Genomics Commons^™

Development Of An In Vitro Model Of Mitochondrial Dna Copy Number Depletion Via Stable Inducible Expression Of D1135a Mutant Dna Polymerase Gamma, Amanda L. Morin

Electronic Thesis and Dissertation Repository

Mitochondria are responsible for several crucial cellular processes and contain their own DNA (mtDNA) that exists in several copies. Variation of mtDNA copy number (mtDNA-CN) alters energy metabolism and can modify the epigenome and transcriptome. We hypothesized that inducible expression of polymerase-deficient D1135A dominant-negative DNA polymerase gamma (DN-POLG) would result in mtDNA-CN depletion. Here, an in vitro model expressing D1135A POLG was created using the Flp-InTM T-RExTM-293 stable inducible expression system. Stable integration was confirmed with PCR amplification and Sanger sequencing of post-integration genomic sequences. D1135A POLG expression was confirmed with Western blot of the FLAG-tag antibody. Induction of D1135A …

Investigating The Impact Of Transcription On Mutation Rates, Sarah Patterson

Theses and Dissertations

tRNA genes are highly transcribed and perform one of the most fundamental cellular functions. Although a universal pattern observed across all three domains of life is that highly transcribed genes tend to evolve slowly, tRNA genes have been shown previously to evolve rapidly. This rapid sequence evolution could result from relaxed selection, increased mutation rate, or a combination of both. Here, we use mutation-accumulation line sequencing data to show that tRNA genes accumulate more mutations than other gene types. Our results indicate that this elevated mutation rate is a consequence of both elevated transcription-associated mutagenesis and a lack of transcription-coupled …

Advances In Phaeodactylum Tricornutum Nuclear Engineering, Mark Pampuch

Electronic Thesis and Dissertation Repository

The marine diatom Phaeodactylum tricornutum has the potential to become an excellent platform for the sustainable production of valuable compounds and pharmaceuticals, but currently large-scale engineering of this organism remains a challenge due factors like inefficient genetic transformation protocols and a lack of accurate genomic data. This thesis addresses these two bottlenecks by (i) optimizing an electroporation protocol to P. tricornutum and (ii) remapping genomic data from a scaffolded genome assembly to a telomere-to-telomere genome assembly. An optimized transformation protocol was developed that could consistently transform blunt-ended and DNA with overhangs and yielded up to 1000+ colony forming units per …

Unique Transcriptional Profiles Underlie Osteosarcomagenesis Driven By Different P53 Mutants, Dhruv Chachad

Dissertations & Theses (Open Access)

Missense mutations in the DNA binding domain of the Trp53 gene are characterized as structural (p53R172H) or contact (p53R245W) mutations based on their effect on the conformation of the protein. These mutations show gain-of-function activities such as increased metastatic incidence as compared to p53 loss, often mediated by their interaction with a repertoire of transcription factors. These interactions are largely context specific. In order to understand the mechanisms by which these mutations drive osteosarcoma progression, we created a mouse model, wherein either the p53 structural mutant p53R172H, or the contact mutant, p53R245W, are expressed specifically in …

Mouse Genotyping Array-Based Analysis Of Variation At Single Nucleotide Polymorphic Loci In The Context Of Macro- And Micro-Environments, Freda Qi

Electronic Thesis and Dissertation Repository

Comparing genetic variation between populations can provide insight into selective pressures in the environment. The Mouse Diversity Genotyping Array (MDGA) is a low-cost, high-throughput tool developed to capture and analyze variation at single nucleotide polymorphic (SNP) loci in inbred mouse strains. However, its ability to assess genetic variation in non-inbred mice and associate SNPs with the environment has not been extensively studied. First, SNPs between laboratory inbred and wild-caught mice were compared. No SNPs were associated with either macroenvironment. Instead, SNPs reflected genealogy and inbreeding strategies, consistent with the MDGA’s intended use. Second, mutations at SNP loci were compared between …

Use Of Molecular Genetics To Investigate Population Structure And Swayback In Horses, Navid Yousefimashouf

Theses and Dissertations--Veterinary Science

The present research incorporated molecular genetic methods to 1) investigate the genetic basis of Juvenile Onset Lordosis or Swayback in the American Saddlebred horses; and 2) conduct a population genetic study to compare the Persian Kurdish, Persian Arabian and American Thoroughbred horse populations.

Juvenile-onset lordosis, or swayback, is a condition in horses where the conformational topline back curvature drops significantly within the first two years of life. The trait has a higher prevalence in Saddlebreds (5%). Prior research on them quantified the trait using a Measurement of Back Contour (MBC), defining an MBC of >7.0 centimeters as swayback, and8.0) MBC …

Molecular Analysis Of Epigenetic Memory Of Stress Establishment And Long-Term Maintenance In A Perennial Woody Plant, Jia Wen Tan

Theses and Dissertations--Plant and Soil Sciences

Plants adapt to extreme environmental conditions through physiological adaptations, which are usually transient. Recent research has suggested that environmental conditions can activate a memory of stress that can result in a primed response to subsequent stress events. While the effect of priming has been observed in many plants, the underlying mechanisms are puzzling and seldom studied. A large body of research has been developed in the last decade linking response to stress, stress priming, and memory of stress with epigenetic mechanisms. This understanding of plant epigenetics has opened the door to the application of epigenetics to crop improvement, such as …

Cell Signaling And Stress Response In The Yeast Saccharomyces Cerevisiae: A Study Of Snf1, Scott E. Arbet Ii

Graduate Theses, Dissertations, and Problem Reports

Saccharomyces cerevisiae are yeast that are unicellular eukaryotic organisms that are well studied as a model organism for understanding fundamental cellular processes. The ability of yeast to sense nutrient availability is crucial for their survival, growth, and reproduction. Yeast cells use various mechanisms to sense and respond to nutrient availability, including transporter-mediated uptake, receptor-mediated signaling, and sensing of metabolites. The subcellular localization of nutrient-sensing components is crucial for yeast function in nutrient sensing and signaling. Protein complexes, such as the AMP-activated protein kinase (AMPK) pathway, in nutrient sensing and response, as well as the downstream effects of these pathways …

Development Of Functional Markers For Resistance To Smut And Identification Of Genes Differentially Expressed In Response To Brown Rust In Sugarcane, Jose David Cortes

LSU Doctoral Dissertations

Smut, caused by Sporisorium scitamineum and brown rust, caused by Puccinia melanocephala, are two of the most important diseases that affect sugarcane production in Louisiana and worldwide. Smut continues to cause losses in the breeding program in Louisiana. Therefore, a QTL analysis was conducted to identify molecular markers associated with resistance in F₁ progeny (162) of a biparental cross between susceptible cultivar L 99-233 and resistant HoCP 96-540. Using 1,574 single-dose SNP markers, a total of 253 linkage groups (LG) were obtained with a genome coverage of 24,580.15 cM. Six QTLs were localized on five LGs. The highest …

Identification Of Quantitative Trait Loci (Qtls) For Resistance To Bacterial Leaf Streak: Xanthomonas Translucens Using Qtl And Association Mapping In Three Populations Of Soft Red Winter Wheat, Benjamin Tyler Meritt

LSU Doctoral Dissertations

Bacterial leaf streak (BLS) and black chaff, caused by Xanthomonas translucens pv. undulosa (Xtu), can be a very destructive disease of wheat, especially in the warmer, wetter areas of the Southeastern U.S. Yield losses of up to 40 percent have been recorded in some cases in southern wheat growing regions. With no effective agronomic or chemical method of disease control, identification of genetic resistance is seen as a promising solution. Three soft red winter wheat populations (GAWN, ARK-SNP, and AGS 2060- AGS 2035 DH) representative of soft red winter wheat germplasm in the southeastern U.S. developed by …

Chemosensory Receptors In Berghia Stephanieae: Bioinformatics And Localization, Kelsi L. Watkins

Masters Theses

Chemosensation is achieved through the binding of chemical signals to chemoreceptor proteins embedded in the membranes of sensory neurons. The molecular identity of these receptors, as well as the downstream processing of chemosensory signals, has been well studied in arthropods and vertebrates. However, very little is known about molluscan chemosensation. The identity of chemoreceptor proteins in the nudibranch mollusc Berghia stephanieae are unknown. Data from other protostome and molluscan studies suggest Berghia may use ionotropic receptors for some forms of chemoreception. This study used a bioinformatics approach to identify potential chemosensory ionotropic receptors in the transcriptome of Berghia. A …

Identification And Characterization Of Genetic Elements That Regulate A C-Di-Gmp Mediated Multicellular Trait In Pseudomonas Fluorescens, Collin Kessler

Electronic Theses and Dissertations

Microbial communities contain densely packed cells where competition for space and resources are fierce. These communities are generally referred to as biofilms and provide advantages to individual cells against immunological and antimicrobial intervention, dehydration, and predation. High intracellular pools of cyclic diguanylate monophosphate (c-di-GMP) cause cells to aggregate during biofilm formation through the production of diverse extracellular polymers. Genes that encode c-di-GMP catalytic enzymes are commonly mutated during chronic infections where opportunists display enhanced resistance to phagocytosis and antibiotics. Our lab uses an emergent multicellular trait in the model organism Pseudomonas fluorescens Pf0-1 to study the emergence of c-di-GMP mutations …

What I Talk About When I Talk About Integration Of Single-Cell Data, Yang Xu

Doctoral Dissertations

Over the past decade, single-cell technologies evolved from profiling hundreds of cells to millions of cells, and emerged from a single modality of data to cover multiple views at single-cell resolution, including genome, epigenome, transcriptome, and so on. With advance of these single-cell technologies, the booming of multimodal single-cell data creates a valuable resource for us to understand cellular heterogeneity and molecular mechanism at a comprehensive level. However, the large-scale multimodal single-cell data also presents a huge computational challenge for insightful integrative analysis. Here, I will lay out problems in data integration that single-cell research community is interested in and …

Characterizing Endogenous Dicer Products To Unravel Novel Rnai Biogenesis Pathways, Jacob Oche Peter

Dissertations

ABSTRACT

RNA interference (RNAi) is a pervasive gene regulatory mechanism in eukaryotes based on the action of multiple classes of small RNA (sRNA). Exploiting RNAi pathways in non-model systems have great potential for creating potent RNAi technologies. Here, we accessed RNAi-mediated control of gene expression in the two-spotted spider mite, Tetranychus urticae (T. urticae) using engineered dsRNA designed to modulate the host RNAi pathway and increase RNAi efficacy. Analysis of Dicer (Dcr) generated fragments revealed how exogenous RNAs access the host RNAi pathway in this animal, opening avenues for designing RNAi technology for their control. Further, some organisms …

Genomic Tools And Models For Investigating The Role Of Germline Diversity In Mouse Antibody Repertoire Development., Justin T. Kos

Electronic Theses and Dissertations

Given the diversity and complexity within immunoglobulin (IG) loci, effective mouse models first require characterization of intra-strain differences and construction of high-quality reference assemblies for IG loci in several representative strains. To understand light chain germline diversity across biomedically significant mouse strains, we profiled the expressed IGK and IGL repertoires of 18 commonly used laboratory mouse strains using AIRR-seq. Across strains, we observed germline IGKV sequences shared by three different IGK haplotypes and a more conserved IGLV germline repertoire among common laboratory strains. Pacific Biosciences (PacBio) Single-Molecule Real-Time (SMRT) sequencing was used to sequence and assemble bacterial artificial chromosomes (BAC) …

Functional Role Of Ppal And Potential For Moss In Industrial Applications., Susana Perez Martinez

Electronic Theses and Dissertations

This dissertation is an examination and characterization of the functional roles of PPAL. PROTEIN PRENYLTRANSFERASE ALPHA SUBUNIT-LIKE (PPAL) is a recently discovered gene. PPAL homologs are present in all plants and many animals, where its function is largely unknown. It is possible that PPAL could participate in prenylation processes since it shares similarity to the α subunits of known prenylation enzymes. Prenylation is a post-translational modification of proteins that involves the addition of a lipid moiety to proteins to facilitate membrane targeting and association and promote protein-protein interactions. Prenylation has important roles in plant growth and development, including …

The Genetics Of Pain: An Exploration Of Gene-By-Environment Interactions And Their Effects On Pain, Mohamad F. Fakhereddin

Electronic Thesis and Dissertation Repository

The findings presented in this dissertation are part of the bigger SYMBIOME project which aims to use the biopsychosocial model of pain to develop a prognostic clinical phenotype for people that experience musculoskeletal (MSK) trauma. Chapter 2 presents an exploratory analysis to assess the relationships between genetic polymorphisms and pain severity and interference. Early childhood trauma was also explored as a moderator between genetic polymorphisms and pain outcomes. For pain severity, major allele carriers (A/A and G/A) of FKBP5 rs9394314 reported significantly higher scores than minor allele carriers (G/G). Further, major allele carriers who had at least one adverse childhood …

Phylogenetic And Geographic Relationships Of Cheilostome Bryozoans In The Eastern Pacific, Hannah E. Lee

Cal Poly Humboldt theses and projects

The phylum Bryozoa is an incredibly diverse group of marine invertebrates with a widespread global distribution that is well suited for evolutionary studies but whose phylogenetic relationships are still poorly understood. Although recent studies on bryozoan taxonomies and phylogenies have increased, there is still a lack of assessment of species found at shallow water (<1 m) to intertidal depths. In this study, I aimed to expand the taxonomic sampling and assessment of the phylogenetic diversity of cheilostome bryozoans along the California coastline by utilizing mitochondrial DNA as well as inferring potential correlations between species presence and dispersal range both within and between rocky outer coast and sheltered harbor habitats. Illumina high-throughput sequencing was used to produce mitogenomes for cheilostome bryozoan samples collected off rocks from two rocky intertidal sites and off settlement panels from two harbor sites. Phylogenetic analyses generated evolutionary hypotheses of species relationships alongside geographic mapping of their distribution. This study identified 15 distinct species that represent 10 different families to form the first comprehensive phylogeny for multiple bryozoan families in California across a total range of approximately 973 km of coastline. Three genetically distinct species were found at multiple sites that are separated by a combination of rocky shores and sandy beaches, which indicates that the dispersal range of these species are not limited by geographic barriers along the coast of California. These results provide a future opportunity for further integration of this data with the phylogenies generated in this study to examine more robust evolutionary hypotheses for the phylogenetic and geographic relationships of Californian bryozoan species.

Getting To The Root Cause: The Genetic Underpinnings Of Root System Architecture And Rhizodeposition In Sorghum, Farren Smith

Graduate Theses, Dissertations, and Problem Reports

Plants are some of the most diverse organisms on earth, consisting of more than 350,000 different species. To understand the underlying processes that contributed to plant diversification, it is fundamental to identify the genetic and genomic components that facilitated various adaptations over evolutionary history. Most studies to date have focused on the underlying controls of above-ground traits such as grain and vegetation; however, little is known about the “hidden half” of plants. Root systems comprise half of the total plant structure and provide vital functions such as anchorage, resource acquisition, and storage of energy reserves. The execution of these key …

Mutant Kras Alters Extracellular Vesicle Microrna Sorting In Pancreatic Cystic Neoplasms, Rachel L. Dittmar

Dissertations & Theses (Open Access)

Pancreatic ductal adenocarcinoma (PDAC) is among the deadliest cancers by organ site with a 5-year survival rate of just 10.8%. This is largely because most patients do not experience symptoms until the disease has already metastasized. The best hope to cure PDAC is surgery, which can only be done with a curative intent at an early stage when the disease is localized. There are no reliable circulating, body-fluid-based biomarkers to detect early stage PDAC or its precursor lesions in a timely manner for effective surgical intervention. When potential PDAC precursor lesions, such as mucinous pancreatic cysts are found, there are …

Human 5’-Tailed Mirtrons Are Processed By Rnasep, Mohammad Farid Zia

Dissertations

Approximately a thousand microRNAs (miRNAs) are documented from human cells. A third appear to transit non-canonical pathways that typically bypass processing by Drosha, the dedicated nuclear miRNA producing enzyme. The largest class of non-canonical miRNAs are mirtrons which eschew Drosha to mature through spliceosome activity. While mirtrons are found in several configurations, the vast majority of human mirtron species are 5’-tailed. For these mirtrons, a 3’ splice site defines the 3’ end of their hairpin precursor while a “tail” of variable length separates the 5’ base of the hairpin from the nearest splice site. How this tail is removed is …

Insights Into Halophilic Microbial Adaptation: Analysis Of Integrons And Associated Genomic Structures And Characterization Of A Nitrilase In Hypersaline Environments, Sarah Sonbol

Theses and Dissertations

Hypersaline environments are extreme habitats that can be exploited as biotechnological resources. Here, we characterized a nitrilase (NitraS-ATII) isolated from Atlantis II Deep brine pool. It showed higher thermal stability and heavy metal tolerance compared to a closely related nitrilase.

We also studied integrons in halophiles and hypersaline environments. Integrons are genetic platforms in which an integron integrase (IntI) mediates the excision and integration of gene cassettes at specific recombination sites. In order to search for integrons in halophiles and hypersaline metagenomes, we used a PCR-based approach, in addition to different bioinformatics tools, mainly IntegronFinder.

We found that integrons and …

Understanding Potassium Toxicity Stress Responses Of The Extremophyte Schrenkiella Parvula Using Systems Biology Approaches, Pramod Pantha

LSU Doctoral Dissertations

Schrenkiella parvula is an extremophyte model closely related to Arabidopsis thaliana and Brassica crops. Its natural habitat includes shores of saline lakes in the Irano-Turanian region. It has adapted to grow in soils rich in multiple salts including Na⁺ and K⁺. I have investigated the genetic basis for high K⁺ tolerance in plants using S. parvula as a stress tolerant model compared to the premier plant model, Arabidopsis thaliana which is highly sensitive to salt stresses using physiological, ionomic, transcriptomic, and metabolomic approaches. Under high K⁺ stress, root system architecture changes significantly compared to control …

Comparative Genomics Methods And Applications, Emily N. Alden

Biomedical Sciences ETDs

Virtually all fields of biology have benefited from the advancements in comparative genomics technologies, specifically in the study of evolution. In this dissertation I develop and use comparative genomic technologies to investigate the novel SARS-CoV-2 virus, assembly the first genome of the black lace domestic angelfish and identify germline genetic variants associated with altered breast cancer-specific survival. Our genome tiling array for the novel coronavirus presents a rapid and cost-effective method to sequence the entire viral genome and can be used to track the rapid evolution of viral variants in the population. The domestic angelfish is a member of the …

Genomic Studies Of Beaf-32 In Drosophila, John Keller Mckowen Iii

LSU Doctoral Dissertations

Compared to humans, the model organism Drosophila melanogaster is particularly gene dense and encodes several insulator binding proteins (IBP) to aid in its genome organization. Our focus of research is a particular IBP, Boundary Element-Associated Factor of 32kD (BEAF). BEAF primarily binds near the promoters of constitutively active housekeeping genes. It is thought to help maintain the active state of these genes by preventing the spread of repressive chromatin. Additionally, the enhancer blocking activity of BEAF is thought to prevent aberrant activation or silencing of genes. BEAF appears to be ubiquitously expressed among cells and tissues, albeit at varying levels. …

Insights Into Leptopilina Spp. Immune-Suppressive Strategies Using Mixed-Omics And Molecular Approaches, Brian Wey

Dissertations, Theses, and Capstone Projects

Host-parasite interactions influence the biology of each over the course of evolution. Parasite success allows for the passage of potent virulence strategies from generation to generation. Host success passes stronger immunity and resistance strategies to the following generations as well. Only by studying both partners within their natural contexts can we begin to understand the relationship between the two and how immune mechanisms and virulence strategies interact as a molecular arms race.

In this work, we focus on a natural host-parasite pair, the Drosophila-Leptopilina model. Leptopilina species are parasites of several fruit fly species, including Drosophila melanogaster. This model …

Effects Of 4-Methylcyclohexanemethanol On Stress Response Pathway Regulators, In Saccharomyces Cerevisiae, Suk Lan Ser

Graduate Theses, Dissertations, and Problem Reports

Hydrotropes are small molecules capable of inducing liquid-liquid phase separation by altering the solubility and conformation states of organic compounds that are increasingly becoming important in organizing chemical reactions and regulating complexes. They prevent protein aggregation causing these proteins to form condensates. Mediator, a highly conserved multi-subunit complex, plays an important role in transcription. Med15, a subunit found within the tail domain of the Mediator complex, works with stress-induced transcription factors and is regulated by many kinases, including CDKs and the AMP kinase, Snf1. Living cells respond by changing molecular and cellular pathways when they are exposed to stressful conditions. …

Composition And Homology In The Taxonomic Classification Of Escherichia Coli, Tanya Irani

Theses and Dissertations (Comprehensive)

As new techniques have been introduced, specifically the possibility of complete genome sequencing, better methods of defining bacterial species have also been proposed. One of the most recently proposed methods, using bioinformatic techniques, is to calculate the average nucleotide identity (ANI) between the homologous genome segments of different isolates. Another method for species discrimination that has been tested successfully is the similarity of DNA compositional signatures. However, in a recent update, DNA signatures split the available Escherichia coli complete genomes into three groups. To check if this result was consistent with such genomes belonging to different species, we tested methods …

3d Genome Architecture Under Stress: A Survey Of Ionizing Radiation, Progeria, And Osmotic Stress, Jacob Tyler Sanders

Doctoral Dissertations

The human nucleus contains 2 meters of DNA which is intricately folded into a three-dimensional (3D) structure. It has become increasingly clear that this 3D structure plays an important role in the expression of genes. Proper gene expression is necessary for cellular homeostasis, cell state, and response to environmental/physical perturbations. Faithful repair of damage DNA damage is necessary to prevent genomic aberrations, such as translocations, which may lead to misregulation of gene expression. Hi-C, a sequencing technique that labels proximal chromatin interactions, provides a clearer picture of how the genome is spatially organized within the nucleus. Here, we discuss the …

Carbon Metabolism In Cave Subaerial Biofilms, Victoria E. Frazier

Masters Theses

Subaerial biofilms (SABs) grow at the interface between the atmosphere and rock surfaces in terrestrial and subterranean environments around the world. Multi-colored SABs colonizing relatively dry and nutrient-limited cave surfaces are known to contain microbes putatively involved in chemolithoautotrophic processes using inorganic carbon like carbon dioxide (CO₂) or methane (CH₄). However, the importance of CO₂ and CH₄ to SAB biomass production has not been quantified, the environmental conditions influencing biomass production and diversity have not been thoroughly evaluated, and stable carbon and nitrogen isotope compositions have yet to be determined from epigenic cave SABs. …