Life Sciences Commons^™

Metagenomic Identification And Classification Of The Mercury-Methylating Gene Hgca In Response To Water Table And Plant Functional Group Manipulations In Peat Soil, Madeline Peterson

Dissertations, Master's Theses and Master's Reports

Methyl-mercury (MeHg) is a potent neurotoxin that threatens the health of humans and wildlife alike. Climate warming threatens to shift regional precipitation and climate regimes in peatland environments, which could destabilize northern peatlands and accelerate both Hg release from soil and MeHg production. Peatlands are among the leading hotspots for MeHg, yet little is known about the community composition or functional relationship of mercury-methylating microbes in response to varying environmental conditions. The recognized mercury-methylating genes responsible for this activity are the obligatory gene pair hgcA and hgcB. Metagenomic data from the full-factorial peatland mesocosm experiment PEATcosm was obtained to …

Statistical Methods In Genetic Studies, Cheng Gao

Dissertations, Master's Theses and Master's Reports

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

In Chapter 1, we proposed a new method, called MF-TOWmuT, for genome-wide association studies with multiple genetic variants and multiple phenotypes using family samples. MF-TOWmuT uses kinship matrix to account for sample relatedness. It is worth mentioning that in simulations, we considered hidden polygenic effects and varied the proportion of variance contributed by it to generate phenotypes. Simulation studies show that MF-TOWmuT can preserve the type I error rates and is more powerful than several existing methods in different simulation scenarios, MFTOWmuT is also quite …

The Effect Of Nutrition On Longevity And Fertility In Diverse Drosophila: A Tor-Mediated Process, Tessa E. Steenwinkel

Dissertations, Master's Theses and Master's Reports

Nutrition and growth are strongly linked, but not much is known about how nutrition leads to growth. To understand the connection between nutrition through diet, growth and/or proliferation, we need to study the phenotypes resulting from the activation and inhibition of central metabolic pathways. Here I use the model organism Drosophila melanogaster (D. mel.) and three non-model Drosophila species with different dietary needs, Drosophila guttifera (D. gut.), Drosophila deflecta (D. def.), and Drosophila tripunctata (D. tri.), to study the effects of dietary amino acid availability in these diverse flies on fecundity and …

Functional Genetic Approaches To Provide Evidence For The Role Of Toolkit Genes In The Evolution Of Complex Color Patterns In Drosophila Guttifera, Mujeeb Olushola Shittu

Dissertations, Master's Theses and Master's Reports

Toolkit genes are set of genes that orchestrate the development of basic body plan of animals, and they are highly conserved in all animals. The co-option of the toolkit genes into the pigmentation pathway has led to the evolution of novel species. This study focuses on understanding how the complex color patterns in animals develop by using the Drosophila species in the quinaria group as models. We developed an mRNA in situ hybridization (ISH) protocol, which allowed us to study gene expression patterns in the abdomen of developing pupae of non-model Drosophila species (Chapter 2). Through ISH, we found that …

Applications Of Machine Learning In Microbial Forensics, Ryan B. Ghannam

Dissertations, Master's Theses and Master's Reports

Microbial ecosystems are complex, with hundreds of members interacting with each other and the environment. The intricate and hidden behaviors underlying these interactions make research questions challenging – but can be better understood through machine learning. However, most machine learning that is used in microbiome work is a black box form of investigation, where accurate predictions can be made, but the inner logic behind what is driving prediction is hidden behind nontransparent layers of complexity.

Accordingly, the goal of this dissertation is to provide an interpretable and in-depth machine learning approach to investigate microbial biogeography and to use micro-organisms as …

Construction And Analysis Of Genetic Regulatory Networks With Rna-Seq Data From Arabidopsis Thaliana, Tessa Kriz

Dissertations, Master's Theses and Master's Reports

Reconstruction of gene regulatory networks (GRNs) is a fundamental aspect of genetic engineering and provides a deeper understanding of the biological processes of an organism. Two methods were implemented to reconstruct the gene regulatory networks of Arabidopsis thaliana under two treatments: methyl jasmonate (MeJa) and salicylic acid (SA). The Joint Reconstruction of multiple Gene Regulatory Networks (JRmGRN) method was utilized to construct a joint network for identifying hub genes common to both conditions in addition to networks specific to each condition. The Differential Network Analysis with False Discover Rate Control method constructed a network of connections unique to only one …