Genetics and Genomics Commons^™

Statistical Methods For Gene Selection And Genetic Association Studies, Xuewei Cao

Dissertations, Master's Theses and Master's Reports

This dissertation includes five Chapters. A brief description of each chapter is organized as follows.

In Chapter One, we propose a signed bipartite genotype and phenotype network (GPN) by linking phenotypes and genotypes based on the statistical associations. It provides a new insight to investigate the genetic architecture among multiple correlated phenotypes and explore where phenotypes might be related at a higher level of cellular and organismal organization. We show that multiple phenotypes association studies by considering the proposed network are improved by incorporating the genetic information into the phenotype clustering.

In Chapter Two, we first illustrate the proposed GPN …

Unusual Chromosome Configurations: Evaluation Of Sex Univalent And Trivalent Chromosome Models, Ashley B. Borseth

Master’s Theses

Aneuploidy, or abnormal number of chromosomes in a haploid set, in XY/XX organisms has consequences that can impede physical and cognitive development. To prevent aneuploidy, cellular division relies on the correct position of paired chromosomes and subsequent segregation in the meiotic program. If connections between paired chromosomes sever or errors in chromosome contraction towards spindle poles arise, aneuploidy occurs. Many arthropod species have chromosomes that naturally do not pair, or that pair differently than typical autosomes. Through the evaluation of such systems, novel insights into chromosomal coordination and positioning may be revealed. The objective of this study is twofold: (1) …

Multi-Omic Analysis Of Vegetative Propagation Induced Plant Rejuvenation In Grapevines: Implications For The Generation Of Locally Adapted Cultivars Using Epigenetics, Tajbir Raihan

Theses and Dissertations--Plant and Soil Sciences

Epigenetic memory of the growing environment is a process capable of increasing plants’ resilience to abiotic stimuli. The cultivated grapevine is a long-living perennial species with a large corpus of research suggesting that plant adaptation to the environment has implications for the selection of genetic material in a changing climate. Moreover, vine age has been traditionally correlated with enhanced fruit quality. Recent studies have shown that environment/age-acquired traits in grapevine (e.g., adaptation to the growing environment and fruit/wine quality, respectively) are associated with epigenetic mechanisms. These studies also indicate that of propagation type affects the maintenance/erasure of the acquired traits …

Species-Specific Microsymbiont Discrimination Mediated By A Medicago Receptor Kinase, Xiaocheng Yu

Theses and Dissertations--Plant and Soil Sciences

Legumes form a mutualistic partnership with nitrogen-fixing bacteria to meet their nitrogen requirements. This collaboration leads to the development of root nodules, offering an ideal environment for the bacteria to convert atmospheric nitrogen into ammonia. A salient aspect of this symbiotic relationship is host range specificity, such that nodulation capacity and nitrogen fixation efficiency differ significantly between different host-bacterial combinations. Understanding the genetic basis of this specificity could pave the way for strategies to overcome the host range barrier. Sinorhizobium meliloti and Sinorhizobium medicae are two closely related species that display differential symbiotic behaviors with legume plants of the Medicago …

Prediction Of Kinase-Substrate Associations Using The Functional Landscape Of Kinases And Phosphorylation Sites, Serhan Yilmaz, Filipa Blasco Tavares Pereira Lopes, Mark R. Chance, Mehmet Koyutürk

Faculty Scholarship

Protein phosphorylation is a key post-translational modification that plays a central role in many cellular processes. With recent advances in biotechnology, thousands of phosphorylated sites can be identified and quantified in a given sample, enabling proteome-wide screening of cellular signaling. However, for most (> 90%) of the phosphorylation sites that are identified in these experiments, the kinase(s) that target these sites are unknown. To broadly utilize available structural, functional, evolutionary, and contextual information in predicting kinase-substrate associations (KSAs), we develop a network-based machine learning framework. Our framework integrates a multitude of data sources to characterize the landscape of functional relationships …

Can Testing The Environment For Severe Acute Respiratory Coronavirus Virus 2 (Sars-Cov-2) Be A Signal For Coronavirus Disease 2019 (Covid-19) Cases Among Nursing Home Staff?, Gabrielle M. Gussin, Raveena D. Singh, Izabela Coimbra Ibraim, Raheeb Saavedra, Thomas T. Tjoa, Micaila Curtis, Kristine P. Nguyen, Ilhem Messaoudi, Susan S. Huang

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Prior to widespread COVID-19 vaccination, nursing homes were required to perform comprehensive weekly testing of staff. After the vaccine became available, testing became symptom-based for vaccinated staff despite continued waves of different severe acute respiratory coronavirus virus 2 (SARS-CoV-2) variants. Nursing homes need pragmatic, affordable strategies to identify SARS-CoV-2–positive staff because financial and job-related pressures drive reluctance to disclose mild symptoms. We sought to determine whether positive environmental samples for SARS-CoV-2 could serve as trigger for comprehensive staff testing in lieu of weekly testing of all staff.

Correlates Of Sars-Cov-2 Anti-Rbd Igg Antibody Titers Among Persons Experiencing Homelessness In Los Angeles, Adeline Nyamathi, Sanghyuk S. Shin, Brianna M. Doratt, Alexandria Jones-Patten, Benissa Salem, Lillian Gelberg, Darlene Lee, Dana Garfin, Kartik Yadav, Alicia H. Chang, Kathryn White, Nicholas Arce, Ilhem Messaoudi

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Objectives: People experiencing homelessness (PEH) have been especially impacted by the COVID-19 pandemic, likely due to increased vulnerabilities stemming from chronic diseases, substance use, and mental health conditions.

Design: A case–control study to assess the presence of antibodies against SARS-CoV-2 among PEH and associations with key variables.

Sample: A convenience sample of 97 PEH in Skid Row, Los Angeles.

Measurements: A structured questionnaire assessing socio-demographic, mental health, drug and alcohol use, health care access, pandemic stress, and other COVID-19-specific questions.

Results: We found high anti-receptor binding domain (RBD) IgG titers among five of 15 PEH who reported no prior COVID-19 …

Maternal Obesity Blunts Antimicrobial Responses In Fetal Monocytes, Suhas Sureshchandra, Brianna M. Doratt, Norma Mendza, Oleg Varlamov, Monica Rincon, Nicole E. Marshall, Ilhem Messaoudi

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Maternal pre-pregnancy (pregravid) obesity is associated with adverse outcomes for both mother and offspring. Amongst the complications for the offspring is increased susceptibility and severity of neonatal infections necessitating admission to the intensive care unit, notably bacterial sepsis and enterocolitis. Previous studies have reported aberrant responses to LPS and polyclonal stimulation by umbilical cord blood monocytes that were mediated by alterations in the epigenome. In this study, we show that pregravid obesity dysregulates umbilical cord blood monocyte responses to bacterial and viral pathogens. Specifically, interferon-stimulated gene expression and inflammatory responses to respiratory syncytial virus (RSV) and E. coli were significantly …

Sars-Cov-2 Infection And Seroconversion Rates In Healthcare Providers Prior To Covid-19 Vaccine Rollout, Sanghyuk S. Shin, Miriam Bender, Delphine C. Malherbe, Hannah Vasquez, Brianna M. Doratt, Ilhem Messaoudi

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Objective: A 6-month longitudinal surveillance study of asymptomatic healthcare providers (HCP) was carried out at a large urban academic medical center in the United States to assess whether their job occupation with higher exposure risks to SARS-CoV-2 would equate with higher risk of contracting COVID-19 at the beginning of the pandemic before COVID-19 vaccines were available.

Methods: A longitudinal cohort study design was used to collect and analyze immunological and virological monitoring data and self-report survey assessments of personal protective equipment (PPE) availability, adherence to infection control guidelines, and time spent on COVID-19 wards.

Results: Among 289 eligible participants, SARS-CoV-2 …

Single-Dose Vsv-Based Vaccine Protects Cynomolgus Macaques From Disease After Taï Forest Virus Infection, Paige Fletcher, Kyle L. O'Donnell, Brianna M. Doratt, Delphine C. Malherbe, Chad S. Clancy, Joseph F. Rhoderick, Friederike Feldmann, Patrick W. Hanley, Thomas G. Ksiazek, Thomas W. Geisbert, Ilhem Messaoudi, Andrea Marzi

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Taï Forest virus (TAFV) is a lesser-known ebolavirus that causes lethal infections in chimpanzees and is responsible for a single human case. Limited research has been done on this human pathogen; however, with the recent emergence of filoviruses in West Africa, further investigation and countermeasure development against this virus is warranted. We developed a vesicular stomatitis virus (VSV)-based vaccine expressing the TAFV glycoprotein as the viral antigen and assessed it for protective efficacy in nonhuman primates (NHPs). Following a single high-dose vaccination, NHPs developed antigen-specific binding and neutralizing antibodies as well as modest T cell responses. Importantly, all vaccinated NHPs …

Transcriptional Profiling Of Immune Responses In Nhps After Low-Dose, Vsv-Based Vaccination Against Marburg Virus, Cecilia A. Prator, Brianna M. Doratt, Kyle L. O'Donnell, Justin Lack, Amanda N. Pinski, Stacy M. Ricklefs, Craig A. Martens, Ilhem Messaoudi, Andrea Marzi

Microbiology, Immunology, and Molecular Genetics Faculty Publications

Infection with Marburg virus (MARV), the causative agent of Marburg virus disease (MVD), results in haemorrhagic disease and high case fatality rates (>40%) in humans. Despite its public health relevance, there are no licensed vaccines or therapeutics to prevent or treat MVD. A vesicular stomatitis virus (VSV)-based vaccine expressing the MARV glycoprotein (VSV-MARV) is currently in clinical development. Previously, a single 10 million PFU dose of VSV-MARV administered 1–5 weeks before lethal MARV challenge conferred uniform protection in nonhuman primates (NHPs), demonstrating fast-acting potential. Additionally, our group recently demonstrated that even a low dose VSV-MARV (1000 PFU) protected NHPs …

Accucalc: A Python Package For Accuracy Calculation In Gwas, Jana Biová, Nicholas Dietz, Yen On Chan, Trupti Joshi, Kristin Bilyeu, Mária Škrabišová

Biomedical Sciences

The genome-wide association study (GWAS) is a popular genomic approach that identifies genomic regions associated with a phenotype and, thus, aims to discover causative mutations (CM) in the genes underlying the phenotype. However, GWAS discoveries are limited by many factors and typically identify associated genomic regions without the further ability to compare the viability of candidate genes and actual CMs. Therefore, the current methodology is limited to CM identification. In our recent work, we presented a novel approach to an empowered “GWAS to Genes” strategy that we named Synthetic phenotype to causative mutation (SP2CM). We established this strategy to identify …

Novel Feature Evaluation In Ultra-High Dimensional Right-Censored Data, With Applications To Head And Neck Cancer, Atika Farzana Urmi

Graduate Research Posters

Background: Head and neck cancer is the 6th most common cancer worldwide with an expected 1.08 million new cases each year. Such cancer data are ultra-high dimensional with thousands of clinical features and gene expressions, making it challenging for the traditional analytical tools to extract the potential biomarker for the cancer survival and control false discoveries. In addition, presence of heavy censoring can affect the screening procedures based on Kaplan-Meier (K-M) survival estimates.

Aim: To propose a model free, ultra-high dimensional feature screening method with two-dimensional survival outcome allowing false discovery rate (FDR) control.

Method: 516 primary tumor patients with …

Selective Gsk3b Overexpression In Medial Prefrontal Cortex Camkiia Cells Produces Sex-Specific Changes In Ethanol Self-Administration, Anxiety-Like Behavior, And Working Memory, Sam Gottlieb, Zachary Tatom, Michael F. Miles

Graduate Research Posters

Background: Glycogen synthase kinase 3 beta (Gsk3b) is central in a gene network regulated by ethanol in mouse medial prefrontal cortex (mPFC). GSK3B abundance/activity modulations regulate ethanol consumption, suggesting GSK3B could be a target in treating alcohol use disorder. However, the critical cell type in this ethanol response is not yet known, nor have sex differences in GSK3B modulations been fully investigated. Here we report results of GSK3B overexpression selectively in CamKIIa⁺ mPFC cells on multiple behaviors.

Methods: Mice underwent stereotaxic injections to overexpress GSK3B in mPFC CamKIIa⁺ cells or control virus (n=4-6/sex/virus). We assayed working …

Alzheimer’S Disease Genetics And Short-Chain Fatty Acid Treatment In Studies Of The Murine Gut Microbiome, Diana Zajac

Theses and Dissertations--Physiology

Elucidating the relationship of the gut microbiome in Alzheimer's Disease (AD) risk and pathogenesis is an area of intense interest. Since 60 to 80% of AD risk is related to genetics and APOE alleles represent the most impactful genetic risk factors for AD, their mechanism(s) of action are under intense scrutiny.

First, I conducted a study on APOE targeted replacement mice to investigate the impact of APOE alleles on the murine gut microbiome. The relative abundance of bacteria from the family Ruminococacceae and related genera increased with APOE2 status. The relative abundance of the class Erysipelotrichia increased with APOE4 status, …

Generation Of Chimeric Rhinoviruses Presenting Sars-Cov-2 Broadly Neutralizing Epitopes And Their Antigenicity Characterization, Danish Ansari

Biotechnology Theses

The global COVID pandemic is not yet fully under control as there were over 21 million new cases of SARS-CoV-2 infections and over 50,000 deaths globally as of January of 2022. A heavily mutated variant of concern, Omicron is responsible for most of these cases which demands an urgency for a new vaccine. NIH reports over 180 vaccine candidates that use various strategies currently in development. However, a recurring concern with these vaccines is that the continuous viral mutations decrease the efficacy of vaccines. Therefore, we proposed to construct a human rhinovirus (HRV) based chimeric virus containing highly conserved, broadly …

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

Graduate Theses, Dissertations, and Problem Reports (ETD)

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 …

Elucidation Of The Role Of Agouti-Signaling Protein Throughout Folliculogenesis And Early Embryonic Development In Cattle, Heather L. Chaney

Graduate Theses, Dissertations, and Problem Reports (ETD)

The oocyte expresses certain genes during folliculogenesis to regulate the acquisition of oocyte competence. Oocyte competence, which refers to the presence of imperative molecular factors in the oocyte that are critical for high oocyte quality, is directly related to the ability of the oocyte to result in a successful pregnancy following fertilization. Over the past few decades, the development and optimization of assisted reproductive technologies, particularly in vitrofertilization, have enabled the beef and dairy industries to advance cattle genetics and productivity. However, only approximately 40% of bovine embryos will develop to the blastocyst stage in vitro. In addition, bovine embryos …

Knockout Of Endospanin 1 Via Crispr In Zebrafish, Danio Rerio, Jared Kittinger

Williams Honors College, Honors Research Projects

I made endospanin 1 knockout (KO) zebrafish to examine its effects on lipid and bone metabolism. Endospanin 1, or leptin receptor overlapping transcript (leprot), is a cytosolic protein linked to the protein hormone leptin that influences the trafficking of leptin receptors to the plasma membrane of cells. Genes for endospanin and tyrosinase (a pigmentation enzyme) were targeted via a microinjection of guide RNAs and CRISPR Cas9 into zebrafish embryos at 2-4 cell stages. I was able to disrupt the endospanin 1 gene (based upon the disruption of tyrosinase), but very few mutant zebrafish fully developed into adults. Only low KO …

Advancing Methods Of Diet Analysis: A Case Study Using Degraded Merlin (Falco Columbarius) Prey Remains, Taylor A. Coon

Undergraduate Theses, Professional Papers, and Capstone Artifacts

Prey remains have long been used as a mechanism to approach diet analyses. As understanding diet is key to comprehending ecosystem dynamics, prey remains identification requires a unique methodological approach to determine diversity within a sample. With the advancement of technology, molecular protocols designed for species-specific identification have improved to incredible accuracy and precision. Yet, the visual identification method has remained a predominant technique within diet studies. With entry-level observers, we matched visual identifications with molecular-based methods to quantify the accuracy of the visual identification method. This study determined what fraction of visually identified prey remains could be correctly identified …