Life Sciences Commons^™

Conservation And Variation Of Dna Methylation In Lactuca Sativa And Lactuca Serriola, Trudi A. Baker

Graduate Doctoral Dissertations

Molecular techniques for guiding plant breeding have successfully used wild progenitors of domestic crops as sources of genetic variants conveying desirable traits. However, epigenetic variation, in particular DNA methylation, is a significant source of phenotypic variation and epigenetic effects of plant domestication are poorly understood. Described herein are the first single-base pair resolution methylomes of the highly valued crop iceberg lettuce (Lactuca sativa cv. Salinas) and its close relative, and ubiquitous weed, L. serriola. This work suggests several roles for acquisition and inheritance of methylation in the evolution of Lactuca spp. in response to stress. The Lactuca spp. have conserved …

Morphological And Gene Expression Plasticity In Neotropical Cichlid Fishes, Sharon Fern Clemmensen

Doctoral Dissertations

Trophic divergence in cichlid fish is linked to morphological shifts in the pharyngeal jaw apparatus. For instance, in the Heroine cichlids of Central America, the ability to crush hard-shelled mollusks is a convergent phenotype with multiple evolutionary origins. These durophagous species often have very similar pharyngeal jaw morphologies associated with the pharyngeal jaw apparatus and some of these similarities could be due to phenotypically plastic responses to mechanical stress. I examined the durophagous cichlid Vieja maculicauda for differences in pharyngeal osteology, dentition, and soft tissues when exposed to different diet regimes. Here I discuss the effect on the morphology and …

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 …

Emerging Infectious Disease And The Imperiled Relict Leopard Frog, Anthony Wayne Waddle

UNLV Theses, Dissertations, Professional Papers, and Capstones

The disease chytridiomycosis, caused by the aquatic fungal pathogen Batrachochytrium dendrobatidis (Bd), has emerged as a major contributing factor for worldwide amphibian declines. Although relatively recently described, the impacts from the disease this pathogen causes have been definitively tied to amphibian declines, including some that occurred decades ago. In some cases, declines of individual species occurred with little documentation and are thus poorly understood. The relict leopard frog (Rana onca = Lithobates onca) has experienced such a decline and by the latter part of the 20th century only occurred in two general areas in southern Nevada. Recent research has found …

Acute Salivary Steroid Hormone Responses During Coalitional And Dyadic Competitions In Hong Kong Juvenile Children, Timothy Mchale

UNLV Theses, Dissertations, Professional Papers, and Capstones

A large body of research links testosterone and cortisol responses to competition during adulthood. Little psychoneuroendocrine research has explored salivary steroid hormone responses to competition during middle childhood. This project investigated the relationship between acute salivary steroid hormone change, performance, competitor type, and outcome effects in three different field studies, while controlling for Body Mass Index (BMI) and pubertal development, in a population of ethnically Chinese, Hong Kong juvenile children, 8-11 years of age. The relative dynamics of salivary steroid change were assessed during a 1) coalitional physical competition (soccer) in boys, 2) a non-physical mixed-sex coalitional competition (math contest), …

Morphological, Genetic, And Environmental Characterization Of An Unusual Population Of Isoetes (Isoetaceae, Lycopodiophyta), Shannon L. Walker

Honors Theses

A large and unusual population of Isoetes (Isoetaceae, Lycopodiophyta) in the DeSoto National Forest, Wayne County, Mississippi, was studied to determine if the individuals there represent a new species or if they represent part of the variation of the one primary species of the longleaf pine belt of Mississippi, Isoetes louisianensis, which it most closely resembles. The unusual population and specimens of known Isoetes louisianensis were examined comparatively based on morphology, megaspore ornamentation, examination of habitat characteristics, and phylogenetic analysis of DNA sequence data from the nuclear internal transcribed spacer 1 and 2 (ITS) and the 5.8S ribosomal gene. No …

All Roads Lead To Weediness: Stories About Weedy Rice Origins, Weedy Genes And Weed Competitiveness, Zhongyun Huang

Doctoral Dissertations

Weedy rice (Oryza spp.), a weedy relative of cultivated rice (O.sativa), infests and persists in cultivated rice fields worldwide. Many weedy rice populations have evolved similar adaptive traits, considered part of the ‘agricultural weed syndrome’, making this an ideal model to study the genetic basis of parallel evolution. Using population genetics analyses of South Asian and US weedy rice, my research reveals multiple independent evolution events giving rise to weed groups in the two geographic areas. Weeds in South Asia have highly heterogenous genetic backgrounds, with contributions from both cultivated varieties (aus and indica) …

Response To Nitrogen And Salinity Conditions In Rhizophora Mangle Seedlings Varies By Site Of Origin, Kristen L. Langanke

USF Tampa Graduate Theses and Dissertations

Many coastal plant species thrive across a range of environmental conditions, often displaying dramatic phenotypic variation in response to environmental variation. We characterized the response of the critical foundation species Rhizophora mangle L. to full factorial combinations of salt and nitrogen (N). We used seedlings collected from five populations and measured traits related to salt tolerance and N amendment. The response to increasing salt included significant plasticity in succulence, leaf mass area (LMA), and root to shoot ratio (R:S). Seedlings also showed overall reduced maximum photosynthetic rate in response to N amendment, but this response depended on the level of …

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 …

Comparative Phylogeographic, Population Genomic, And Selection Inference With Development Of Hierarchical Co-Demographic Models, Alexander Xue

Dissertations, Theses, and Capstone Projects

Comparing demographic histories across assemblages of populations, species, and sister pairs has been a focus in phylogeography since its inception. Initial approaches utilized organelle genetic data and involved qualitative comparisons of genetic patterns for evaluating hypotheses of shared evolutionary responses to past environmental changes. This endeavor has progressed with coalescent model-based statistical techniques and advances in next-generation sequencing, yet there remains a need for methods that can analyze aggregated genomic-scale data from non-model organisms within a unified framework that considers individual taxon uncertainty and variance. To this end, the aggregate site frequency spectrum (aSFS), an expansion of the site frequency …

Climate-Driven Habitat Shifts In South America: Biogeography, Historical Demography, And Population Genomics Of Anole Lizards, Ivan Prates

Dissertations, Theses, and Capstone Projects

Shifts in the geographic distribution of habitats over time can promote dispersal and vicariance, thereby influencing large-scale biogeographic patterns and ecological processes. The establishment of corridors of suitable habitat across previously disjunct yet ecologically similar regions has been widely linked to climate change over time. Such climate-mediated habitat changes may have played a key role in the assembly of tropical biotas, including those of Amazonia and the coastal Atlantic Forest in South America, two of the most diverse ecosystems on Earth. The history of biogeographic associations between tropical rainforest habitats in response to former climatic shifts, as well as their …

The Solid & The Shifting: Darwinian Time, Evolutionary Form And The Greek Ideal 
In The Early Works Of Virginia Woolf, Joseph Monroe Kreutziger

Arts & Sciences Electronic Theses and Dissertations

ABSTRACT OF THE DISSERTATION

“The Solid & the Shifting”: Evolutionary Form, Darwinian Time, and the Greek Ideal in the Early Works of Virginia Woolf

By

Joseph Kreutziger

Doctor of Philosophy in English and American Literature

Washington University in St. Louis, 2017

Professors Melanie Micir, Robert Milder, Steven Meyer, Vincent Sherry, Zoe Stamatopoulou

_____________________________________________________________________

“Now is life very solid or very shifting?” Virginia Woolf asks in her diary of 1931, a question she claims haunts her in its contradictions. This dynamism between the solid and the shifting aspects of life and temporality is fundamental to an analysis of Woolf’s writing process. …

The Influence Of Phylogeny And Niche Differentiation On The Diets Of Malagasy Primates, Rebekka S. Hughes

Theses and Dissertations

Previous studies have shown that haplorhine diet is affected by phylogeny; however, until now studies in Malagasy strepsirrhines were lacking. The evolution of differences in Malagasy primates’ diets appears to differ from the pattern shown in haplorhines. My results indicate that niche differentiation may be a stronger predictor of diet.

Unravelling Organelle Genome Transcription Using Publicly Available Rna-Sequencing Data, Matheus Sanita Lima

Electronic Thesis and Dissertation Repository

The study of organelles helped forge theories of genome evolution because of their unconventional genomes and gene expression regimes. The organelle genomics field (~35 years old) has seen the development of next generation sequencing (NGS) techniques and the consequent skyrocketing of genomic and transcriptomic data. However, these data are being underused in the studies of organelle genome transcription. My thesis investigates how NGS has affected the field of organelle genomics at both the DNA and RNA levels. First, I demonstrate that although organelle genomes are being sequenced as never before, they are un-characterized as they are published mostly as “organelle …

The Interommatidial Bristle Variability Of Diptera, Kimberly Palmer

Honors College Theses

Insects of the order Diptera are a popular biological model for understanding morphological trait evolution. One area of particular interest is the development of the compound eyes. While the development of ommatidia and photoreceptors has been thoroughly studied in this case, little attention has been paid to the interommatidial bristles (IOBs) present on the eyes of some dipteran families. A preliminary survey suggested that these bristles exhibit high variability among IOB families on multiple taxonomic levels and are not uniformly present or absent in any suborder of the Diptera. To confirm this observation, I conducted a literature search to …

Ecological Niche Modeling Of The Genus Papio, Amanda J. Fuchs

Theses and Dissertations

Ecological niche modeling investigates how climatic variables have influenced taxonomic diversity in Papio. Models performed well suggesting climatic variables influence the distribution of baboon species. Niche overlap among all possible pairs of taxa determined that species exhibited significantly different niches. The results of these models support a parapatric speciation scenario.

Stable Isotopes, Phylogenetics, And Experimental Data Indicate A Unique Nutritional Mode For Rickenella Fibula, A Bryophyte-Associate In The Hymenochaetales, Hailee Brynn Korotkin

Masters Theses

Fungal-bryophyte interactions have been documented in all lineages of bryophytes, however, many of these relationships are poorly understood. The fungus Rickenella fibula is a known associate of various mosses, but results from previous studies have not yielded conclusive evidence of its relationship to mosses or its trophic mode. The Rickenella clade exhibits a wide variety of nutritional modes, including other bryophyte-associated fungi. Here, I combine a broad range of methods, using phylogenetics, stable isotope analyses, PCR assays, in vitro experiments, and genomics to determine the nutritional mode of R. fibula. First, phylogenetic analysis of a supermatrix of 28S rRNA, …

Fleas Of The American Pika: Diversity And Biogeography In North America’S Intermountain West, Niyomi Wijewardena

All NMU Master's Theses

American pikas (Ochotona princeps) are small mammals that are widely distributed across North America’s Intermountain West. Previous investigations revealed five geographically distinct mitochondrial lineages within O. princeps associated with different mountain systems of the Intermountain West. In contrast, diversity of endoparasitic helminths of pikas is not structured geographically in the same way. Instead, there are two primary parasite assemblages, one distributed across southwestern pika populations and one found across the northeastern part of the host range. These contrasting patterns suggest that the shared history of pikas and their parasites had different consequences for the evolutionary trajectories of these …

The Role Of Phenotypic Integration In Mammalian Tooth Function And Jaw Morphological Diversity, Andrew Conith

Doctoral Dissertations

Here I investigate how two major components of the mammalian feeding system, teeth and jaws, are influenced by functional, environment, and developmental factors. First, I build physical models of the molars from two early mammals, Morganucodon and Kuehneotherium, and compare their ability to process a proxy food item. Early mammals were under strong selection to reduce metabolic costs, so any savings in energy during feeding would be advantageous. I tested the ability of both mammals to process a hard and soft food item with material properties similar to that of the insects they would have likely consumed. Morganucodon was …

Burrowing And Walking Mechanisms Of North American Moles, Yi-Fen Lin

Doctoral Dissertations

Moles (Family Talpidae) are a classic example of extreme specialization, in their case highly derived forelimb morphologies associated with burrowing. Despite many observations of mole burrows and behaviors gathered in the field, we know very little about how and how well moles use their forelimbs to dig tunnels and to walk within the built tunnels to collect and transport food. The first chapter investigates the effect of soil compactness on two sympatric mole species under controlled laboratory conditions. My results demonstrate that increasing soil compactness impedes tunneling performance as evidenced by reduced burrowing speed, increased soil transport, shorter tunnels, shorter …

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 …

Ecology, Evolution, And Sexual Selection In The Invasive, Globally Distributed Small Indian Mongoose (Urva Auropunctata), M. Aaron Owen

Dissertations, Theses, and Capstone Projects

Introduced species provide rare opportunities to test evolutionary hypotheses in situ by creating so-called natural experiments. Natural experiments are situations in nature that resemble laboratory studies by allowing for comparisons of a “control” group (i.e., a species’ native range) with “experimental” groups (i.e., a species’ introduced range). In particular, introduced animals allow us to investigate evolutionary dynamics in complex, long-lived organisms in ways that would otherwise be impossible in a laboratory setting. One such introduced animal is the small Indian mongoose (Urva auropunctata, formerly Herpestes auropunctatus). Native to South Asia, the small Indian mongoose’s introduction to more …

The Santa Ana Speckled Dace (Rhinichthys Osculus): Phylogeography And Molecular Evolution Of The Mitochondrial Dna Control Region, James Jay Vanmeter

Electronic Theses, Projects, and Dissertations

The purpose of this genetic study of the Santa Ana Speckled Dace Rhinichthys osculus was three-fold. The first goal was to characterize the molecular structure of the mtDNA control region of R. osculus. An 1143 base-pair region of the mitochondrial DNA genome, which included the complete control region was sequenced for all individuals. Analysis of the sequence data revealed that the molecular structure of the speckled dace control region was similar to the molecular structure described for other vertebrate taxa. The speckled dace control region contains three major domains, which vary in base frequency as well as in the frequency …

Evolvability: What Is It And How Do We Get It?, Matthew Moreno

Honors Program Theses

Biological organisms exhibit spectacular adaptation to their environments. However, another marvel of biology lurks behind the adaptive traits that organisms exhibit over the course of their lifespans: it is hypothesized that biological organisms also exhibit adaptation to the evolutionary process itself. That is, biological organisms are thought to possess traits that facilitate evolution. The term evolvability was coined to describe this type of adaptation. The question of evolvability has special practical relevance to computer science researchers engaged in longstanding efforts to harness evolution as an algorithm for automated design. It is hoped that a more nuanced understanding of biological evolution …

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 …

Immunology Of The Gray Short-Tailed Opossum During Pregnancy And Prenatal Development, Victoria L. Hansen

Biology ETDs

Vertebrate species that bear live young have overcome the evolutionary challenge of maintaining both a functional adaptive immune system and viviparous life cycle. In normal pregnancy, viviparous mothers are able sustain and nourish a fetus that is genetically half non-self without mounting an immunological attack. In 1953 Sir Peter Medawar brought attention to the “enigma of the fetal graft” and immunologists have been puzzling out the intricacies of fetal tolerance ever since. Although viviparity has evolved in all jawed vertebrate lineages aside from Aves, the vast majority of reproductive immunology research has been limited to eutherian mammals. There are insights …

The Biogeographic Origins And Trophic Ecology Of Maine’S Island Red-Backed Salamanders (Plethodon Cinereus), Nikko-Ideen Shaidani

Electronic Theses and Dissertations

Island populations of terrestrial species have an increased potential, compared to mainland populations, to adapt and diverge, as these populations often are isolated with respect to gene flow from other populations and may be subjected to novel pressures. Indeed, extended isolation of individuals can elicit dramatic changes within populations and is recognized as a common driver of speciation. It is for these reasons that island populations are often a priority for conservation. Plethodontid salamanders are among the most terrestrial of Maine’s amphibians and are not tolerant of prolonged exposure to seawater, and yet, they are found on a number of …

Genetics Of Female Interspecific Mate Rejection In Species Of Drosophila, Ryan Calhoun

Electronic Thesis and Dissertation Repository

Speciation can occur when accumulated differences in mating behavior force diverging species to remain reproductively isolated from one another. A key determinant of behavioural isolation is the evolution of female mating preferences that prevent interspecific males from mating. However, no individual genes involved in species-specific preferences of females have yet been identified. Using various genetic mapping techniques available for studying strains and species of Drosophila, I identify candidate genes involved in D. simulans female discrimination against D. melanogaster males. One candidate gene in particular, Katanin-60, was selected for further characterization. Katanin-60 is a gene encoding a microtubule severing …

African Wild Dog, Lycaon Pictus, Coloration Patterns And Social Aggregation, Ayong J. Kim

Theses and Dissertations

Packs of African wild dogs, Lycaon pictus, were analyzed for coloration patterns and social aggregation tendencies. Mapped locations determined if the coat patterns followed a geographic distribution that corresponded to Southern or Eastern phenotypic forms. Social aggregation tendencies were observed to determine grouping behavior presumably related to individuals’ roles.

Scaling Of Anatomically Derived Maximal Bite Force In Primates, Ashley Deutsch

Senior Theses

Bite force analysis is important the examination of the evolutionary factors that have shaped the masticatory apparatus. Unfortunately, in primates, empirically measured bite force is largely unavailable because of the invasive nature of the procedure. Because of this, we have estimated bite force in a large sample across the primate order at three different realistic bite points along the tooth row: the first maxillary incisor, the maxillary canine, and the paracone of the first maxillary molar. Here, we model bite force by combining measured physiological crosssectional area of the jaw adductors from Hartstone-Rose and colleagues (2017) with osteological measurements from …