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Mitochondrial Genome Structure And Double Strand Break Repair In Arabidopsis Thaliana, Sterling Ericsson
Mitochondrial Genome Structure And Double Strand Break Repair In Arabidopsis Thaliana, Sterling Ericsson
School of Biological Sciences: Dissertations, Theses, and Student Research
The mitochondrial genomes of plants are known for their variability in size and arrangement, yet low mutation rates in coding sequences. These opposing characteristics have been suggested to be due to the stability of their DNA maintenance processes and the usage of a double strand break repair (DSBR) system. The components of this repair complex remain poorly understood and only a few of the involved enzymes have been identified, making direct analysis difficult. The flowering plant species Arabidopsis thaliana has been used as a model organism for genome modification and subsequent phenotypic and genotypic impacts. The aims of this research …
Plant Mitochondrial Genome Evolution And Structure Has Been Shaped By Double-Strand Break Repair And Recombination, Emily Wynn
School of Biological Sciences: Dissertations, Theses, and Student Research
Plant mitochondrial genomes are large but contain a small number of genes. These genes have very low mutation rates, but genomes rearrange and expand at significant rates. We propose that much of the apparent complexity of plant mitochondrial genomes can be explained by the interactions of double-strand break repair, recombination, and selection. One possible explanation for the disparity between the low mutation rates of genes and the high divergence of non-genes is that synonymous mutations in genes are not truly neutral. In some species, rps14 has been duplicated in the nucleus, allowing the mitochondrial copy to become a pseudogene. By …
The Mechanism Of Small Rna Biogenesis, Degradation, And Function In Arabidopsis, Meng Xie
The Mechanism Of Small Rna Biogenesis, Degradation, And Function In Arabidopsis, Meng Xie
School of Biological Sciences: Dissertations, Theses, and Student Research
Eukaryotic small RNAs play important roles in many biological processes through sequence-specific RNA silencing. In plants, there are mainly two small RNAs triggering gene silencing: microRNAs (miRNAs) and small interfering RNAs (siRNAs). The biogenesis and precise regulation of small RNA abundance are crucial for plant growth, development, genomic stability, and the resistance to both abiotic and biotic stresses. In this study, we used Arabidopsis thaliana, the model plant, to study the mechanism of RNA-directed DNA methylation (RdDM), in which siRNAs can trigger DNA methylation and gene silencing. In addition, we investigated the mechanism of miRNA biogenesis and degradation. For …