and a component of the replisome revealed that they are usually in the same region of the cell but are not always colocalized. Finally, the formation of BsSMC foci is dependent on the presence of the nucleoid but not ongoing replication. I propose that BsSMC is acting to compact newly replicated DNA by affecting DNA topology and is thereby facilitating the partitioning of sister chromosomes to opposite halves of the cell.
by Janet C. Lindow.
Ph.D.
ROTOMONDO, FRANCOISE. "Caracterisation de la region pericentromerique du chromosome 19 murin, a l'aide de chromosomes artificiels de levures (yacs)". Nice, 1996. http://www.theses.fr/1996NICE5012.
Pełny tekst źródłaSzabo, Quentin. "Étude du repliement tridimensionnel de la chromatine en domaines topologiques". Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTT064.
Pełny tekst źródłaMy thesis project consisted in studying the mechanisms of the three-dimensional genome folding in eukaryotic cells. The organization of chromosomes is closely related to the regulation of many biological processes, such as gene expression control, DNA replication or genomic stability. The Hi-C "chromosome conformation capture" method, which allows the mapping of interactions between DNA regions, has revealed that the genome of many species is organized into domains enriched in chromatin interactions, the "Topologically Associating Domains" (TADs). TADs have emerged as major players of genome regulation by their ability to spatially define functional domains. However, chromosome conformation capture methods generate averaged interaction profiles that generally come from an ensemble of cells. Determining the nature and the folding of TADs in individual cells is therefore crucial to better understand the structure-function relationship of these domains. During my thesis, I used a combination of fluorescent DNA labeling and super-resolution microscopy to characterize the organization of chromosomes in single cells. In Drosophila, TADs coincide with the partitioning of the chromatin into distinct epigenetic domains. In this species, we could characterize the folding of the chromosomes into a series of discrete units that correspond to TADs, reflecting the mutual exclusion of transcriptionally active and inactive regions. These results indicate that Drosophila TADs form physical domains that characterize a higher-order layer of chromosome folding in individual cells. In mammals, the majority of TADs emerge through the action of the cohesin complex and the CCCTC-binding factor (CTCF) bound at their borders. The application of super-resolution imaging in mouse embryonic stem cells and neuronal progenitor cells revealed the high degree of cell-to-cell heterogeneity of TAD folding, ranging from condensed and globular objects to dispersed and stretched conformations. We were able to observe their organization into discrete subdomains which seem to represent a general property of the folding of the chromatin fiber at the nanoscale. Furthermore, our data indicate that the physical intermingling of the chromatin is highly favored within TADs in a large majority of cells. Depletion of CTCF abolishes the TAD-dependent spatial organization of the chromatin fiber, highlighting the role of this protein in generating physical barriers between adjacent TADs. Altogether, our results demonstrate that the dynamic folding of TAD is compatible with the establishment of chromosomal environments in which contacts are privileged, and thus reconcile the probabilistic nature of chromatin folding with the proposed role of TADs in the spatial definition of functional genomic units
Muir, Kyle. "Caractérisation biochimique et biophysique du complexe cohésine". Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAV005/document.
Pełny tekst źródłaSister chromatid cohesion is a fundamental prerequisite to faithful genome segregation. Cohesion is precisely regulated by accessory factors that modulate the stability with which the cohesin complex embraces chromosomes. One of these factors, Pds5, engages cohesin through Scc1 and participates both in the enhancement of cohesion, and conversely in mediating the release of cohesin from chromatin. In this thesis the crystal structure of a complex between budding yeast Pds5 and Scc1 is presented, thus elucidating the molecular basis of Pds5 function. Pds5 forms an elongated HEAT repeat that binds to Scc1 via a conserved surface patch. Through complementary cell biological and biochemical characterisation of this structure, the thesis demonstrates that the integrity of the Pds5–Scc1 interface is indispensable for the recruitment of Pds5 to cohesin, and that its abrogation results in loss of sister chromatid cohesion and cell viability. The results presented in this thesis therefore suggest that Pds5 is a constitutively bound, core subunit of cohesin
Bhatt, Samarth. "Segregation analysis of paracentric inversions in human sperm". Montpellier 1, 2008. http://www.theses.fr/2008MON1T002.
Pełny tekst źródłaTomaszkiewicz, Marta. "Molecular characterization of the Y chromosome-linked sex-determining region of the platyfish Xiphophorus maculatus". Thesis, Lyon, École normale supérieure, 2012. http://www.theses.fr/2012ENSL0791.
Pełny tekst źródłaThe molecular and evolutionary basis of sex determination in vertebrates needs to be unveiled via comparison of different systems. Fish exhibit hypervariability of sex determination mechanisms. Thanks to the analysis of the Bacterial Artificial Chromosome (BAC) library covering the sex chromosomes of the platyfish Xiphophorus maculatus (Rio Jamapa population, XX /XY), three copies of a new gene have been identified in the sex-determining region of the Y but not the X chromosome, and named teximY. Four autosomal counterparts of teximY have been also detected in the genome of the platyfish with one of them, texim1 presenting 95% of cDNA sequence identity with the Y-linked copies. RT-qPCR expression analyses have been performed for each copy in male and female tissues. Two Y-linked teximY copies were preferentially expressed in testis, whereas the autosomal copy texim1 showed preferential expression in male and female gonads. In situ hybridizations with a teximY/1 probe revealed expression in late spermatids and spermatozeugmata. Texim sequences were detected in several fish species, but not in zebrafish, as well as in cephalochordates, urochordates and sea echinoderms but not in tetrapods. Predicted Texim proteins are related to proteins from different origins. Interestingly, texim genes are associated with a Helitron transposon in fish but neither in cephalochordates nor in echinoderms, suggesting capture and mobilization of an ancestral texim gene at the base of the bony fish lineage. TeximY proteins may play a role in Helitron transposition in the male germ line in fish, or texim genes are spermatogenesis genes mobilized and spread by transposable elements in fish genomes
Sousa, dos Santos Aretuza. "Molecular cytogenetics and phylogenetic modeling to study chromosome evolution in the araceae and sex chromosomes in the cucurbitaceae". Diss., Ludwig-Maximilians-Universität München, 2014. http://nbn-resolving.de/urn:nbn:de:bvb:19-174017.
Pełny tekst źródłaSundström, Hannah. "Mutation and Diversity in Avian Sex Chromosomes". Doctoral thesis, Uppsala University, Department of Evolutionary Biology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3732.
Pełny tekst źródłaSex chromosomes are useful for the study of how factors such as mutation, selection, recombination and effective population size affect diversity and divergence.
A comparison of gametologous introns in seven different bird species revealed a complete lack of diversity on the female-specific W chromosome. In contrast, Z had at least one segregating site in all examined species. This can be explained by the lower mutation rate and lower effective population size of W but also suggests that selection affects diversity levels on the non-recombining W chromosome.
In a diverse set of chicken breeds, the Z chromosome showed reduced diversity compared to autosomes and significant heterogeneity in levels of variation. High variance in male reproductive success, leading to a reduced Z chromosome effective population size, can partly explain this observation. In addition, we suggest that selective sweeps frequently act on the Z chromosome and are responsible for a significant part of the observed Z reduction.
Differences in the mutation rate of Z and W chromosome sequences indicate that the time spent in male germ line is important for the mutation rate, but does not exclude a specifically reduced mutation rate on the Z chromosome. Estimates of mutation rate in autosomal, Z- and W-linked chicken and turkey sequences indicate a slight reduction in the rate on Z. However, due to rate heterogeneity among introns this reduction is not significant and we cannot exclude male biased mutation as the single cause of rate variation between the chromosomal classes.
Analysis of indel mutation rates in avian and mammalian gametologous introns show frequent occurrence of indels on both W and Y, excluding meiotic recombination as the only source of this type of mutation. The different indel rate patterns in birds (Z>W) and mammals (X=Y) suggest that indels are caused by both replication and recombination.
Sundström, Hannah. "Mutation and diversity in avian sex chromosomes /". Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3732.
Pełny tekst źródłaRoss, Mark T. "Molecular studies of the human sex-chromosomes". Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.258353.
Pełny tekst źródłaHarrison, Peter William. "Bacterial chromids are neither chromosomes nor plasmids". Thesis, University of York, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.556257.
Pełny tekst źródłaSun, Lawrence (Lawrence J. ). "Inference of 3D structure of diploid chromosomes". Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119570.
Pełny tekst źródłaThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 61-62).
The spatial organization of DNA in the cell nucleus plays an important role for gene regulation, DNA replication, and genomic integrity. Through the development of chromosome capture experiments (such as 3C, 4C, Hi-C) it is now possible to obtain the contact frequencies of the DNA at the whole-genome level. In this thesis, we study the problem of reconstructing the 3D organization of the genome from whole-genome contact frequencies. A standard approach is to transform the contact frequencies into noisy distance measurements and then apply semidefinite programming (SDP) formulations to obtain the 3D configurations. However, neglected in such reconstructions is the fact that most eukaryotes including humans are diploid and therefore contain two (from the available data) indistinguishable copies of each genomic locus. Due to this, the standard approach performs very poorly on diploid organisms. We prove that the 3D organization of the DNA is not identifiable from exclusively chromosome capture data for diploid organisms. In fact, there are infinitely many solutions even in the noise-free setting. We then discuss various additional biologically relevant constraints (including distances between neighboring genomic loci and to the nucleus center or higher-order interactions). Under these conditions we prove there are finitely many solutions and conjecture we in fact have identifiability. Finally, we provide SDP formulations for computing the 3D embedding of the DNA with these additional constraints and show that we can recover the true 3D embedding with high accuracy even under noise.
by Lawrence Sun.
M. Eng.
BOURSAUX, EUDE CAROLINE. "Chromosomes plastiques et lineaires chez les spirochetes". Paris 6, 1996. http://www.theses.fr/1996PA066496.
Pełny tekst źródłaBARIL, CELINE. "Chromosomes circulaires et lineaires chez les spirochetes". Paris 7, 1991. http://www.theses.fr/1991PA077131.
Pełny tekst źródłaLee, Shane. "Genetic algorithms, orthognal arrays and diploid chromosomes". Thesis, University of Wales, Newport, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.761244.
Pełny tekst źródłaDonald, Tamzin. "Organisation and expression of plant B chromosomes /". Title page, table of contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phd6758.pdf.
Pełny tekst źródłaNISKA, JOANNA. "TERMINATING REPLICATION AT TERS AT EUKARYOTIC CHROMOSOMES". Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/234148.
Pełny tekst źródłaMercy, Guillaume. "L'organisation 3D des chromosomes synthétiques de levure". Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS034/document.
Pełny tekst źródłaThe international project Sc2.0 started 10 years ago by the Pr. Jef Boeke aims to build a fully synthetic genome of S. cerevisiae which increases the genome stability by removing all repeated sequences (tRNA, transposable elements, etc.), and implements SCRaMbLE (for Synthetic Chromosome Rearrangement and Modification by LoxP-mediated Evolution), an inducible, high-throughput chromosome rearrangement system. This design is highly conservative with respect to gene content, the deletion of several classes of repeated sequences and the introduction of thousands of designer changes. However, it may affect genome organization and potentially alter cellular functions. To determine wether those modifications affected the three-dimensional conformation of synthetic chromosmes, we investigated it using chromosomes conformation capture coupled to second generation sequencing method (Hi-C). Currently, eight synthetic chromosomes (synI, synII, synIII, synV, synVI, synIX-R, synX et synXII) have been fully assembled. Using these strains we observed that the large-scale genomic organization is globally unaffected by the presence of synthetic chromosome(s). Two exceptions are synIII, which lacks the silent mating-type cassettes, and synXII, specifically when the ribosomal DNA is moved to another chromosome. We also exploited the contact maps to detect rearrangements induced in these SCRaMbLE strains
Mercy, Guillaume. "L'organisation 3D des chromosomes synthétiques de levure". Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS034.pdf.
Pełny tekst źródłaThe international project Sc2.0 started 10 years ago by the Pr. Jef Boeke aims to build a fully synthetic genome of S. cerevisiae which increases the genome stability by removing all repeated sequences (tRNA, transposable elements, etc.), and implements SCRaMbLE (for Synthetic Chromosome Rearrangement and Modification by LoxP-mediated Evolution), an inducible, high-throughput chromosome rearrangement system. This design is highly conservative with respect to gene content, the deletion of several classes of repeated sequences and the introduction of thousands of designer changes. However, it may affect genome organization and potentially alter cellular functions. To determine wether those modifications affected the three-dimensional conformation of synthetic chromosmes, we investigated it using chromosomes conformation capture coupled to second generation sequencing method (Hi-C). Currently, eight synthetic chromosomes (synI, synII, synIII, synV, synVI, synIX-R, synX et synXII) have been fully assembled. Using these strains we observed that the large-scale genomic organization is globally unaffected by the presence of synthetic chromosome(s). Two exceptions are synIII, which lacks the silent mating-type cassettes, and synXII, specifically when the ribosomal DNA is moved to another chromosome. We also exploited the contact maps to detect rearrangements induced in these SCRaMbLE strains
Martins, Francisco de Lemos. "Decrypting the Vibrio cholerae crtS site and its role on the coordinated replication of the two chromosomes". Electronic Thesis or Diss., Sorbonne université, 2018. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2018SORUS126.pdf.
Pełny tekst źródłaBacterial genomes are mainly composed of two types of replicons: chromosomes, which are essential, and plasmids. Although most bacteria have only one chromosome, bacteria with secondary chromosomes have arisen independently in several taxa and represent approximately 10% of all bacterial species. Secondary chromosomes originate from plasmids and possess plasmid-type replication systems. While chromosomes replicate once and during a defined period of the cell cycle, plasmids generally replicate randomly. Vibrio cholerae has its genome divided in two chromosomes (Chr1 and Chr2) that use distinct initiators for replication. Chr1 replication depends on the ubiquitous initiator DnaA, while Chr2 replication is initiated by a Vibrio specific factor, RctB. Despite its plasmid origins, Chr2 replication is tightly controlled and occurs once per cell cycle. Both chromosomes communicate with each other to coordinate their replication through an RctB-binding locus on Chr1, called crtS. We have shown that crtS replication is crucial to trigger Chr2 replication initiation. However, the molecular mechanism by which crtS controls the initiation of Chr2 replication was still obscure. Here we combined in vivo and in vitro approaches to shed light on this question. We have shown that crtS activity is driven by RctB binding in a methylation-independent manner. This appears to be an effective way to integrate the Chr2 replication in the cell cycle
Kayserili, Melek A., Dave T. Gerrard, Pavel Tomancak i Alex T. Kalinka. "An Excess of Gene Expression Divergence on the X Chromosome in Drosophila Embryos: Implications for the Faster-X Hypothesis". Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-180730.
Pełny tekst źródłaStear, Jeffrey Hamilton. "Studies of chromosome structure and movement in C. elegans /". Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/5056.
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