Life Sciences Commons^™

Neuroanatomical Characterization Of Fruitless P2 Neurons And Assessment Of Their Role In Female Mate Receptivity, William Yeung

Electronic Thesis and Dissertation Repository

In behaviourally isolated species, preferential mate choice for conspecifics over heterospecifics is a primary isolating barrier for reducing interspecific gene flow. Drosophila males court heterospecific females more frequently than females are sexually receptive to courting heterospecific males, emphasizing the importance of female mate preference in reproductive isolation. The neurogenetic bases of female mate preference have been elusive historically, but recent research identified the D. melanogaster fruitless (fru) P2 exon to influence both conspecific and heterospecific female receptivity. I have expanded on these findings by creating a transgenic line that expresses Gal4 under fru^P2 regulation. Driving a fluorescent …

Developing A Toolbox To Engineer Quantitative Trait Variation In Legume Species Using Crispr/Cas Technologies., Petar Miletic

Electronic Thesis and Dissertation Repository

The impact of intensive agriculture on the environment is immense. This is especially dire with regard to the natural nitrogen (N) cycle, where the human driven interference, primarily associated with industrial fertilization, has reached unsustainable levels. Unlike cereals, legumes, such as soybean, alfalfa and common bean, have the ability to use atmospheric nitrogen, which limits the need for industrial fertilization. A more wide-spread use of legumes could alleviate some of the negative impacts on the biogeochemical cycle while also providing a useful alternative to meat consumption, an important factor in sustainability. To reach this goal, further improvements of legume crops …

Improved Radiation Expression Profiling In Blood By Sequential Application Of Sensitive And Specific Gene Signatures, Eliseos J. Mucaki, Ben C. Shirley, Peter K. Rogan

Biochemistry Publications

Purpose. Combinations of expressed genes can discriminate radiation-exposed from normal control blood samples by machine learning based signatures (with 8 to 20% misclassification rates). These signatures can quantify therapeutically-relevant as well as accidental radiation exposures. The prodromal symptoms of Acute Radiation Syndrome (ARS) overlap those present in Influenza and Dengue Fever infections. Surprisingly, these human radiation signatures misclassified gene expression profiles of virally infected samples as false positive exposures. The present study investigates these and other confounders, and then mitigates their impact on signature accuracy.

Methods. This study investigated recall by previous and novel radiation signatures independently derived …

Establishment Of A Pesticide Resistance Monitoring Tool For The Two-Spotted Spider Mite, Tetranychus Urticae, Hanna Varonina

Electronic Thesis and Dissertation Repository

Two-spotted spider mite (TSSM), or Tetranychus urticae (Koch), is a major agriculture pest known for its rapid development of resistance to pesticides. The analysis of spider mites’ pesticide resistance demonstrated that resistance patterns and frequencies vary between T. urticae strains collected from different geographic locations and host plants. This research aims at characterization of pesticide resistance patterns in mite populations present in greenhouses in the Southwestern Ontario by identifying genetic and metabolic markers of their pesticide resistance. The establishment of these markers lays the basis for development of a pesticide resistance diagnostic tool that will enable prediction of population resistance …

The Role Of Pannexin 3 In Forced Exercise Bone Remodelling And Its Potential Implications For Osteoarthritis, Justin Tang

Undergraduate Student Research Internships Conference

Exercise such as running has been hypothesized to be a factor of osteoarthritis development. However, the relationship is unclear as differences in genetic backgrounds may influence the risk of osteoarthritis (OA). The gene Panx3 codes for the Pannexin 3 protein (PANX3), a mechanically sensitive channel that allows for the passage of various signalling molecules in both chondrocytes and osteoblasts (Boassa et al., 2007; Penuela et al., 2013; Zhang et al., 2021). We have previously shown PANX3 to be protective in traumatic osteoarthritis, however beneficial in age-induced osteoarthritis (Moon et al., 2021), suggesting that PANX3’s role in osteoarthritis development …

Fine-Scale Morphological Divergence Of Wing Trait Variables In Highly Fragmented Populations Of The Bog Copper Butterfly (Lycaena Epixanthe), Jessica L. T. Jeong

Undergraduate Student Research Internships Conference

Habitat fragmentation can adversely affect animal and plant species through subdividing their natural habitats into smaller, more isolated patches. Oftentimes, these isolated groups are subject to reduced dispersal and gene flow, leading to genetic divergence and, consequently, morphological divergence among populations. This study aims to quantify the morphological divergence of the bog copper butterfly, Lycaena epixanthe, between nine isolated bog sites in Algonquin Provincial Park, Ontario, via seven quantitative morphological traits in their wing pattern. Statistical analyses demonstrate significant differences in wing trait measurements between populations. As bog coppers are small, weak fliers with a strict host-plant dependency, it …

Functional Characterization Of Arogenate Dehydratase Isoforms In Soybean, Ramtin Sirjani

Electronic Thesis and Dissertation Repository

Phenylalanine flux is partitioned between phenylpropanoid and protein synthesis. The mechanisms behind the metabolic channeling of phenylalanine are largely unknown. Arogenate dehydratase (ADT) enzymes, which catalyze the last and rate-limiting step in the synthesis of phenylalanine in plants, have been shown to interact with the isoflavonoid metabolon in the cytosol. Cytosolic phenylalanine, however, can only be synthesized through prephenate dehydratase (PDT) activity. In this study, putative soybean ADTs (GmADTs) were characterized for their ADT and PDT activity. This was done using complementation assays with two different knockout yeast strains, aro8aro9 and pha2, which lack prephenate aminotransferase and PDT activity, …

Evaluation Of Two Mouse Models Of High Genetic Variation For Suitability To Test A Heterozygote Instability Hypothesis, Hailie Pavanel

Electronic Thesis and Dissertation Repository

Characterization of genetic variation underlying complex phenotypes is incomplete yet critical to understanding mutational mechanisms and phenotypes. Heterozygote Instability (HI) is a new, poorly understood source of mutations needing models for mechanistic study. Two models ideal for characterizing HI-associated mutational mechanisms are outbred mice and mouse basal cell carcinoma (BCC). Both have discontinuous landscapes of heterozygosity essential to assess HI-induced mutations. Here, heterozygosity and copy number variants (CNVs) in two outbred mouse stocks are characterized with 1690, and 3935 autosomal CNVs detected. A positive correlation exists between chromosomal heterozygosity and CNV occurrence (R² = 0.14 and 0.09), and 41 …

Genetic Approaches For The Study Of Complex Human Diseases, Julieta Lazarte

Electronic Thesis and Dissertation Repository

The field of human genetics has evolved from its initial narrow focus on single-gene Mendelian disorders, which largely affect children, to our current understanding that for most diseases there is continuum of rare to common variants which can exert a range of phenotypic effects. Despite advances in sequencing capabilities and our overall understanding of diseases, there remains a large proportion of heritability unexplained. Through the use of next-generation sequencing technologies and DNA microarray, I have explored a spectrum of genetic variations from rare, single and structural variants to common variants in individuals with i) “lone” atrial fibrillation; ii) familial hypercholesterolemia; …

Dynamics Of The Soil Microbiome In Ginseng Gardens, Megan E. Lambert

Electronic Thesis and Dissertation Repository

Ginseng Replant Disease (GRD) is a syndrome in which ginseng cannot be cultivated in soil previously used to grow ginseng. Since GRD can persist for decades, it severely impacts the Ontario ginseng industry. To better understand the origin of GRD, the impact of ginseng cultivation on the soil microbiome was investigated in bulk soil of three newly planted ginseng gardens in Ontario, from seeding through two years of cultivation. While specific trends in species richness, diversity and composition were unclear, PERMANOVA analyses confirmed that they changed over time. Known GRD-related pathogens, including Ilyonectria mors-panacis and Fusarium oxysporum, were detected in …

The Role Of Gsk3 Alpha And Beta In Embryonic Craniofacial Development, Harman Jassar

Electronic Thesis and Dissertation Repository

Background: The GSK-3 genes (Gsk3a and Gsk3b) have been known to affect many cellular processes and signaling pathways some of which are implicated in the growth and development of the craniofacial skeleton.

Aim: The purpose of this study was to assess the effect of chondrocyte-specific deletion of Gsk3a and Gsk3b on the size of the mandible and craniofacial skeleton in embryonic mice.

Materials & Methods: Mice were bred to generate cartilage-specific Gsk3a and Gsk3b KO mice. On embryonic day 18.5 (E18.5) the offspring were gathered by caesarian section. Whole mount skeletal staining was completed on the specimens using …