Characterizing Somatic Variants In Nanopore Data With Machine Learning, Shwethal Sayeeram Trikannad

Master's Projects

Oxford Nanopore Technology (ONT) is a popular long-read sequencer in genomics. However, its high base-calling error rate produces several sequencing artifacts. Detection of somatic variants in ONT sequenced tumor-normal samples remains challenging due to low frequencies. In this study, machine learning was applied to a dataset created by benchmarking ClairS output against HCC1395 and colo829 truth sets to classify variants and artifacts. Relevant features were engineered from sequence context and variant site characteristics to model artifact profiles. HistGradientBoostingClassifier achieved 0.876950 accuracy, outperforming all other models. Variant quality was the top predictor with an aggregate accuracy of over 85%. This work …

Phylogenetic Analysis Of Metabolic Enzymes In Hypoxic/Anoxic Conditions In Cetaceans And Cancer, Samerna A. Masih

Electronic Theses & Dissertations (2024 - present)

Cancer cells often exhibit a Warburg-like metabolism, which includes increased fatty acid synthesis and storage that help them survive in hypoxic conditions. This shift is marked by the heightened synthesis and accumulation of fatty acids, acting as a survival mechanism in low-oxygen environments (Baumann et al., 2016). Interestingly, deep-diving whales may utilize a similar metabolic pathway to produce wax esters during their prolonged dives.

Our study focused on exploring the genetic and metabolic similarities between breast cancer cells and deep-diving whales, using computational analyses to investigate lipid metabolism genes. We looked for evolutionarily conserved variations that might reveal adaptive mechanisms …

Analysis Of Differential Gene Expression In Androgen-Independent Clones Derived From The Mycap Pca Cell Line, Jessie L. Tignor, Melanie Sinanian, Richard Inho Joh, David Gewirtz, Jason Reed

Undergraduate Research Posters

Androgen deprivation therapy (ADT) is a primary treatment strategy for prostate cancer (PCa), yet many tumors eventually develop androgen independence, leading to treatment resistance. To investigate the molecular changes underlying this transition, we analyzed differential gene expression in four androgen-independent (AI) clones derived from the Myc-CaP prostate cancer cell line using RNA sequencing. Gene expression profiles were compared to the parental Myc-CaP line, and differentially expressed genes (DEGs) were identified using DESeq2 and edgeR. The AI clones exhibited significant downregulation of senescence-associated genes, including Ezh2 and lamin B1, suggesting a loss of senescence-related chromatin repression. Additionally, upregulation of Wnt pathway …

Methods In Statistics, Machine Learning, And Deep Learning For Combining Multi-Omics Dataset, Md Mutasim Billah

Dissertations, Master's Theses and Master's Reports

Transcriptome-wide association studies (TWAS) have emerged as a powerful strategy to bridge genome-wide association studies (GWAS) with gene regulatory mechanisms by integrating genotypic data with gene expression data. While early TWAS methods typically rely on linear models and single-tissue expression references, recent advances underscore the need for flexible, multi-tissue approaches that can capture heterogeneous regulatory architectures and tissue-specific expression patterns. This dissertation introduces a three‑part research project that advances multi‑tissue transcriptome‑wide association studies (TWAS) along complementary axes of methodology, statistical power, and modelling flexibility.

In chapter One, TWAS‑CTL introduces a two‑stage cross‑tissue learner that trains any user‑chosen single‑tissue imputers (STLs) …

Timigp: A Computational Framework To Determine The Tumor Immune Microenvironment Associated With Prognosis And Immunotherapy Response, Chenyang Li

Dissertations and Theses (Open Access)

Accumulating evidence has suggested that the tumor immune microenvironment (TIME) drastically impacts cancer patients’ clinical outcomes, including prognosis and immunotherapy response. However, understanding TIME remains challenging due to its complexity and heterogeneity. In this dissertation, we introduce TimiGP (Tumor Immune Microenvironment Illustration based on Gene Pairs), a computational framework designed to address this challenge. Leveraging single-cell RNA-seq (scRNA-seq) and bulk gene expression data alongside clinical information, TimiGP constructs a cell-cell interaction network that elucidates the relationship between immune cell function and relevant clinical outcomes, such as prognosis and treatment response. With immunological insights, these cell-cell interactions also facilitate the development …

Investigating The Rare Aneuploid Cells In Normal Breast And Therapeutic Resistance In Triple Negative Breast Cancer Using Single Cell Genomics, Yiyun Lin

Dissertations and Theses (Open Access)

Aneuploid epithelial cells are common in breast cancer, however their presence in normal breast tissues is not well understood. To address this question, we applied single cell DNA sequencing to profile copy number alterations (CNAs) in 83,206 epithelial cells from breast tissues of 49 healthy women and single cell DNA&ATAC co-assays to 19 women. Our data shows that all women harbored rare aneuploid epithelial cells (median 3.19%) that increased with age. Many aneuploid epithelial cells (median 82.22%) in normal breast tissues underwent clonal expansions and harbored CNAs reminiscent of invasive breast cancers (gains of 1q, losses of 10q, 16q and …

Quantifying Effects Of Partial Genetic Backgrounds To Decode Genetic Drivers Of Clinical Phenotypes, Rini Pauly

All Dissertations

Understanding partial genetic backgrounds illuminates the genetic architecture of complex traits and diseases, revealing how diverse genetic backgrounds contribute to phenotypic diversity. With this approach we could advance personalized medicine by identifying population-specific variants affecting drug metabolism, tailoring medical treatments to individual genetic profiles. Additionally, it offers evolutionary insights into human history, shedding light on past migrations and the spread of genetic traits. This research leverages cutting-edge statistical genetics techniques and novel machine learning approaches to efficiently analyze extensive population genomic datasets, distilling complex admixture signals into meaningful genetic markers.

The study introduces Admix-AI, an innovative convolutional neural network-based tool …

Dynamic Dysregulation Of Retrotransposons In Neurodegenerative Diseases At The Single-Cell Level\, Wankun Deng, Citu Citu, Andi Liu, Zhongming Zhao

Faculty, Staff and Student Publications

Retrotransposable elements (RTEs) are common mobile genetic elements comprising ∼42% of the human genome. RTEs play critical roles in gene regulation and function, but how they are specifically involved in complex diseases is largely unknown. Here, we investigate the cellular heterogeneity of RTEs using 12 single-cell transcriptome profiles covering three neurodegenerative diseases, Alzheimer's disease (AD), Parkinson's disease, and multiple sclerosis. We identify cell type marker RTEs in neurons, astrocytes, oligodendrocytes, and oligodendrocyte precursor cells that are related to these diseases. The differential expression analysis reveals the landscape of dysregulated RTE expression, especially L1s, in excitatory neurons of multiple neurodegenerative diseases. …

The Impact Of Temperature And Humidity On The Transcriptome Of Symbiochloris Reticulata In Relation To Lobaria Pulmonaria’S Genepools, Ioana Violeta Ardelean, Christoph Scheidegger, Mihai Miclaus

FRONTIERS UNBOUND: Exploring Extreme Environments

No abstract provided.

The Influence Of Environmental Change On Genetic Diversity Across Spatial And Taxonomic Scales, Connor M. French

Dissertations, Theses, and Capstone Projects

The spatial distribution of genetic diversity is of interest to biodiversity scientists and conservationists and is a fundamental metric of biodiversity. Genetic diversity patterns across spatial and taxonomic scales contain information about population and assemblage dynamics that can convey their resilience to environmental change. Ectotherms are especially linked to their environments and may be especially sensitive to fluctuations in the environment over time. Herein, I investigate global and regional patterns of genetic diversity in two groups of ectotherms, insects and lizards, to understand the relationship between environmental change and genetic diversity, from populations to assemblages. Overall, my research aims to …

Whole Genome And Reverse Protein Phase Array Landscapes Of Patient Derived Osteosarcoma Xenograft Models, Chia-Chin Wu, Licai Huang, Zhongting Zhang, Zhenlin Ju, Xingzhi Song, E Anders Kolb, Wendong Zhang, Jonathan Gill, Min Ha, Malcolm A Smith, Peter Houghton, Christopher L Morton, Raushan Kurmasheva, John Maris, Yael Mosse, Yiling Lu, Richard Gorlick, P Andrew Futreal, Hannah C Beird

Faculty, Staff and Student Publications

Osteosarcoma is the most common primary bone malignancy in children and young adults, and it has few treatment options. As a result, there has been little improvement in survival outcomes in the past few decades. The need for models to test novel therapies is especially great in this disease since it is both rare and does not respond to most therapies. To address this, an NCI-funded consortium has characterized and utilized a panel of patient-derived xenograft models of osteosarcoma for drug testing. The exomes, transcriptomes, and copy number landscapes of these models have been presented previously. This study now adds …

3d Chromatin Architecture, Brd4, And Mediator Have Distinct Roles In Regulating Genome-Wide Transcriptional Bursting And Gene Network, Pawel Trzaskoma, Seolkyoung Jung, Aleksandra Pękowska, Christopher H Bohrer, Xiang Wang, Faiza Naz, Stefania Dell'orso, Wendy D Dubois, Ana Olivera, Supriya V Vartak, Yongbing Zhao, Subhashree Nayak, Andrew Overmiller, Maria I Morasso, Vittorio Sartorelli, Daniel R Larson, Carson C Chow, Rafael Casellas, John J O'Shea

Faculty, Staff and Student Publications

Discontinuous transcription is evolutionarily conserved and a fundamental feature of gene regulation; yet, the exact mechanisms underlying transcriptional bursting are unresolved. Analyses of bursting transcriptome-wide have focused on the role of cis-regulatory elements, but other factors that regulate this process remain elusive. We applied mathematical modeling to single-cell RNA sequencing data to infer bursting dynamics transcriptome-wide under multiple conditions to identify possible molecular mechanisms. We found that Mediator complex subunit 26 (MED26) primarily regulates frequency, MYC regulates burst size, while cohesin and Bromodomain-containing protein 4 (BRD4) can modulate both. Despite comparable effects on RNA levels among these perturbations, acute depletion …

Identifying Genes Linked To Variation In Metabolic And Whole Plant Phenotypes Using Data From Genome Resequencing, Transcriptomics, And Metabolic Profiling Of A Field-Grown Maize Diversity Panel, Ramesh Kanna Mathivanan

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Maize metabolism is highly complex and influenced by genetic variation, yet the specific genes contributing to this variation and their links to non-metabolic traits remain less understood. To address this knowledge gap, we identified genes involved in maize metabolic variation and linked them to non-metabolic traits. We utilized a quadruplicate dataset of whole genome resequencing, transcriptomic, metabolic, and whole plant phenotype data from a single common field experiment of 660 diverse maize inbred lines. Leaf samples were collected shortly before flowering and analyzed using GC-MS for 26 metabolites. A Resampling Model Inclusion Probability Genome-Wide Association Study (RMIPGWAS) of approximately 2.6 …

Uncovering The Hidden Diversity Of Antibody Heavy Chains And Their Implications For Autoantibody Mediated Disease., Easton Earl Ford

Electronic Theses and Dissertations

Understanding the diversity of antibody (IG) molecules at the DNA and RNA level is imperative for understanding immunological processes and disease. Much of the work to uncover IG diversity has been focused on diversity in the variable region of the IG molecule which is crucial for antigen binding. However, the diversity of the constant region responsible for the functions of IG has largely been ignored in the field of immunogenetics. The work presented in this thesis challenges the dogma that the constant region is invariant in terms of genetic diversity. In this thesis we present the development of a long-read …

Crispr-Cas9 And Cas12a Target Site Richness Reflects Genomic Diversity In Natural Populations Of Anopheles Gambiae And Aedes Aegypti Mosquitoes, Travis C Collier, Yoosook Lee, Derrick K Mathias, Víctor López Del Amo

Faculty, Staff and Student Publications

Due to limitations in conventional disease vector control strategies including the rise of insecticide resistance in natural populations of mosquitoes, genetic control strategies using CRISPR gene drive systems have been under serious consideration. The identification of CRISPR target sites in mosquito populations is a key aspect for developing efficient genetic vector control strategies. While genome-wide Cas9 target sites have been explored in mosquitoes, a precise evaluation of target sites focused on coding sequence (CDS) is lacking. Additionally, target site polymorphisms have not been characterized for other nucleases such as Cas12a, which require a different DNA recognition site (PAM) and would …

Conservation Genomic Investigation Of A Threatened Trout Species Endemic To The Gila River, David Thomas Camak

Biology ETDs

Climate change is a looming threat to the persistence of species, especially aquatic, imperiled species. Species native to desert streams are at a particular disadvantage, as many species already face drought, floods, wildfires, and threats from nonnative species, all of which are thought to be exacerbated by climate change. Species such as the threatened Gila Trout (Oncorhynchus gilae) already have small ranges and persist in fragmented and isolated habitats that limits gene flow between populations. Therefore, it is important to understand the current genomic status of such populations to be able to predict the future effects of climate …

Discovery Of Runs-Of-Homozygosity Diplotype Clusters And Their Associations With Diseases In Uk Biobank, Ardalan Naseri, Degui Zhi, Shaojie Zhang

Faculty, Staff and Student Publications

Runs-of-homozygosity (ROH) segments, contiguous homozygous regions in a genome were traditionally linked to families and inbred populations. However, a growing literature suggests that ROHs are ubiquitous in outbred populations. Still, most existing genetic studies of ROH in populations are limited to aggregated ROH content across the genome, which does not offer the resolution for mapping causal loci. This limitation is mainly due to a lack of methods for the efficient identification of shared ROH diplotypes. Here, we present a new method, ROH-DICE (runs-of-homozygous diplotype cluster enumerator), to find large ROH diplotype clusters, sufficiently long ROHs shared by a sufficient number …

Maldi Imaging Mass Spectrometry Visualizes The Distribution Of Antidepressant Duloxetine And Its Major Metabolites In Mouse Brain, Liver, Kidney, And Spleen Tissues, Saleh M Khalil, Xuan Qin, John M Hakenjos, Jian Wang, Zhaoyong Hu, Xinli Liu, Jin Wang, Mirjana Maletic-Savatic, Kevin R Mackenzie, Martin M Matzuk, Feng Li

Faculty, Staff and Student Publications

Imaging mass spectrometry (IMS) is a powerful tool for mapping the spatial distribution of unlabeled drugs and metabolites that may find application in assessing drug delivery, explaining drug efficacy, and identifying potential toxicity. This study focuses on determining the spatial distribution of the antidepressant duloxetine, which is widely prescribed despite common adverse effects (liver injury, constant headaches) whose mechanisms are not fully understood. We used high-resolution IMS with matrix-assisted laser desorption/ionization to examine the distribution of duloxetine and its major metabolites in four mouse organs where it may contribute to efficacy or toxicity: brain, liver, kidney, and spleen. In none …

Effects Of Protein-Enriched Nutritional Support On Skeletal Muscle Mass And Rehabilitative Outcomes In Brain Tumor Patients: A Randomized Controlled Trial, Kye Hee Cho, Eun Young Han, Min Kyu Jung, Chang Moo Kang, Ji Cheol Shin, Sang Hee Im

Faculty, Staff and Student Publications

Patients with brain tumors require extensive and prolonged rehabilitation efforts as they suffer from lesion-induced motor weakness as well as treatment-related side effects, often leading to a significant decline in function. Protein supplements have shown positive effects on promoting muscle strength and physical performance in various tumor etiologies. However, reports on their effects specifically in brain tumor patients remain scarce. This study aims to investigate the feasibility and efficacy of protein supplements in enhancing rehabilitative outcomes via muscle strengthening and functional gain in brain tumor patients with neurological demise. Sixty brain tumor patients were randomly assigned to either a protein …

Evolution And Adaptation To Temperature In Thermotogota, Anne Amelia Farrell

Dartmouth College Ph.D Dissertations

Life thrives across incredibly diverse environmental conditions, yet most organisms are restricted to growing within a narrow range around their optimum growth temperature (OGT). The evolutionary events leading to changes in OGT are poorly understood, and it is uncertain if specific genes are required to thrive at a particular temperature. The bacterial phylum Thermotogota is an excellent model for the evolution of OGT. It comprises mesophilic, thermophilic, and hyperthermophilic members that collectively grow between 20°C and 90°C.

In this work, I analyze the history of OGT in the Thermotogota phylum and show how horizontal gene transfer contributes to the evolution …

Omani Camels From A Cultural And Genomics Perspective, Al Muatasim Al Zadjali

Electronic Theses and Dissertations

The Dromedarian camel, Camelus dromedarius, is native to the Arabian Peninsula, including the Sultanate of Oman. These camels are used for food, milk, as well as show and racing competitions. Despite their economic and cultural importance research on camels in Oman is limited. The goal of this study was to examine their genomic variation, relationship with camels in other parts of the Arabian Peninsula, and to determine if selective breeding has led to the establishment of distinct breeds in Oman. Information was compiled from multiple sources to produce a comprehensive review on the breeding, management, economic and cultural use, …

Crossing The Ocean: The Importance Of Gene Flow In Island Evolution, Ethan F. Gyllenhaal

Biology ETDs

Islands have long been a critical arena for the development of ecological and evolutionary theory, particular due to persistent open-water gaps between them. In this dissertation I demonstrates how these caps are permeable, which can be leveraged to understand evolution on islands and more broadly. The first chapter develops this connection between ongoing, overwater gene flow and island biogeographic theory, and tests it on an archipelago species. The second take a three-pronged approach in demonstrating how over-water gene flow can bias phylogenetic inference, and how many phylogeographic metrics in islands are likely shaped by long-term gene flow. The final two …

Cis-Regulatory Mechanisms Through Stages Of Erythroid Regenration, Yichao Zhou

Theses & Dissertations

Produced by steady state erythropoiesis, erythrocytes serve as vital regulators of metabolism and life by delivering oxygen to all the cells and tissues. Under acute anemia, steady state erythropoiesis is not sufficient to produce enough erythrocytes, leading to distinct mechanisms needed to regenerate large numbers of mature erythrocytes rapidly. Erythroid regeneration occurs in four stages: activation, expansion and differentiation, resolution, and post-resolution, according to the dynamics of erythrocyte numbers and progenitor activity. Erythroid regeneration throughout this timeline requires some critical extracellular cues, but the intrinsic molecular mechanisms needed to accelerate and decelerate the activity of erythroid progenitors in anemia and …

Uncovering Novel Small Regulatory Rna In Protostome, Sweta Khanal

Dissertations

Small RNAs play pivotal roles in post-transcriptional gene regulation across diverse phylum of protostomes. In this study, we investigate the functional significance of atypical miRNAs, mirtron miR-1017 in Drosophila. Through ectopic expression in neuronal cells, we demonstrate that miR-1017 extends lifespan by targeting its host transcript, acetylcholine receptor Dα2, and influencing its splicing. This novel trans-regulatory function suggests a mechanism for mirtron evolution, highlighting the interplay between splicing and post-transcriptional regulation. Additionally, we profile small RNA populations in the polychaete developmental model Capitella teleta, shedding light on the small RNA landscape in annelid worms. Our analysis reveals a rich …

Archaeal Diversity In The Anna's Hummingbird Microbiome, Lauren E. Chance

Honors Scholar Theses

The microbial communities that are present in and on vertebrates are collectively called the microbiome. The composition of a microbiome is dependent upon the host, the environment, and evolution. There has been extensive research on the bacterial composition of host-associated microbiomes, however, there has been much less work on the archaeal composition of host-associated microbiomes. Archaea have previously been assumed to primarily exist in extreme environments, but this may not be true and has been influenced by their generally low abundance and methodological difficulties in detection. It is possible they are consistent members of diverse host-associated microbiomes.

Archaea-specific PCR primers …

Mismatch Repair Deficient Neoantigen And Associated Circulating T-Cell Receptor Repertoires In Lynch Syndrome, Ana Bolivar

Dissertations and Theses (Open Access)

Lynch Syndrome (LS) is the most common inherited colorectal cancer (CRC) syndrome. It constitutes the perfect model to understand DNA mismatch repair deficient (MMRd) carcinogenesis, which underlies 15% of early-stage CRC. LS patients develop MMRd tumors with high loads of shared neoantigens (neoAgs), which are recognized by the immune system. Previous research has concentrated on discovering neoAgs and their potential as targets for vaccines in LS patients. However, these studies have primarily identified shared neoAgs from cancers, lacking detailed information on targetable neoAgs present in precancerous lesions. Understanding this landscape of pre-cancer derived neoAgs is crucial for intercepting cancer development …

Genomic Characterization Of Enterococcus Spp Infecting Chicken Embryo, Aishat Olaoluwa Lawal

Graduate Theses and Dissertations

Chicken embryo mortality has been attributed to bacterial infections and can lead to a decline in hatchability, posing potential losses in the broiler industry. This study aims to investigate the vertical transmission of specific bacterial pathogens from breeder hens to subsequent broiler flocks through MGEs and their association with host specificity. In our sampling of 360 eggs from a broiler flock, we isolated various Enterococcus species, including E. gallinarum and E. faecalis, from incubated egg yolks or aborted embryos. E. avium was found in unincubated bad yolks. Other species like Streptococcus, Lactobacillus, and Bacillus were observed but presumed to be …

The In4mer Crispr/Cas12a Multiplex Knockout Platform And Its Applications, Nazanin Esmaeili Anvar

Dissertations and Theses (Open Access)

Discovering synthetic lethal interactions between genes holds the key to uncovering cancer vulnerabilities, enabling the development of more effective drugs for patients. However, identifying these vulnerabilities in the complex genome of human, which comprises thousands of genes, poses a significant challenge. One alternative approach to investigate these interactions involves exploring enriched sources of synthetic lethal interactions, such as paralog pairs. In recent years, a couple of studies have conducted dual-gene knockout experiments on paralog pairs using different approaches to identify synthetic lethal interactions. In this study, we conducted a meta-analysis of CRISPR genetic interaction screens. We identified a candidate set …

The Genomics Of Champ1: Insights Into Their Cell-Type Specificity And Developmental Trajectories, Zoe Marie Van Caugherty

MUSC Theses and Dissertations

Chromosome alignment maintaining phosphoprotein 1(CHAMP1) is a gene that encodes a zinc finger protein that is involved in in the maintenance of kinetochore-microtubule attachment and regulating chromosome segregation in mitosis. (Itoh et al., 2011) CHAMP1 mutations have been shown to be major risk factors for neurodevelopmental disorders (NDDs) and autism spectrum disorder (ASD).(Asakura et al., 2021; Isidor et al., 2016; Levy et al., 2022) Although there is information on the link between CHAMP1 mutations and NDD, the role of CHAMP1 in regulating processes of human cortical development, namely, neurogenesis, proliferation, and electrophysiological properties of newly born neurons, is unknown. This …

Edna Metabarcoding And The Construction Of Primers For The Identification Of Gulf Of Mexico Elasmobranchs And Selachii, Isabella Lima

Honors Projects

eDNA, or environmental DNA, is found free-existing in any environment. It can be extracted from its environment and used to identify organisms that were recently in the area. In recent years, eDNA metabarcoding has been used to help examine communities for overall species presence and biodiversity. This capstone sought to create a mock proposal for an eDNA survey of Gulf of Mexico elasmobranch and Selachii species due to their overall decline in numbers. Additionally, general and discriminatory PCR primers were created in-silico and assessed for initial quality. This capstone documents the feasibility of an eDNA study, constructing the necessary primers, …