Cell and Developmental Biology Commons^™

Species Delimitation Of Slimy Salamanders, Plethodon Kisatchie And Plethodon Mississippi, Across The Lower Mississippi River, Brock Hunter Stevenson

Master's Theses

Species are fundamental units of biodiversity yet delimiting species can be challenging. Slimy Salamanders of the Plethodon glutinosus species complex are a classic example of cryptic species for which species boundaries and relationships have proved difficult to determine. Once thought to be a single species ranging across the eastern United States, protein analysis revealed high genetic divergences among geographically distinct groups of populations, leading to 16 species being recognized within the group. Two of these species, the Louisiana Slimy Salamander (Plethodon kisatchie) and the Mississippi Slimy Salamander (Plethodon mississippi), are closely related but occur on opposite sides of the Mississippi …

Breaking Virulent: The Coincidental Evolution Of Virulence Factors In Bacteria., Rhiannon Emmanuelle Cecil

Electronic Theses and Dissertations

Understanding how innocuous organisms can evolve to be pathogenic to humans is of increasing global concern. Further, understanding how existing pathogens may evolved to be more virulent is also vital to our ability to provide healthcare to people afflicted with diseases that promote chronic bacterial infections, such as cystic fibrosis. With the rise of antibiotic resistance in both bacteria and fungi it is paramount that new therapeutics are identified. Understanding what mutations occur that result in increased virulence in microbes can potentially provide new targets for antimicrobial drugs to combat antibiotic resistance. The Coincidental Evolution Hypothesis is a fundamental hypothesis …

Evaluation Of Nutrient Digestibility Of Weaned Calves From Early And Late Shedding Dams, Jennifer Keele

Theses and Dissertations

Researchers have investigated several factors that could alter fetal growth, including nutrient restriction (Valiente et al., 2021), hair shedding (Gray et al., 2011), and extreme hot and cold temperatures (Davidson et al., 2022). Hot temperatures and increased humidity percentages in the southeast United States caused researchers to investigate the hair coats of Angus cattle in the commercial production setting. An improvement in fiber digestibility and calf birth and weaning weights has been observed in Angus dams that shed 50% of the winter hair coat by May (Gray et al., 2011; Burnett et al., 2021). Our objective of this experiment was …

Rattus Norvegicus As A Biological Detector Of Clandestine Remains And The Use Of Ultrasonic Vocalizations As A Locating Mechanism, Gabrielle M. Johnston

Master's Theses

In investigations, locating missing persons and clandestine remains are imperative. One way that first responder and police agencies can search for the remains is by using cadaver dogs as biological detectors. Cadaver dogs are typically used due to their olfactory sensitivity and ability to detect low concentrations of volatile organic compounds produced by biological remains. Cadaver dogs are typically chosen for their stamina, agility, and olfactory sensitivity. However, what is not taken into account often is the size of the animal and the expense of maintaining and training the animal. Cadaver dogs are typically large breeds that cannot fit in …

Trace Dna Detection Using Diamond Dye: A Recovery Technique To Yield More Dna, Leah Davis

Master's Theses

This study aspires to find a new screening approach to trace DNA recovery techniques to yield a higher quantity of trace DNA from larger items of evidence. It takes the path of visualizing trace DNA on items of evidence with potential DNA so analysts can swab a more localized area rather than attempting to recover trace DNA through the general swabbing technique currently used for trace DNA recovery. The first and second parts consisted of observing trace DNA interaction with Diamond Dye on porous and non-porous surfaces.

The third part involved applying the Diamond Dye solution by spraying it onto …

Analysis Of Wild Rodent Gut Microbiota As A Function Of Exposure To Ticks And Tick-Borne Pathogens, Joshua Pandian

Honors Theses

Due to advances in high-throughput parallel sequencing, researchers have conducted novel studies exploring relationships between microbiome compositions and different aspects of organism health. Some of these studies have shown that the gut microbiome of rodent models has effects on organism health and behavior and that infection with pathogens and the composition of the skin microbiome are linked to changes in gut microbiome composition. While previous studies have shown how vector microbiota impact vector behavior and pathogen transmission, the effect vectors have on reservoir species microbiomes has been a less prominent focus. We were interested in the relationships between tick parasitism, …

A Cladoxylopsid With Complex Vascular Architecture From The Early Devonian Battery Point Formation (Québec, Canada), Jessica Chu

Cal Poly Humboldt theses and projects

Cladoxylopsids are seed-free plants that formed the world’s earliest forests and gave rise to horsetails (sphenopsids), but their evolutionary origins are poorly understood. Here, I describe a new Early Devonian cladoxylopsid from the Emsian (400-395 Ma) Battery Point Formation (Québec, Canada). The structural features of this plant indicate taxonomic affinity to cladoxylalean cladoxylopsids and its phylogenetic position supports placement in genus Cladoxylon (the proposed name, Cladoxylon kespekianum sp. nov., to be formalized by peer-reviewed publication). Specimens of this plant are permineralized in calcium carbonate and were studied using the acetate peel technique with light and electron microscopy. Cladoxylon kespekianum is …

Genetic Evaluation Of The Current Distribution And Possible Diffrentations Between Lasiurus Borealis And Lasiurus Frantzii In Southwestern North America, Zeinab M. Haidar

Cal Poly Humboldt theses and projects

Several recent accounts of overlap and historic misidentifications regarding two species of the genus Lasiurus, Western red bat (Lasiurus frantzii) and Eastern red bat (Lasiurus borealis), have cast doubt on our understanding of their distribution, assumed spatial allopatry, and interactions in the United States Southwest. With the use of morphometrics and genetic sequencing, utilizing tissue collected from specimens throughout California and adjoining states, we have reassessed the current distribution, best practices for field identification, and genetic differentiation between both species. Appropriate species classification by region was achieved utilizing mitochondrial DNA, targeting the cytochrome c oxidase …

The Links To Cancer: How Golf Became Dangerous And What We Can Do To Save The Game, Meredith Boos

Undergraduate Theses, Professional Papers, and Capstone Artifacts

This study is a comprehensive meta-analysis on health claims linked to exposure to golf courses, more specifically the chemicals used to maintain their appearance. It provides a brief history of the golf industry and how its growth exacerbated the environmental impact as well as an explanation of the legal landscape that will affect golf course management. Golf courses can disrupt local ecologies, contaminate ground water, rivers, lakes and streams with run-off, and be responsible for the bioaccumulation of chemicals which remain dangerous for decades. Despite the adverse effects of golf courses on the environment, there remains an opportunity to transform …

Cooperation And Conflict In The Social Amoeba Dictyostelium Discoideum And Its Paraburkholderia Endosymbionts, James Medina

Arts & Sciences Electronic Theses and Dissertations

A big question in biology is how organisms compete in an environment of competitors for scarce resources. Part of the answer lies in distinguishing friend from foe and in forging cooperative bonds in the face of cheaters. The social amoeba – bacteria system I have studied here is an excellent place to explore these tensions. The first part of my thesis research involves a review of cooperation and conflict in the social amoeba Dictyostelium discoideum and a study of the limits on obligate social cheating in this species. The second part focuses on the benefits of associating with D. discoideum …

Inferring Adaptation In Social Microbes From Experimental Evolution Under Relaxed Selection, Tyler John Larsen

Arts & Sciences Electronic Theses and Dissertations

Microbes exist against a backdrop of other organisms, and the interactions between microbes have major consequences on their traits, their evolution, and their impact on the world. Microbial interactions and the adaptations that enable them are extremely diverse – they can unlock abilities beyond the reach of individual cells or lead to a population’s destruction, they can be temporary or permanent, they can be between genetically identical cells or different species entirely. The first chapter of this dissertation reviews microbial interactions and the related concept of the evolution of conflict and cooperation.To be certain a trait is an adaptation at …

Roles Of Behavioral Novelty And Organismal Energetics In The Evolution Of Extreme Encephalization, Erika Laurie Schumacher

Arts & Sciences Electronic Theses and Dissertations

Brains and their component brain regions vary widely in size and structure across vertebrates. However, extreme increases in total brain size relative to body size (extreme encephalization) and increases in specific major brain region sizes independent of other brain regions (mosaic brain evolution) are relatively rare. There are several hypotheses as to why, but the energetic cost of increased brain tissue and the regional interconnectedness in both brain development and function likely constrain how brains are able to change in response to selection. In this dissertation, I sought to address both how behavioral novelty relates to evolutionary changes in brain …

Light And Temperature Entrainment Of Two Circadian-Driven Behaviors In The Flesh Fly Sarcophaga Crassipalpis, Raven Ragsdale

Electronic Theses and Dissertations

Circadian rhythms dictate the timing of both once-in-a-lifetime adult emergence (eclosion) and daily locomotor activity rhythms in the flesh fly S. crassipalpis. Light cycles are considered the primary environmental time cue (zeitgeber), but the life history of S. crassipalpis suggests that temperature cycles (thermocycles) may also play a key role. This work evaluates the efficacy of thermocycling as a zeitgeber in S. crassipalpis. We found that shifting both light and temperature cycles of sufficient amplitude affect the phasing of eclosion and locomotor activity, but result in different patterns. Additional experiments suggest greater thermocycle sensitivity during the late metamorphic …

Investigating The Potential Role For The Nervous System In Controlling Regeneration In Nematostella Vectensis, Kristen Malir

Biological Sciences Undergraduate Honors Theses

Nematostella vectensis is a marine sea animal that has become a model for developmental and evolutionary research. Included in the phylum Cnidaria, N. vectensis’ was chosen as the model for this research. Not only can this animal go through asexual and sexual reproduction, but it also has the ability to regenerate. Although much research has been put forth in an effort to understand regeneration better, much is still unknown. The underlying mechanisms of regeneration in Cnidaria are illusive; however, studies within vertebrates have shown the substantial role of the nervous system. The objective of this experiment is to test if …

Connexin 43 Contributes To Phenotypic Variability Of The Mouse Skull, Elizabeth Jewlal

Electronic Thesis and Dissertation Repository

The purpose of this study was to determine whether connexin 43 (Cx43) contributes to craniofacial phenotypic variability. Skull shape and variation were compared within and among two heterozygous mutant mouse models (G60S/+ and I130T/+) that exhibit different levels of Cx43 channel function when compared to their wildtype counterparts (~80% and ~50% reduction in function, respectively). Results indicated mutants have significant differences in skull shape compared to wildtype littermates. Similar patterns of shape difference were found in both mutants. Increased skull shape variation and a disruption in the covariation of skull structures were observed in G60S/+ mutants only. These results show …

Modeling Jadera Haematoloma’S Phenotypic Variation In The Context Of Its Developmental Plasticity, Michael C. Yorsz

Honors Theses

Phenotypic plasticity is the ability of an organism to integrate information from environmental cues to inform the development of its phenotype and remains understudied in biology. Models of plasticity are needed because evolution in the presence of plasticity is poorly understood. Jadera haematoloma, a hemimetabolous true bug, is an excellent animal model of plasticity, exhibiting a non-linear plastic response to juvenile nutrition that biases adult development into groups with differences in flight capability, wing shape, and fecundity. However, there is a lack of literature consensus regarding the range of developmental outcomes in the species. Some publications report the presence …

Nutrient Scarcity And Cellular Cooperation In A Clonal Hydroid, Weam S. El Rahmany

Graduate Research Theses & Dissertations

Biological complexity forms when lower-level units (e.g., genes, cells, organisms) cooperatively band together. This complexity may be exemplified by multicellularity, the cooperation between the cells of the same species, or symbiosis, cooperation between the cells of different species. This cooperation is under continual threat, as defection, the opposite of cooperation, is favored by default by lower-level units (i.e., cells). Animal cancers may be the most well-known phenomena that exemplify the concept of cellular defection. Cancer cells have been shown to feature morphological and metabolic traits, developed through differential gene expression or mutations, that favor their growth at the cost of …

Identifying The Human Homologs Of Yeast Rab Proteins Ypt10 & Ypt11 And A Global-Scale Louse Endosymbiont Genome Variation, Nathaniel P. Smith

Theses and Dissertations

Amyotrophic lateral sclerosis (ALS) is a late-onset fatal neurodegenerative disease that causes loss of upper and/or lower motor neurons, and currently has no treatment or cure available. Over 90% of cases occur spontaneously with unknown causes, highlighting the complexity of the disease, and only 10% of cases are linked to heritable genetic mutations. Numerous ALS-linked genes are conserved through evolution, and model organisms may therefore provide opportunities to understand disease pathology at a molecular or cellular level, proving instrumental in identifying therapeutic targets. ALS subtype 8 (ALS8) is caused by an autosomal dominant P56S mutation in the VAPB gene that …

Getting To The Root Cause: The Genetic Underpinnings Of Root System Architecture And Rhizodeposition In Sorghum, Farren Smith

Graduate Theses, Dissertations, and Problem Reports

Plants are some of the most diverse organisms on earth, consisting of more than 350,000 different species. To understand the underlying processes that contributed to plant diversification, it is fundamental to identify the genetic and genomic components that facilitated various adaptations over evolutionary history. Most studies to date have focused on the underlying controls of above-ground traits such as grain and vegetation; however, little is known about the “hidden half” of plants. Root systems comprise half of the total plant structure and provide vital functions such as anchorage, resource acquisition, and storage of energy reserves. The execution of these key …

Comprehensive Study Of Human Pathogenic Trypanosomatids: From Chemotherapies To Disease Ecology, Felipe Rodriguez

Open Access Theses & Dissertations

The vector-borne diseases Leishmaniasis and Chagas disease, caused by the kinetoplastid parasites Leishmania spp. and Trypanosoma cruzi respectively, are among the most important parasitic diseases in the group of neglected tropical diseases. Even though the two diseases are endemic to the Americas, they affect millions of people worldwide. Leishmaniasis and Chagas disease cause a great array of symptoms and some of them can be fatal if left undiagnosed and untreated. Current treatment regimens are becoming less effective, vaccines are still not available, and diagnosis needs to be improved. Vector control has been responsible for a decrease of diseases in endemic …

Co-Option Of The Yolkless Oocyte Receptor For Crispr/Cas9 May Induce Transient Sterility In Female Drosophila Grimshawi Flies, Bronwyn Miller

University of New Orleans Theses and Dissertations

Evolutionary developmental biology has historically used generalist model organisms like Drosophila melanogaster. The Hawaiian Drosophilidae radiation, which occurred just 25 million years ago, is an ideal lineage for work in Evo-Devo. Hawaiian flies make up 25% of the world’s Drosophila species and extreme diversity is seen throughout the group. D. grimshawi is a generalist Hawaiian picture-wing fly that has served as a model for the Hawaiian Drosophilidae radiation. However, D. grimshawi’s power and use as a model organism is constrained by our lack of ability to manipulate its genome. In this work, I attempted to edit the genome of …

Testing Janzen’S Physiological Barrier Hypothesis Through Experimental Evolution And Biogeographic Studies On Sister Species Pairs, Vincent John Fasanello

Arts & Sciences Electronic Theses and Dissertations

Background: Janzen’s physiological barrier hypothesis suggests that variation in the effectiveness of physiological barriers to dispersal underlies global patterns of speciation and biodiversity. He noted that because a species’ physiology often evolves to match the range of conditions it has experienced in evolutionary history, it is likely that lineages that occupy habitats with wider ranges of temperature variation will tend to be better at dispersing across thermal gradients and will therefore be less likely to speciate as a result of mountain barriers. Despite decades of research into different aspects of this fundamental hypothesis, its assumptions and predictions remain largely untested. …

The Impacts Of Embryonic Arsenic Exposure Of Fundulus Heteroclitus, Torey Bowser

Electronic Theses and Dissertations

Arsenic is a toxic metalloid that exceeds safe drinking water standards in groundwater in many locations worldwide. Arsenic exposure in fish has been linked to destruction of gill tissues, impairment of growth, decreased muscle mass, memory impairment, increased aggression, and avoidance behaviors. We examined the behavior of mummichogs (Fundulus heteroclitus) following arsenic exposure during development in two studies. Embryos were collected from fish from three reference sites: Scorton Creek (SC), Massachusetts, Wells Harbor (WE), Maine, and Block Island (BLOC), Rhode Island and two contaminated sites: Callahan Mine (CM), Brooksville, Maine, and New Bedford Harbor (NBH), Massachusetts. Embryos were …

Host-Parasite Interactions Within Food Webs, Adam Zvanut Hasik

Graduate Theses and Dissertations

Parasitism is one of the most common life history strategies employed in nature, yet the effects of parasites are often thought to be minimal, and the vast majority of studies fail to consider parasites and their effects on host organisms. This is likely a problem, as the magnitude of parasite-mediated effects on their hosts can be quite large. Additionally, the effects of parasites are known to extend beyond the host to affect other species interactions. I used a series of approaches to gain a more integral understanding of host-parasite interactions by studying (1) the effects of parasites on biotic interactions …

Analysis Of Differential Gene Expression Patterns During Spiral Intestine Development In Leucoraja Erinacea, Kelsey Cox

Honors Theses

The vertebrate gut is a specialized structure responsible for the intake and digestion of food, absorption of nutrients, and expulsion of waste products. The organs of the digestive tract have been conserved over time, but modifications to the size and shape of individual structures exist within the different vertebrate lineages. The skate’s spiral intestine has evolved to maximize nutrient absorption within a compact structure to create space in the body cavity for the organs needed for buoyancy. Studying the unique intestinal morphology of Leucoraja erinacea, or the little skate, provides an opportunity to understand the role of differential gene expression …

The Phylogeography Of Rare Central Tennessee Glade Endemics Trifolium Calcaricum And Viola Egglestonii, Rachel Ann Lyman

Arts & Sciences Electronic Theses and Dissertations

Endemic species are range-restricted to a particular type of habitat and generally occur in a few small populations. Often endemic species are threatened or endangered due to their geographic isolation and limited habitat breadth. Despite the fact that understanding factors that may have shaped the evolutionary history of a species with a narrow distribution can provide important insights for their management and conservation, little is known about the historical forces that gave rise to many endemic species. Endemic species can arise because of factors such as variation in climate, geographic barriers, and habitat specificity, or the combination of several of …

The Genetic Basis Of Adaptation To Environmental Stress In Two Grass Genomic Model Systems, David Mitchell Goad

Arts & Sciences Electronic Theses and Dissertations

Plants are exposed to a wide variety of environmental stress in the wild and have developed an equally diverse set of adaptations to tolerate them. The evolutionary processes that have led to this functional diversification, and the specific genes and physiological mechanisms involved, are of immense interest to both evolutionary biologists and crop breeders. In this dissertation I investigate adaptation to different types of environmental stress in two economically important grass species, seashore paspalum (Paspalum vaginatum Sw.) and rice (Oryza sativa L.).

Seashore paspalum is a halophytic turfgrass that occupies habitats which can dramatically differ in salt concentration. Populations may …

Dynamics Of Hybrid Zones At A Continental Scale, Bradley T. Martin

Graduate Theses and Dissertations

Hybridization has traditionally been viewed as a happenstance that negatively impacts populations, but is now recognized as an important evolutionary mechanism that can substantially impact the evolutionary trajectories of gene pools, influence adaptive capacity, and contravene or reinforce divergence. Physiographic processes are important drivers of dispersal, alternately funneling populations into isolation, promoting divergence, or facilitating secondary contact of diverged populations, increasing the potential for hybridization. In North America, glacial-interglacial cycles and geomorphological changes have provided a dynamic backdrop over the last two million years that promoted such oscillations of population contraction and expansion. These biogeographic processes have resulted in regional …

Crippling Rapid Evolution Of Metastasis And Drug Resistance In A549 Non-Small Cell Lung Cancer Cells With The Clinically Relevant Hsp90 Inhibitor Auy922, Nickolas Anthony Bacon

Theses, Dissertations and Capstones

The ability for species to evolve new features in response to changing circumstances in order to survive and propagate is a ubiquitous observation on both the macroscopic and microscopic levels of living systems. It should be no surprise, then, that diseases such as cancer utilize their own forms of adaptation to perpetuate themselves when exposed to external threats. Indeed, concepts drawn from Darwinian evolution are now widely accepted to help explain certain aspects of carcinogenesis and malignant progression, the sum of which have come to be known as the theory of tumor evolution. Since metastasis and drug resistance are features …

Functional Genetic Approaches To Provide Evidence For The Role Of Toolkit Genes In The Evolution Of Complex Color Patterns In Drosophila Guttifera, Mujeeb Olushola Shittu

Dissertations, Master's Theses and Master's Reports

Toolkit genes are set of genes that orchestrate the development of basic body plan of animals, and they are highly conserved in all animals. The co-option of the toolkit genes into the pigmentation pathway has led to the evolution of novel species. This study focuses on understanding how the complex color patterns in animals develop by using the Drosophila species in the quinaria group as models. We developed an mRNA in situ hybridization (ISH) protocol, which allowed us to study gene expression patterns in the abdomen of developing pupae of non-model Drosophila species (Chapter 2). Through ISH, we found that …