Genetics and Genomics Commons^™

Genetic Screen For Regulators Of Pol4, A Dna Repair Polymerase In Saccharomyces Cerevisiae, Pasang Dolma Sherpa

Theses and Dissertations

In Saccharomyces cerevisiae, DNA polymerase 4 (POL4) is the beta repair polymerase, the product of the POL4 gene, and is involved in base excision repair (BER) and microhomology-mediated end joining (MMEJ). Despite its involvement in these repair pathways and its conservation across eukaryotes, deletion of POL4 shows no detectable phenotype under standard laboratory conditions. I hypothesized that unknown genes act as backup systems, providing redundant activities that allow pol4Δ cells to survive. To test this, a genetic screen for mutants showing synthetic lethality with pol4Δ was implemented. I constructed a strain lacking the POL4 gene and carrying …

Metagenomic Profiling Of Gut Microbiome Signatures Across Liver Disease Stages And Hcv-Related Hepatocellular Carcinoma In Egyptian Patients, Marwa A. Zahra

Theses and Dissertations

Dysbiosis in the gut microbiome, particularly concerning the synchronous crosstalk between the gut and the liver, has been associated with various diseases. This study profiles the gut microbiome in liver diseases among Egyptian patients, with a focus on the hepatitis C virus (HCV) and hepatocellular carcinoma (HCC), both of which are highly prevalent in Egypt. Utilizing shotgun metagenomic sequencing, we analyzed microbial gene catalogs and taxonomic profiles from 46 Egyptian patients categorized into five groups: healthy individuals, liver disease patients of different etiologies, post-HCV, treated HCV, and HCV-HCC patients. Healthy and treated HCV patients exhibited distinct microbial profiles characterized by …

Comparative Evolution Of Caenorhabditis Hermaphrodites, James Francis Kennedy

Theses and Dissertations

The Caenorhabditis genus produced three independently-evolved hermaphroditic species, C. elegans, C. briggsae, and C. tropicalis. This convergence happened by the independent co-option of male programs for use in a female body. This required two distinct steps: (1) mutations in the sex-determination pathway that activated spermatogenesis in XX animals, and (2) mutations that expressed one of the redundant sperm activation signals in XX animals. My project focused on characterizing how sex-determination genes work in C. briggsae and C. tropicalis. Loss-of-function alleles were used to compare the core sex-determination pathway to that of C. elegans. I found that the somatic sex-determination pathway …

The Yeast Checkpoint Kinase Mec1p Functions In Transcription Termination By Facilitating Recruitment Of Pcf11p And Regulating The Torpedo Exonuclease Rat1p, Riddhi Patel

Theses and Dissertations

My dissertation includes two projects, centered on transcription regulation by checkpoint kinases of the DNA damage response (DDR). The first project focused on the role of checkpoint kinase Mec1p in transcription termination and regulation of the torpedo exonuclease Rat1p. Termination, closely linked with pre-mRNA 3’ processing, dissociates RNA polymerase II (RNAPII) from DNA and releases the nascent RNA transcript. Efficient termination is required for maintaining a pool of RNAPII that is available for re-entry into new transcription cycle. Previous results showed that inactivation of Mec1p in the absence of exogenous genotoxic stress downregulates the efficiency of transcription termination. This study …

Metabolic Syndrome Beyond Diagnostic Criteria: Population-Scale Integrative Metabolomics Characterization, Marwa Talal

Theses and Dissertations

Background: Metabolic syndrome (MetS) is a complex cluster of interrelated metabolic abnormalities associated with elevated cardiometabolic risk. While diagnosis is based on well-established five clinical criteria, these may overlook early or atypical metabolic alterations. Large-scale metabolomic profiling offers an opportunity to identify biochemical signatures of MetS beyond diagnostic bias and to evaluate their relative importance across different presentations of the syndrome.

Methods: Data from 117,147 UK Biobank participants were analyzed in a cross-sectional design. High-throughput NMR quantified 75 circulating metabolites, for. Univariate analyses, MetS subtype stratification, and elastic net models with SHAP interpretation were applied to assess feature …

Characterization Of Microrna Expression In Neuron-Enriched Extracellular Vesicles During Early Life, Allison Molen

Theses and Dissertations

Extracellular vesicles (EVs) are membrane-bound sacs released by cells that carry molecular cargo reflective of their cell of origin. EVs enriched using L1 cell adhesion molecule (L1CAM) as a marker of putative neuronal origin can cross the blood–brain barrier and provide a minimally invasive window into brain-related processes. Exosomal microRNA (miRNA) regulate gene expression and have been implicated in psychiatric disorders, including major depressive disorder (MDD). However, measuring and analyzing miRNA from L1CAM-positive EVs presents substantial analytical challenges due to low abundance and sparse detection across samples.

Plasma samples from participants recruited through the Mid-Atlantic Twin Registry (MATR) were used …

Sex In Plants: Birth, Death, And Trying To Survive In Changing Climates, Elena M. Meyer

Theses and Dissertations

Plant mating systems are key determinants of fitness. Angiosperms exhibit a wide variety of reproductive strategies, including self-fertilization (or selfing), outcrossing, and mixed mating. It has been estimated that up to 43% of plant species are capable of selfing, and selfing has been hypothesized to provide reproductive assurance where opportunities for mating may be limited, such as in marginal environments. However, questions regarding the overall distribution of selfing rates across angiosperms, the maintenance of mixed mating in the face of inbreeding depression, and the impact of self-fertilization on diversification rates remain incompletely resolved. Here, we explore the dynamics of self-fertilization …

Building A Cell Specific System For In Vivo Rna Imaging Of The Endogenous Actin Gene In C. Elegans, Jasmine A. Huerta Canete

Theses and Dissertations

Messenger RNA (mRNA) plays a crucial role in protein synthesis and cellular processes, important for the development of cells such as neurons. When dysregulation occurs, it can lead to outcomes such as aberrant translation, causing neurodegenerative conditions to arise. Unfortunately, the localization of mRNA in an in vivo cell specific manner is still not understood. To address this, we decided to develop a cell-specific system to image RNA in vivo, within the organism known as C. elegans with a focus on the actin gene. The Actin gene encodes for an important cytoskeleton protein expressed ubiquitously, vital for the cell …

From Gametes To Genes: Genetic Quality Assessment Of Anuran Cryopreserved Spermatozoa And Derived Embryos, Trinity Isabella Kassuhn

Theses and Dissertations

Sperm cryopreservation is an important tool within the suite of assisted reproductive technologies (ART) as it enables long-term storage of genetically valuable gametes. However, knowledge of the diagnostic criteria for assessing sperm quality and the genetic consequences of using cryopreserved sperm in amphibians is limited. This gap has raised concerns in captive breeding and reintroduction programs regarding the potential impact that cryopreserved sperm and the derived embryos may have on a population. The thesis aims to investigate how sperm cryopreservation affects the genetic material in both sperm and resulting embryos, with implications for in situ and ex situ amphibian populations. …

Exploring Transcriptional Stress Responses In Sorghum And Evolutionary Insights Into Yth Domain Proteins Across Plants, Shikha Bharti

Theses and Dissertations

Understanding how plants respond to abiotic stress is crucial for enhancing crop resilience in the face of climate change. This thesis explores plant stress adaptation mechanisms through two interlinked studies that address different aspects of gene regulation. The first study investigates the transcriptional dynamics of Sorghum bicolor under drought and heat stress at 1-hour and 6-hour time points. By employing 3'-end RNA sequencing, this study provides a comprehensive temporal view of gene expression changes, revealing stress-responsive transcription factors, hormone-associated pathways, and chromatin regulators. The comparative analysis highlights both common and distinct molecular responses between drought and heat stress, providing insights …

Transformation With Genes To Improve Lipid Production And Barcoding To Identify Unknown Algal Species, Michelle T. Rada

Theses and Dissertations

With the rising demand for alternative fuels, algal-based biofuels are a promising, sustainable source that meets commercial interest while producing lower greenhouse gas emissions compared to fossil fuels. This thesis explored two studies, evaluating microalgae for their future potential in lipid yield for biofuel production.

The first study involved developing a cost-efficient electroporation protocol that allowed for the genetic transformation of Chlamydomonas reinhardtii using the pChlamy_4 vector, which supports future cloning of genes to enhance lipid production. Parameters affecting DNA uptake and integration into algal genomes were studied: the effect of cell density, the settings of the electroporation device, and …

Foxo Factors’ Ability In Binding To And Inducing Tcf7 In Glioblastoma Cells, Stephanie Oyervides

Theses and Dissertations

Glioblastoma Multiforme (GBM) is an aggressive astrocytoma tumor type with a poor prognosis and limited immunotherapeutic options for those inflicted. Stem gene expression of this cancer indicates a direct relationship with the transcription factors, Forkhead box subfamily O (FOXO-1, -3 and - 4). These transcription factors are evolutionarily conserved, partially redundant. They are involved in diverse and fundamental biological processes such as cell survival, stem cell homeostasis, cell fate determination, cell cycle maintenance, metabolism, and apoptosis. Increasing evidence suggests interconnectivity between the WNT Pathway and FOXO transcription factors; however, the mechanism and full extent to which these interactions play a …

Cloning And Heterologous Expression Of Human Nachrs And A Unique Spider Venom Toxin, Christine M. Vega

Theses and Dissertations

Drug development research has long focused on synthesizing novel therapeutics while overlooking isolation from naturally available sources. Recently, the discovery of the therapeutic effects of highly bioavailable animal venom caused the field of venom research to soar in popularity. Animal venom serves as a natural, sophisticated tool optimized over millions of years by evolution with the ability to bind to ion channels such as nAChRs, non-specific ligand-gated ion channels distributed throughout the human nervous system, with high selectivity and specificity. However, purifying individual venom toxins from crude venom is challenging due to its availability. Therefore, synthesizing large quantities of venom …

Developing A Small Molecule To Inhibit Hsf1 Expression In Cancer And Evaluating Natural Genetic Variation In Small Molecule Toxicity., Michaela Kendal Foley

Theses and Dissertations

Each year cancer affects nearly 20 million people worldwide and genetic differences across populations can impact cancer onset and progression. Specifically, tumors with high levels of HSF1, the master regulator of the cytoprotective heat shock response (HSR), are correlated with poor patient outcomes in multiple cancers such as prostate, breast, and melanoma. Subsequently, the development of pharmacological inhibitors of HSF1 represents a promising strategy for anticancer therapeutics. Using a luciferase-based transcriptional reporter, two small molecule libraries were screened for inhibitors of HSF1 expression in human embryonic kidney cells, yielding ten compounds that decrease HSF1 expression. To identify if cancer lines …

Barriers In Receiving A Diagnosis Of Sanfilippo Syndrome: Perceptions From Healthcare Providers And Caregivers, Cassidy Lena

Theses and Dissertations

Sanfilippo syndrome (MPS III) is a rare, degenerative condition characterized by symptoms impacting neurological functioning, behavior, and quality of life. Diagnosis is often not made until three to six years of age, but comprehensive and effective symptom management have been reported to optimize patient longevity. The aim of this study was to identify barriers to diagnosis and the corresponding impact on patients. This study surveyed healthcare providers and caregivers of individuals with Sanfilippo syndrome. Both quantitative and qualitative methods were employed to assess provider knowledge and comfortability in managing Sanfilippo syndrome. Additionally, it explored caregiver perspectives on healthcare system navigation, …

Genetics Education Booklets Designed For Individuals With Intellectual Disability: Perspectives From Adults With Intellectual Disability And Genetic Counselors, Audrey Hyun Sook Parrott

Theses and Dissertations

Visual aid tools have been consistently suggested across literature aimed at identifying methods of improving health and genetics services for individuals with intellectual disability (ID). Aids written in plain language are suggested most often. The study intends to gain perspectives from adults with ID (AWID) and genetic counselors (GCs) on Easy Read genetics educational booklets designed for individuals with mild ID. We anticipate that GCs will find the booklets to be useful and accurate, and that AWID will find the booklets to be helpful to their understanding and comprehensible. The AWID were assessed via a self-reported survey, cognitively adapted for …

An Exploratory Study Of Disclosure Of X-Linked Conditions Between Mothers And Daughters, Madge Isabella Stuhlreyer

Theses and Dissertations

Carriers of X-linked conditions, both asymptomatic and symptomatic, face unique challenges regarding their experiences navigating the healthcare system and understanding implications of their carrier status. Studies show that mothers are known to be the main communicators of genetic information within their families, but in families affected with X-linked conditions, communication between mothers and daughters are hindered by factors such as lack of knowledge about the condition and reproductive implications, lack of emotional support, anxiety, and uncertainty about how to initiate these conversations. The purpose of this study was to explore the motivations behind mothers' decisions to initiate conversations with their …

Increasing Diversity In The Genetic Counseling Profession: Determining Effective Career Education Strategies For Underrepresented Youth, Bryel Marie Frasch

Theses and Dissertations

Genetic counseling is a professional career path that is lacking in diversity, and diversity in healthcare has been shown to improve health outcomes. Studies suggest student engagement as a way to increase diversity, as early knowledge of genetic counseling increases the likelihood of considering it as a career and is especially true for racial or ethnic minoritized students. This study focused on educating high school students underrepresented in genetic counseling about the career and exploring the effectiveness of two different types of education methods (video vs in-person) to give valuable information for future outreach efforts. Upward Bound and Federal TRIO …

Newborn Screening For X-Linked Adrenoleukodystrophy: Experiences, Perspectives, And Future Directions For Genetic Counseling, Sophia Salvatore

Theses and Dissertations

There is a notable lack of research regarding genetic counseling practices for infants with screen-positive results for X-linked adrenoleukodystrophy (X-ALD) via newborn screening (NBS). The exploratory study aimed to understand the experiences of genetic counselors providing follow-up care for these infants, assess the complexities associated with NBS for X-ALD, identify potential gaps in genetic counseling practices, and describe the subsequent impact on patient care. A mixed-methods approach was utilized, incorporating an initial survey and optional semi-structured interviews with practicing genetic counselors who had seen a minimum of five cases of infants with screen-positive results for X-ALD in the last two …

A Study To Identify The Causal Rare Genetic Variants In Primary Open And Closed Angle Glaucoma, Pseudoexfoliation Syndrome, And Associated Glaucoma, Suganya K

Theses and Dissertations

BACKGROUND: Glaucoma is the second most common cause of blindness globally typically diagnosed with a triad of clinical symptoms of increased intraocular pressure (IOP) with associated optic disc, optic nerve head (ONH) changes, and visual field defects. Genetic and environmental factors are some of the strong aetiology factors for glaucoma and identification of these factors has a potential implication in the management of the disease and its outcome. There is a paradigm shift towards understanding the genetics of glaucoma, wherein the variants in the nuclear, mitochondrial genome and other regulatory regions are being identified as contributing risk factors.

METHODOLOGY AND …

Identification Of Novel Argonaute Proteins Using A Metagenomic Mining Approach, Lobna Abdallah Ghonaim

Theses and Dissertations

Gene editing is one of the most promising tools in science. It enables precise modifications of an organism's genetic material. Metagenomics is considered a powerful tool that unlocks the broad genetic potential found in uncultured microbial communities. Exploring the genetic diversity of uncultured microbial communities helps identify novel functional proteins with unique properties and make the best use of these diverse microbial ecosystems.

We developed and employed a metagenomic-based approach to mine more than 1000 metagenomes for prokaryotic argonaute proteins (pAgos), a potential gene editing machinery encoded in bacterial and archaeal genomes. Our workflow involved strict quality control, sequence assembly, …

Role Of An Smc-Like Protein, Recn, In Reca-Mediated Homology Search During Double-Strand Break Repair Via Homologous Recombination, Afroze Abdehaque Chimthanawala

Theses and Dissertations

The most deleterious form of DNA damage is the formation of a double-strand break (DSB). If left unrepaired or repaired incorrectly, DSBs can result in genome rearrangements, mutations, or even cell death. Hence, cells across domains of life have resorted to homologous recombination (HR) for the faithful repair of DSBs. A critical step in homologous recombination is the search for the intact homologous sequence by the break ends, termed ‘homology search’. This process is not well understood in vivo, especially when the break site and intact homologous template are not positioned adjacently.

Spatial reorganization of chromosomes is maintained by structural …

Investigating The Thermodynamic Properties Of Fat10 And Fat10ylated Proteins, Aravind R

Theses and Dissertations

Degradation of proteins by the proteasome is crucial in regulating protein levels in the cell. Post-translational modifications, such as ubiquitylation and Fat10ylation, trigger proteasomal degradation of the substrate proteins. While ubiquitylation orchestrates multiple cellular processes, Fat10ylation is primarily involved in the inflammatory response. Unlike ubiquitin, recycled upon substrate degradation, Fat10 is degraded along with its substrate. Although the thermodynamic properties of the substrate are critical for effective proteasomal degradation, they remain poorly understood for the Fat10-proteasome pathway.

Here, we demonstrate that Fat10 exhibits markedly lower thermodynamic stability and faster unfolding kinetics compared to ubiquitin. This is due to the absence …

Beyond Homogeneity: Exploring Causal Heterogeneity In Psychopathology, Philip B. Vinh

Theses and Dissertations

Traditional models in psychiatric research often impose assumptions of causal homogeneity, treating population-level associations as reflective of uniform underlying mechanisms. This dissertation challenges that assumption by introducing statistical and machine learning frameworks designed to detect and model causal heterogeneity in the development of psychopathology. Central to this approach is the advancement of finite mixture structural equation modeling (FM-SEM) to identify latent subgroups characterized by distinct, and sometimes opposing, causal pathways.

The dissertation comprises three integrated empirical studies. The first introduces mixDoC, a finite mixture extension of the classical Direction of Causation (DoC) model applied to twin data, enabling the detection …

Doves And Symbiotic Bacteria: Whole-Genome Assembly And Phylogenomic Inference, Mariam Topchyan

Theses and Dissertations

Part 1

I examined a potential source of variation in phylogenetic inference, investigating whether handling single-nucleotide polymorphisms (SNPs) through different methods during reference-guided genome assembly of pigeon and dove species impacts phylogenetic reconstruction and inference. Specifically, I created a custom consensus base calling tool that handles allelic variation through two different approaches, either ignoring heterozygous sites by denoting them as an ambiguous character “N,” or using a pseudo-random choice between supported base variants. Through reference-guided assembly of 108 dove species, I generated two datasets of alignments using both consensus calling methods, created two trees from both datasets via supermatrix and …

Exploring The Role Of Transcription Factor Nrf1 In Autophagy And Inhibiting The Nrf1 Bounce-Back Response, Madison A. Ward

Theses and Dissertations

Cells exposed to proteotoxic stress invoke adaptive responses aimed at restoring proteostasis. Our previous studies have established a firm role for the transcription factor Nuclear factor-erythroid derived-2-related factor-1 (Nrf1) in responding to proteotoxic stress elicited by inhibition of cellular proteasome. Following proteasome inhibition, Nrf1 mediates the synthesis of new proteasomes, thus enabling cells to mitigate proteotoxic stress. Here, we report that under similar circumstances, multiple components of the autophagy-lysosomal pathway (ALP) were transcriptionally upregulated in an Nrf1-dependent fashion, thus providing the cells with an additional route to cope with proteasome insufficiency. In response to proteasome inhibitors, Nrf1-deficient cells exhibited profound …

Karyotyping As A Method To Verify Phylogenetic Relationships Among The Enneacanthus Species, Ophelia A. Anderson

Theses and Dissertations

The Enneacanthus genus consists of three species of freshwater fish endemic to eastern North America: E. obesus (Banded Sunfish), E. gloriosus (Blue Spotted Sunfish), and E. chaetodon (Black Banded Sunfish). Previous studies using molecular data suggest that E. obesus and E. gloriosus are more closely related, with E. chaetodon as the most distantly related species in the genus. This study investigates the phylogenetic relationship among the Enneacanthus species, using karyotype characteristics - chromosome number, morphology and fundamental number - as comparative metrics. Chromosome spreads were obtained from scale and gill epithelium samples collected between 1993 and 1994. Prepared slides …

Investigating Mitochondrial Stress Response Mechanisms In Aging, Aileigh E. Daniel

Theses and Dissertations

Mitochondrial dysfunction is widely recognized as a key contributor to aging and age-related diseases. The concept of mitohormesis suggests that low levels of ROS can activate stress-responsive transcription factors, promoting adaptive mechanisms that enhance longevity. We hypothesized that changes in protein abundance under conditions of mild mitochondrial stress reflect an adaptive response, and that commonly altered proteins across diverse genetic backgrounds of mitochondrial stress can help identify key regulators of stress resilience and aging. Our study identified conserved mitochondrial stress response pathways and highlighted candidate regulators for further investigation. These regulators appear to impair mitochondrial energy production by downregulating ATP …

Enhancing Clinical Trial Matching In Molecular Diagnostics: Using Natural Language Processing And Clustering Approaches In Hematological Malignancies, Gillian Fanning

Theses and Dissertations

Clinical trial matching is a critical component of personalized medicine, particularly in the management of hematologic malignancies. At Virginia Commonwealth University (VCU) Health, the Molecular Diagnostics (MDX) Lab produces somatic variant reports and recommends clinical trials based on the presence of clinically significant mutations. However, the current manual trial recommendation process is time-intensive and lacks scalability.

This study introduces a computational framework to streamline and standardize clinical trial matching using natural language processing (NLP) and unsupervised clustering. Trial brief descriptions were analyzed to extract frequent terms, and trials were grouped based on term similarity using joint dimensionality reduction and clustering. …

The Relationship Between Cardiac Patient Beliefs And Experiences With Insurability And Their Decisions On Whether Or Not To Pursue Genetic Testing, Julia Schoeni

Theses and Dissertations

Since the enactment of the Genetic Information Non-Discrimination Act (GINA) in 2008, genetics providers have been incorporating conversations about GINA in pre-test counseling. There is currently limited evidence of the effects of personal or family histories of cardiomyopathy or aortopathy and associated genetic testing on patients seeking insurance policies not protected by GINA, including life, long term care, and disability insurance. This study aimed to determine whether individuals with a personal or family history of cardiomyopathy or aortopathy are having conversations about future insurability with their healthcare providers and how they perceive their ability to get these insurances when deciding …