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- Title
- Assessing the viability of the shifting balance process
- Creator
- Moore, Francis B.,-G
- Date
- 1996
- Collection
- Electronic Theses & Dissertations
- Title
- Natural history and conservation genetics of the federally endangered Mitchell's satyr butterfly, Neonympha mitchellii mitchellii
- Creator
- Hamm, Christopher Alan
- Date
- 2012
- Collection
- Electronic Theses & Dissertations
- Description
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The Mitchell's satyr butterfly, Neonympha mitchellii mitchellii, is a federally endangered species with protected populations found in Michigan, Indiana, and wherever else populations may be discovered. The conservation status of the Mitchell's satyr began to be called into question when populations of a phenotypically similar butterfly were discovered in the eastern United States. It is unclear if these recently discovered populations are N. m. mitchellii and thus warrant protection. In...
Show moreThe Mitchell's satyr butterfly, Neonympha mitchellii mitchellii, is a federally endangered species with protected populations found in Michigan, Indiana, and wherever else populations may be discovered. The conservation status of the Mitchell's satyr began to be called into question when populations of a phenotypically similar butterfly were discovered in the eastern United States. It is unclear if these recently discovered populations are N. m. mitchellii and thus warrant protection. In order to clarify the conservation status of the Mithcell's satyr I first acquired sample sizes large enough for population genetic analysis I developed a method of non-lethal sampling that has no detectable effect on the survival of the butterfly. I then traveled to all regions in which N. mitchellii is known to be extant and collected genetic samples. Using a variety of population genetic techniques I demonstrated that the federally protected populations in Michigan and Indiana are genetically distinct from the recently discovered populations in the southern US. I also detected the presence of the reproductive endosymbiotic bacterium Wolbachia, and surveyed addition Lepidoptera of conservation concern. This survey revealed that Wolbachia is a real concern for conservation managers and should be addressed in management plans. Finally, I examined the variation in wing patterns among Neonympha taxa using geometric morphometrics and multivariate statistics. This methodology allows researchers to empirically examine qualitative traits by placing landmarks at homologous position and quantify the variation among taxon. Analysis of wing patterns revealed that the endangered taxa could be clearly and consistently distinguished from congeners. I conclude this dissertation with an outlook for the Mitchell's satyr and a call to action for the protection and recovery of this endangered species.
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- Title
- Space-time modeling and application to emerging infectious diseases
- Creator
- Lee, Cheng-Yu
- Date
- 2005
- Collection
- Electronic Theses & Dissertations
- Title
- Characterization, population genetics and management of Pythium spp. from floriculture crops in Michigan
- Creator
- Del Castillo-Munera, Johanna
- Date
- 2015
- Collection
- Electronic Theses & Dissertations
- Description
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Michigan ranks third in the U.S. for the wholesale value of floriculture products, with an estimated value of $375.7 million. Seedling damping-off, and root and crown rot are commonly incited by Pythium spp. and are important problems for greenhouse growers. Pythium spp. associated with Michigan's floriculture crops were characterized as a means to improve current management strategies. During 2011 and 2012, symptomatic potted poinsettias were sampled from nine greenhouses in Kent, Kalamazoo...
Show moreMichigan ranks third in the U.S. for the wholesale value of floriculture products, with an estimated value of $375.7 million. Seedling damping-off, and root and crown rot are commonly incited by Pythium spp. and are important problems for greenhouse growers. Pythium spp. associated with Michigan's floriculture crops were characterized as a means to improve current management strategies. During 2011 and 2012, symptomatic potted poinsettias were sampled from nine greenhouses in Kent, Kalamazoo and Wayne counties. The following year, from the same three counties, symptomatic geranium and snapdragon bedding plants were sampled from 11 greenhouses. Isolates were confirmed to be Pythium spp. via morphology and sequencing of the ITS region. A total of 1,014 Pythium spp. isolates were obtained; P. irregulare, P. ultimum, and P. aphanidermatum were most prevalent. A subset of isolates was chosen for pathogenicity and mefenoxam sensitivity testing. Most of the Pythium species were virulent to germinating geranium seeds. This study suggests that mefenoxam may not be effective to control P. ultimum or P. cylindrosporum. To understand the population dynamics of the P. ultimum collection simple sequence repeats (SSRs) were developed using P. ultimum transcriptome to address the population structure. After screening in-silico SSR markers, six SSRs were selected based on their polymorphism on a sub set of P. ultimum isolates. A total of 166 P. ultimum isolates were analyzed using the six fluorescent-labeled SSRs. The average genotypic diversity (0.938), evenness (0.56), and the recovery of 12 major clones, out of the 64 multilocus genotypes obtained may suggest that P. ultimum is not a recent introduction into Michigan greenhouses. Analysis revealed a clonal population with limited differentiation among seasons, hosts and counties sampled. To develop strategies that limit Pythium root rot on geranium and snapdragon, greenhouse trials were conducted to test plant protectants and screen cultivars for resistance. Seven fungicides and two biological control agents were evaluated on plants inoculated with P. aphanidermatum, P. irregulare or P. ultimum. The AUDPC values differed significantly (P<0.001) among Pythium spp. and treatments. Mefenoxam and Streptomyces lydicus WYEC108 effectively controlled root rot on geranium. For snapdragon, treatment efficacy varied depending on the Pythium sp. When eleven geranium cultivars, and twelve snapdragon cultivars were inoculated with P. aphanidermatum or P. irregulare, none were completely resistant. However, geranium `Nano White Hybrid' and `Bulls Eye Cherry' and snapdragon `Twinny White' and `Candy Showers Yellow' were least susceptible. Integrating effective fungicides with less susceptible cultivars can limit disease caused by Pythium spp.
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- Title
- Lack of cryptic reproduction isolation between Papilio canadensis and Papilio glaucus, and population genetics near their hybrid zone
- Creator
- Stump, Aram Daniel
- Date
- 2000
- Collection
- Electronic Theses & Dissertations
- Title
- The evolution of complexity and robustness in small populations
- Creator
- LaBar, Thomas
- Date
- 2018
- Collection
- Electronic Theses & Dissertations
- Description
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"A central goal of evolutionary biology is to understand a population's evolutionary trajectory from fundamental population-level characteristics. The mathematical framework of population genetics provides the tools to make these predictions. And while population genetics provides a well-studied framework to understand how adaptation and neutral evolution quantitatively alter population fitness, less attention has been paid to using population genetics to predict qualitative evolutionary...
Show more"A central goal of evolutionary biology is to understand a population's evolutionary trajectory from fundamental population-level characteristics. The mathematical framework of population genetics provides the tools to make these predictions. And while population genetics provides a well-studied framework to understand how adaptation and neutral evolution quantitatively alter population fitness, less attention has been paid to using population genetics to predict qualitative evolutionary outcomes. For instance, do different populations evolve alternative genetic mechanisms to encode similar phenotypic traits, and if so, which processes lead to these differences? This dissertation investigates the role of population size in altering the qualitative outcome of evolution. It is difficult to experimentally investigate qualitative evolutionary outcomes, especially in small populations, due to the time required for novel evolutionary features to appear. To get around this constraint, I use digital experimental evolution. While digital evolution experiments lack aspects of biological realism, in some regards they are the only methodology that can approach the complexity of biological systems while maintaining the ease of analysis present in mathematical models. Digital evolution experiments can never prove that certain evolutionary trajectories occur in biological populations, but they can suggest hypotheses to test in more realistic model systems. First, I explore the role of population size in determining the evolution of both genomic and phenotypic complexity. Previous hypotheses have argued that small population size may lead to increases in complexity and I test aspects of those hypotheses here. Second, I introduce the novel concept of 'drift robustness' and argue that drift robustness is a strong factor in the evolution of small populations. Finally, I end with a project on the role of genome size in enhancing the extinction risk of small populations. I conclude with a broader discussion of the consequences of this research, some limitations of the results, and some ideas for future research."--Page ii.
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- Title
- Population genetic analyses of Salmonella enterica serovar enteritidis and Escherichia coli from biotic and abiotic sources
- Creator
- Walk, Seth Taylor
- Date
- 2007
- Collection
- Electronic Theses & Dissertations
- Title
- Statistical methods for identifying genetic associations
- Creator
- Lan Tong
- Date
- 2005
- Collection
- Electronic Theses & Dissertations