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Coevolution Of Hosts And Pathogens In The Presence Of Multiple Types Of Hosts, Evan J. Mitchell

Electronic Thesis and Dissertation Repository

How will hosts and pathogens coevolve in response to multiple types of hosts? I study this question from three different perspectives. First, I model a scenario in which hosts are categorized as female or male. Hosts invest resources in maintaining their immune system at a cost to their reproductive success, while pathogens face a trade-off between transmission and duration of infection. Importantly, female hosts are also able to vertically transmit an infection to their newborn offspring. The main result is that as the rate of vertical transmission increases, female hosts will have a greater incentive to pay the cost to …

Rates And Patterns Of Indels In Hiv-1 Gp120 Within And Among Hosts, John Lawrence Palmer

Electronic Thesis and Dissertation Repository

Insertions and deletions (indels) in the HIV-1 gp120 variable loops modulate sensitivity to neutralizing antibodies and are therefore implicated in HIV-1 immune escape. However, the rates and characteristics of variable loop indels have not been investigated within hosts. Here, I report a within-host phylogenetic analysis of gp120 variable loop indels, with mentions to my preceding study on these indels among hosts.

We processed longitudinally-sampled gp120 sequences collected from a public database (n = 11,265) and the Novitsky Lab (n=2,541). I generated time-scaled within-host phylogenies using BEAST, extracted indels by reconstructing ancestral sequences in Historian, and estimated variable loop indel rates …

Characterizing Mekk1: Candidate Behavioural Isolation Gene, Caryn Dooner

Electronic Thesis and Dissertation Repository

Behavioural isolation can occur due to divergence in aspects of courtship and mating, and can contribute to reproductive isolation. The purpose of this study is to determine how a gene, Mekk1, contributes to female rejection behaviour between D. melanogaster and D. simulans. Unique polymorphisms were identified within D. simulans Mekk1 that could contribute to behaviour, most of which are non-coding. Both transcripts of Mekk1 appear to be expressed at similar levels in D. simulans and D. melanogaster. These data also indicate that Mekk1 may be expressed in a specific region of the brain called the mushroom body, …

The Genetic And Environmental Basis For Chc Biosynthesis In Drosophila, Heather Ke Ward

Electronic Thesis and Dissertation Repository

Cuticular hydrocarbons (CHCs) are produced by insects and primarily used to prevent desiccation. In Drosophila, certain compounds have secondary roles as infochemicals that may act during courtship to influence mate choice. Certain CHCs may stimulate courtship with heterospecifics or act to repel conspecifics. The CHC profile produced by an individual is the result of the interaction between its genetic background and the environment, though the genes that underlie species differences in CHC production and how the environment can modulate the abundance of individual compounds within a species is not well known. Here, candidate gene CG5946 was found to be …

First Major Appearance Of Brachiopod-Dominated Benthic Shelly Communities In The Reef Ecosystem During The Early Silurian, Cale A.C. Gushulak

Electronic Thesis and Dissertation Repository

The early Silurian reefs of the Attawapiskat Formation in the Hudson Bay Basin preserved the oldest record of major invasion of the coral-stromatoporoid skeletal reefs by brachiopods and other marine shelly benthos, providing an excellent opportunity for studying the early evolution, functional morphology, and community organization of the rich and diverse reef-dwelling brachiopods. Biometric and multivariate analysis demonstrate that the reef-dwelling Pentameroides septentrionalis evolved from the level-bottom-dwelling Pentameroides subrectus to develop a larger and more globular shell. The reef-dwelling brachiopods in the paleoequatorial Hudson Bay Basin were more diverse than contemporaneous higher latitude reef-dwelling brachiopod faunas, with ten distinct …

Evaluation Of Mertk Evolution And Efferocytosis Signalling, Amanda L. Evans

Electronic Thesis and Dissertation Repository

The TAM (TYRO3, AXL, and MERTK) family of receptor tyrosine kinases allow phagocytes to engage in the phagocytic removal of apoptotic cells. Although all three members of the TAM family are structurally homologous and function in a similar fashion, both human genome-wide association studies and knockout mice models have demonstrated that MERTK is the critical member of the TAM family for maintaining homeostasis. In this thesis, an evolutionary analysis was used to provide insight into the function of MERTK. Selection analysis in primates unexpectedly revealed a high degree of recent positive selection in MERTK’s signal peptide and transmembrane domain, …

The Evolution Of Kin Recognition, Timothy Ja Hain

Electronic Thesis and Dissertation Repository

The discovery that many animals are promiscuous has challenged the importance of Hamilton’s Rule because it reduces the net benefits of helping nestmates. To resolve this challenge, biologists have investigated animals’ abilities to determine degrees of relatedness among individuals using kin recognition mechanisms. I conducted a literature review and found that most animals use one of two mechanisms: “familiarity” whereby kin are remembered from interactions early in life, such as in a nest, or “phenotype matching” whereby putative kin are compared to a template of what kin should look, smell, or sound like based on relatives encountered during early life …

Evolutionary And In Silico Analysis Of The Antiviral Trim22 Gene, Jenna Kelly

Electronic Thesis and Dissertation Repository

Tripartite motif protein 22 (TRIM22) is an evolutionarily ancient interferon-induced protein that been shown to potently inhibit human immunodeficiency virus (HIV), hepatitis B virus (HBV), and influenza A virus (IAV) replication. Altered TRIM22 expression levels have also been linked to autoimmune disease, cancer, and cellular proliferation. Despite its important role in a number of biological processes, the factors that influence TRIM22 expression and/or antiviral activity remain largely unknown. To identify key functional sites in TRIM22, we performed extensive evolutionary and in silico analyses on the TRIM22 coding region. These tools allowed us to pinpoint multiple sites in TRIM22 that have …