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Articles 1 - 17 of 17
Full-Text Articles in Genetics and Genomics
Nuclear Genome Size Diversity Of Marine Invertebrate Taxa Using Flow Cytometric Analysis, Kyle Roebuck
Nuclear Genome Size Diversity Of Marine Invertebrate Taxa Using Flow Cytometric Analysis, Kyle Roebuck
HCNSO Student Theses and Dissertations
Genomic analysis provides a substantial amount of information on evolutionary history, novel genes, transcriptomic expression and regulation in response to environmental stimuli, how efficiently organisms utilize their genome, and directional genome evolution. Genome size analysis serves as the first step in the sequencing process, because sequencing and annotation costs are directly correlated with genome size. Invertebrates represent the vast majority of faunal diversity on the planet, and, to a greater extent, the marine environment, although they are vastly understudied when compared to vertebrate genomes. Flow cytometry is a widely used, reliable, and accurate means of estimating genome sizes and has …
Systematics And Biogeography Of The Cortinarius Violaceus Group And Sequestrate Evolution In Cortinarius (Agaricales), Emma Harrower
Systematics And Biogeography Of The Cortinarius Violaceus Group And Sequestrate Evolution In Cortinarius (Agaricales), Emma Harrower
Doctoral Dissertations
Phylogenetics is a powerful tool used for illuminating the diversity of life on Earth, their evolution and their ecology. I created a multi-gene phylogenetic tree of Cortinarius section Cortinarius and uncovered five previously overlooked species, increasing the number of species in the section from seven to twelve. All members of the clade possess both cheilocystidia and pleurocystidia and possess a pigment known as (R)-39,49-dihydroxybphenylalanine. Ancestral state reconstruction estimated that the ancestral host was most likely an angiosperm, switching hosts when encountering novel host species in new lands, and only C. violaceus associating with the Pinaceae in North America. Biogeographic analysis …
Characterizing Mekk1: Candidate Behavioural Isolation Gene, Caryn Dooner
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, …
Detection, Diversity, And Evolution Of Fungal Nitric Oxide Reductases (P450nor), Steven Adam Higgins
Detection, Diversity, And Evolution Of Fungal Nitric Oxide Reductases (P450nor), Steven Adam Higgins
Doctoral Dissertations
Nitrous oxide (N2O) is a gas responsible for significant ozone layer depletion and contributes to greenhouse effects in Earth’s atmosphere. N2O is primarily generated by denitrification, whereby nitrate (NO3-) or nitrite (NO2-) is converted to gaseous N2O or N2. Teragram quantities of N2O are emitted annually from agricultural soils treated with nitrogenous fertilizers due to the activity of soil microbiota. Although bacteria and fungi harbor genes permitting denitrification, fungi lack NosZ, an enzyme responsible for reducing N2O into inert N2 gas. Historically, scientists have linked fungi …
Cellular/Molecular Analysis Of Interspecies Sterile Male Hybrids In Drosophila, Rachelle L. Kanippayoor
Cellular/Molecular Analysis Of Interspecies Sterile Male Hybrids In Drosophila, Rachelle L. Kanippayoor
Electronic Thesis and Dissertation Repository
Over time, genetic differences can accumulate between populations that are geographically separated. This genetic divergence can lead to the evolution of reproductive isolating mechanisms that reduce gene flow between the populations and, upon secondary contact, result in distinct species. The process of speciation is, thus, what accounts for the multitude of species that contribute to the rich biodiversity on Earth. Interspecies hybrid sterility is a postzygotic isolating mechanism that affects the development of hybrids, rendering them sterile. A notable trend, known as Haldane's Rule, describes that heterogametic individual (e.g. males in Drosophila) are more susceptible to sterility than homogametic …
Lichen Conservation In Eastern North America: Population Genomics, Climate Change, And Translocations, Jessica Allen
Lichen Conservation In Eastern North America: Population Genomics, Climate Change, And Translocations, Jessica Allen
Dissertations, Theses, and Capstone Projects
Conservation biology is a scientific discipline that draws on methods from diverse fields to address specific conservation concerns and inform conservation actions. This field is overwhelmingly focused on charismatic animals and vascular plants, often ignoring other diverse and ecologically important groups. This trend is slowly changing in some ways; for example, increasing number of fungal species are being added to the IUCN Red-List. However, a strong taxonomic bias still exists. Here I contribute four research chapters to further the conservation of lichens, one group of frequently overlooked organisms. I address specific conservation concerns in eastern North America using modern methods. …
The Population Genetics Of Morro Bay Eelgrass (Zostera Marina), Julia Gardner Harencar
The Population Genetics Of Morro Bay Eelgrass (Zostera Marina), Julia Gardner Harencar
Master's Theses
Seagrass populations are in decline worldwide. Zostera marina (eelgrass), one of California’s native seagrasses, is no exception to this trend. In the last 8 years, Morro Bay, California has lost 95% of its eelgrass. Eelgrass is an ecosystem engineer, providing important ecosystem services such as sediment stabilization, nutrient cycling, and nursery habitats for fish. The failure of recent restoration efforts necessitates a better understanding of the causes of eelgrass decline in this estuary. Previous research on eelgrass in California has demonstrated a link between population genetic diversity and eelgrass bed health, ecosystem functioning, and resilience to disturbance and extreme climatic …
Evolutionary Genetic Aspects Of Host Association In Generalist Ectoparasites, Benoit Talbot
Evolutionary Genetic Aspects Of Host Association In Generalist Ectoparasites, Benoit Talbot
Electronic Thesis and Dissertation Repository
Despite the use of the host for dispersal by most parasite species, the extremely loose relationship typical between highly mobile hosts and generalist ectoparasites may lead to very different gene flow patterns between the two, leading in turn to different spatial genetic structure, and potentially different demographic history. I examined how similar gene flow patterns are between Cimex adjunctus, a generalist ectoparasite of bats present throughout North America, and two of its key bat hosts. I first analyzed the continent-scale genetic structure and demographic history of C. adjunctus and compared it to that of two of its hosts, the …
Systematics, Diversification, And Functional Diversity Of Russulaceae (Russulales), Brian Patrick Looney
Systematics, Diversification, And Functional Diversity Of Russulaceae (Russulales), Brian Patrick Looney
Doctoral Dissertations
The family Russulaceae is an iconic family of mushroom-forming Basidiomycetes both because of their importance as edible mushrooms in many parts of the world and their species richness in both temperate and tropical forested biomes. While much mycological research has been focused on this group, recent systematic and ecological research has failed to develop a comprehensive or cohesive organization by which to understand the evolutionary relationships, patterns of diversification, or functional importance of the group. Recently, interest in ectomycorrhizal fungi (EmF), of which Russulaceae is a key lineage, has greatly increased due to the recognition of the importance of EmF …
Using Phylogenetic Comparative Methods To Understand Diversification And Geographic Range Evolution, Kathryn Aurora Massana
Using Phylogenetic Comparative Methods To Understand Diversification And Geographic Range Evolution, Kathryn Aurora Massana
Doctoral Dissertations
Two key processes that have been modeled in a phylogenetic comparative framework are diversification and historical biogeography. Many questions arise on what process have shaped the abundance (or lack) of species we see today and what influences their survival and interconnectedness with other species. Many methods have been developed to answer these questions. Over the past several decades there has been a rise in parametric modeling and development of more adequate frameworks to answer biological questions of interest. However, many models still lack the incorporation of ecological, mainly biotic factors, which influence the evolution and ecology of species, while accounting …
Microbial Repopulation Following In Situ Star Remediation, Gavin Overbeeke
Microbial Repopulation Following In Situ Star Remediation, Gavin Overbeeke
Electronic Thesis and Dissertation Repository
In situ STAR (Self-sustaining Treatment for Active Remediation) is an emerging remediation technology which uses smouldering combustion to destroy nonaqueous phase liquid (NAPL) contamination in the subsurface. Since STAR smouldering travels through contaminated soils slowly (~0.5 to 5 m/day) and subjects them to high temperatures (400–1000°C), it is expected that this technology will thoroughly dry and sterilize the zones which it treats. Further, soils surrounding the treatment zone which are not smouldered will be heated, although not smouldered, by virtue of their proximity to STAR, impacting microbial communities within them. Therefore, the objectives of this work are to quantify the …
Antifungal Genome Mining And Genetics In Filamentous Actinomycete Bacteria Isolated From Local Soils, Jacob Alex, Kevin Lou, Bilal Makhdoom
Antifungal Genome Mining And Genetics In Filamentous Actinomycete Bacteria Isolated From Local Soils, Jacob Alex, Kevin Lou, Bilal Makhdoom
Undergraduate Research Symposium Posters
Actinomycetes are gram positive, filamentous bacteria that produce useful antibiotics, antitumor agents, and agricultural products. A series of enrichments were undertaken to isolate actinomycetes from local soils, varying enrichment media, antibacterials, and soil treatments (including heat and CaCO3). Isolates were characterized by 16S rDNA sequencing, phenotypic and morphological observations, and antibiotic production. The genetic tractability of select isolates was analyzed using a panel of integrating vectors derived from ɸC31, ɸBT1, and OzzyJ phage using intergeneric conjugation. Further, a semi-degenerate multiplex PCR assay to detect ɸBT1 genomic integrants was designed and tested for the first time. Finally, PCR screens were used …
Genomic Perspectives On Amphibian Evolution Across Multiple Phylogenetic Scales, Paul Michael Hime
Genomic Perspectives On Amphibian Evolution Across Multiple Phylogenetic Scales, Paul Michael Hime
Theses and Dissertations--Biology
Genomes provide windows into the evolutionary histories of species. The recent accessibility of genome-scale data in non-model organisms and the proliferation of powerful statistical models are now providing unprecedented opportunities to uncover evolutionary relationships and to test hypotheses about the processes that generate and maintain biodiversity. This dissertation work reveals shallow-scale species boundaries and population genetic structure in two imperiled groups of salamanders and demonstrates that the number and information content of genomic regions used in species delimitation exert strong effects on the resulting inferences. Genome scans are employed to test hypotheses about the mechanisms of genetic sex determination in …
Determining The Reproductive Patterns Of The Titan Acorn Barnacle (Megabalanus Coccopoma) In Its Introduced Range, Isabel L. Moran Ms.
Determining The Reproductive Patterns Of The Titan Acorn Barnacle (Megabalanus Coccopoma) In Its Introduced Range, Isabel L. Moran Ms.
Honors College Theses
Invasive species are a significant conservation concern given their contribution to native species decline. The barnacle, Megabalanus coccopoma, is a common invasive species in tropical and subtropical regions of both the Pacific and Atlantic oceans. Little is known about the life history and ecology of M. coccopoma, and data on reproductive biology could provide valuable insight into its propensity to establish introduced populations. Most species of barnacle (including M. coccopoma) are hermaphroditic, but self-fertilization is rare in species studied to date. A recent genetic study of introduced M. coccopoma populations in the southeastern US showed high levels of …
Neutral And Adaptive Genetic Variation In North American Hardwood Tree Species, Sudhir Khodwekar
Neutral And Adaptive Genetic Variation In North American Hardwood Tree Species, Sudhir Khodwekar
Dissertations, Master's Theses and Master's Reports
'Northern Hardwoods,’ are a characteristic composition of multiple tree species and a part of the rich and diverse northeastern forests. Hardwoods e.g. oaks (Quercus: Fagaceae and Sugar maple), serve as foundation species and offer ecological and economical gains to wildlife and humans. Most of the forest trees go through many biotic and abiotic stresses, for example climate change in their long life span. To overcome these threats and to adapt to changing conditions, tree species need to maintain variation especially in adaptive genes. Therefore, it is necessary to analyze genetic diversity within forest tree populations and take appropriate …
Analysis Of Microbial Diversity In Disturbed Soil, Tyler G. Sanda
Analysis Of Microbial Diversity In Disturbed Soil, Tyler G. Sanda
Williams Honors College, Honors Research Projects
This paper uses the composition and abundance of microbial species to analyze soil recovery in disturbed land. Surface mining disturbs ecological communities throughout the world. As organizations seek to reclaim these disturbed lands, a proper analysis of recovery is needed. In previous studies, recovery of disturbed land was limited to surface examinations, which do not characterize the possible unseen devastating effects of the subsoil. Soil microorganisms are extremely sensitive to environmental changes such as strip mining. It is proposed that these microorganisms may serve as better indicators of recovery post disturbance. Our analysis indicates microbial recovery, however it may not …
¬Multilocus Phylogeny Of The Lichen Family Megasporaceae, Tim B. Wheeler
¬Multilocus Phylogeny Of The Lichen Family Megasporaceae, Tim B. Wheeler
Graduate Student Theses, Dissertations, & Professional Papers
The lichen symbiosis is one of the oldest studied mutualisms; in fact, Frank and De Bary coined the term "symbiosis" while studying lichens (Frank, 1877; De Bary 1879). The widespread, stable association between the mycobiont and photobiont in lichens offers an ideal system for the study of co-evolution. The recent application of molecular data to lichens has begun to unveil the complexities involved in these associations (Upreti et al. 2015, Spribille et al. 2016). Lichenized fungi make up a huge fraction of fungal diversity (Nash 2008), yet very little is known of their genetic diversity. Fungal taxonomy is notoriously difficult …