Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 18 of 18 for “"Gene evolution"”.
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Investigating R gene evolution by meiotic recombination using synthetic gene clusters in Arabidopsis
Plant gene families organized as linked clusters are capable of evolving by a process of unequal crossing-over. This results in the formation of chimeric genes that may impart a novel function. However, the frequency and functional consequences of these unequal cross-over events are poorly …
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SELECTIVE FORCES SHAPING DUPLICATE GENE EVOLUTION: INSIGHTS FROM STOCHASTIC MODELING AND PATTERNS OF RETENTION
… can provide clues to understand the process of evolution. Overall, this helps us understand the history of life and how organisms have fundamentally changed and adapted to their environments. Gene duplication is an important mechanism for molecular evolution because it provides opportunity for …
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Using Synthetic Gene Clusters to Model Resistance Gene Evolution by Meiotic Recombination in Arabidopsis thaliana
… of constitutively expressed resistance (R) genes. R genes recognize pathogen gene products as signals of invasion. We are interested in how plants evolve R genes to keep pace with rapidly evolving pathogen populations. The mechanisms that drive the evolution of new R genes are poorly …
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The chromatin landscape of barley: gene expression, evolution and epigenetics
… a half of the barley genome and a fifth of the genes are constrained within a low-recombining pericentromeric (LR-PC) region. I explored the LR-PC gene component with a genomic investigation of gene expression, diversity and evolution. Chromatin environments were also explored in the LR and high …
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Bayesian Inference of Phylogenetic Networks
… (MSC) is a statistical framework that models how gene genealogies grow within the branches of a species tree. The field of computational phylogenetics has witnessed an explosion in the development of methods for species tree inference under the MSC, owing mainly to the accumulating evidence of …
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A survey of fly and nematode small RNAs by deep sequencing
… hairpin, then Dicer cleaves near the loop to generate a miRNA:miRNA* duplex. Large-scale sequencing of cDNAs derived from endogenously expressed small RNAs is used here to examine the small RNAs of the nematode Caenorhabditis elegans and the fly Drosophila melanogaster, revealing a number of …
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Partial structural characterization of the cytoplasmic hemoglobin of Nostoc commune UTEX 584 expressed in Escherichia coli
… in cyanobacterium Nostoc commune revealed a gene encoding for a hemoprotein, known as cyanoglobin. The cyanoglobin gene was isolated and subcloned into Escherichia coli previously. The study presented here encompasses the optimization of growth conditions for the transformed F. coli, with …
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Quantifying evolution and natural selection in vertebrate noncoding sequence
When studying genomic evolution, biologists find it important to identify varying patterns of natural selection. Many traditional methods of classifying directional selection have relied on models that categorize mutations as function-altering or neutral, and then comparing the rates of the two …
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Studies on the Modular Evolution of Genes
Gene evolution is primarily studied through the observations of comparative cumulative point mutations between homologs. Genes also evolve through “remodelling”, the process of repurposing and reorganising genes and gene fragments into novel sequences. Gene remodelling is a relatively …
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Evolution and functional specializations in nocturnal environments: insights from visual pigments in Chiroptera
… an ideal model to investigate how diverse evolutionary pressures shaped sensory adaptation. At the molecular level, vision is initiated through activation of visual pigments, light-sensitive complexes expressed in photoreceptor cells in the retina that have been shown to evolve in response …
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Complex evolution of mitochondrial genomes: lessons from salamanders
This dissertation research on genome evolution focuses on understanding the mechanisms that drive the evolution of mitochondrial genome size, content, and organization in animals. This research uses a combination of empirical and computational approaches to examine the evolution of mitochondrial …
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The early zygotic genes and microRNAs in the yellow fever mosquito Aedes aegypti and the Asian malaria mosquito Anopheles stephensi
… yellow fever and dengue fever. To manipulate gene expression in mosquito and spread desired genes among natural population for vector control, a thorough understanding of mosquito development and gene regulation is critical. Early embryogenesis is a rapid, complex yet crucial process in the …
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Computational Insights into Evolutionary Dynamics of Human and Primate Genes
The evolutionary history of genes across different species is a subject of research interest. For human genes, there is a particular focus on investigating the possible origins of genes. However, there has been limited research on the development process from an evolutionary perspective. …
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The Molecular Evolution of the Serotonin System in Macaques (MACACA): a Detailed Survey of Four Serotonin-Related Genes
… to behavior, and little is known about its evolution. This is unfortunate, since the serotonin system has great potential to inform our understanding of behavioral evolution. I seek to address this gap in knowledge by investigating the molecular evolution of the serotonin system in macaques …
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Phylogeny Inference in the Presence of Incomplete Lineage Sorting, Gene Duplication and Loss and Hybridization
… their most recent common ancestral species. A gene tree captures the evolutionary history of an individual gene or, more generally, non-recombining genomic region. A very complex relationship exists between the phylogeny of a set of species and the trees of genes in the genomes of those …
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Creating sense from non-sense DNA: de novo genesis and evolutionary history of antifreeze glycoprotein gene in northern cod fishes (gadidae)
… the fish. How and from where this important new genetic trait evolved in the gadid genome remained unknown, as thus far there are no homologous sequences in databases to infer genetic ancestry based on sequence homology. Additionally, the seven AFGP-bearing species are dispersed in separate …
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THE ROLE OF COMPLEX EVOLUTIONARY DYNAMICS IN MOLECULAR SEQUENCE ANALYSIS
… events (MH) on the statistical inference of evolutionary rate parameters. In evolutionary terms, MH events represent rare phenomena which may have strong effects on protein-coding genes. Evidence for MH events directly impact the patterns and processes of protein-coding gene evolution across …
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Investigating the evolution and function of Wnt ligands
Wnt genes encode secreted glycoproteins which play an important role in development of all animals. Overall, thirteen subfamilies of Wnt ligands are present and all of them can already be found in the most basal metazoans. The importance of this large gene family and its evolutionary conservation …