Genetics and Genomics Commons^™

Tree Biomass – A Fragile Carbon Storage In Old-Growth Birch And Aspen Stands In Hemiboreal Latvia, Laura Ķēniņa, Didzis Elferts, Ieva Jaunslaviete, Endijs Bāders, Guntars Šņepsts, Āris Jansons

Aspen Bibliography

Birch (Betula pendula Roth, Betula pubescens Ehrh.) and European aspen (Populus tremula L.) stands dominate the deciduous forests of Northern Europe. Due to increasing forest protections, more deciduous stands will reach the old-growth stage. Thus, data on the carbon storage potential in such areas are essential. We aimed to establish a benchmark for carbon stocks of the main carbon pools in old-growth deciduous hemiboreal stands. Carbon pools were calculated from measurements in forty old-growth (104–148 years-old) deciduous stands in forests on fertile mineral soil. The carbon stock in these stands is distributed across tree biomass (~ 60%), mineral soil (~ …

Effects Of Riverine Barriers On Avian Evolution In The Amazon Basin, Andre Eugene Moncrieff

LSU Doctoral Dissertations

The high biodiversity found in the Amazon Basin has long captivated the attention of naturalists and evolutionary biologists seeking to explain its origins. Early observations by Alfred Wallace highlighted the role of rivers in delimiting the geographic ranges of many species; furthermore, where rivers narrow towards their headwaters, he noted that some species cross rivers freely. A major goal of this dissertation is to investigate how these and other observations about riverine barriers might inform our understanding of how speciation unfolds in Amazonia. My approach involved generating genomic data with dense geographic sampling for manakins in the genus Lepidothrix, …

Aspen Leaves As A "Chemical Landscape" For Fungal Endophyte Diversity - Can Nitrogen And Herbivory Shape The Community Composition In Controlled Conditions?, Johanna Witzell, Vicki Huizu Guo Decker, Marta Agostinelli, Carmen Romeralo Tapia, Michelle Cleary, Benedicte Riber Albrectsen

Aspen Bibliography

The endophytic microbiome may influence the ecological performance of plants, including forest trees. Various abiotic and biotic factors may shape the endophyte communities directly but also indirectly, by modifying the quality of host plants as a substrate. We hypothesized that potentially antifungal or fungistatic condensed tannins (CTs) would determine the quality of aspen (Populus tremula) leaves as a substrate for endophytic fungi. By subjecting the plants to nitrogen fertilization (N) or herbivory (H; leaf beetles) we aimed to change the internal “chemical landscape”, especially the CT levels, in aspen leaves. We expected that this would lead to changes in the …

Genetic Variation Among Populations Of, And Evidence Of Deep Divergence Within, The Rio Grande Chirping Frog, Eleutherodactylus Campi (Anura: Eleutherodactylidae), Kebede Beshera, Avery A. Williams Mr., John A. Hamlin Dr., Peter J. Bergeaux Mr., Christian C. Morgan Dr., Aubrey N. Armstrong Ms.

Faculty Publications

Herein we report the first molecular assessment of intra-species genetic variation and interrelationships within the Rio Grande Chirping frog, Eleutherodactylus campi. We analyzed 548 base pairs of 16S rRNA gene for 71 ingroup individuals belonging to the genus Eleutherodactylus (including 42 E. campi sampled from 15 localities in the United States and Mexico) and four outgroup samples. By unveiling two highly divergent and geographically structured clades within E. campi this study provides a novel phylogenetic placement of E. campi populations north and south of the Rio Grande Valley as sister groups to each other. The observed level of genetic …

Caribbean Reef-Building Coral-Symbiodiniaceae Network: Identifying Symbioses Critical For System Stability In A Changing Climate, Shaman Patel

All HCAS Student Capstones, Theses, and Dissertations

Increasing global ocean temperatures and frequency of marine heatwaves pose dire consequences for coral reefs. High temperatures often lead to disruptions in coral symbiosis resulting in coral bleaching, increasing the mortality of corals. However, corals can potentially avoid bleaching peril by associating with thermally tolerant symbionts. Here we provide a tool for understanding symbiosis network stability of Caribbean reef-building corals. We created a network of Caribbean hermatypic corals and their associated Symbiodiniaceae phylotypes. A bleaching model was applied to this network to test for resilience and robustness (R50) to thermal stress. It was also layered with trait data for coral …

Biology And Ecology Of Aedes (Stegomyia) Aegypti In The Northern Chihuahuan Desert, Adam Joseph Vera

Open Access Theses & Dissertations

Aedes aegypti is a medically important mosquito species that transmits multiple arboviruses, including dengue, chikungunya, Zika, and yellow fever. This mosquito species has expanded its geographical range into expanded into the Northern Chihuahuan Desert to further increase the risk of infection by these viruses in naïve human populations. Although Ae. aegypti is abundant along the U.S.â??Mexico border, the biology and ecology of this mosquito species in this temperate/arid climate region is not understood. The objective of this study was to understand the environmental factors that influence the invasive species of Ae. aegypti abundance, breeding habitat selection, host feeding behavior, and …

Landscape Genomics Of The Tussock Cottongrass (Eriophorum Vaginatum) And The Dwarf Birch (Betula Nana) In North Central Alaska, Elizabeth Stunz

Open Access Theses & Dissertations

Global climate change has resulted in geographic range shifts of flora and fauna at a global scale. Extreme environments, like the Arctic, are seeing some of the most pronounced changes. This region covers 14% of the Earthâ??s land area, and while many arctic species are widespread, understanding ecotypic variation at the genomic level will be important for elucidating how range shifts will affect ecological processes. Increase in shrub cover is a major effect of ongoing climate change in arctic tundra ecosystems. The relative increases in abundance and cover of shrub species such as birch, willow, and alder (Betula, Salix, and …

Potential Fitness Trade-Offs Of Elevated Esterase Activity Associated With Insecticide Resistance In The Mosquito Culex Quinquefasciatus, Timothy Schulte

Electronic Theses, Projects, and Dissertations

One of the current major issues in the control of vector-borne disease is resistance to insecticides. Resistance to one or more insecticides has appeared in over 580 different arthropod species. Widespread resistance has led to the field of Insecticide Resistance Management (IRM). The goal of IRM is to develop insecticide-use strategies that prevent or slow down the evolution of resistance. Computer models have shown that more effective IRM strategies rely on the assumption that resistance carries a fitness cost in the absence of insecticide use.

In the mosquito Culex quinquefasciatus resistance to certain organophosphate insecticides is caused by an increased …

The First Complete Genome Of The Simian Malaria Parasite Plasmodium Brasilianum, Marko Bajic, Shashidhar Ravishankar, Mili Sheth, Lori A. Rowe, M. Andreina Pacheco, Dhruviben S. Patel, Dhwani Batra, Vladimir Loparev, Christian Olsen, Ananias A. Escalante, Fredrik Vannberg, Venkatachalam Udhayakumar, John W. Barnwell, Eldin Talundzic

Harold W. Manter Laboratory of Parasitology: Library Materials

Naturally occurring human infections by zoonotic Plasmodium species have been documented for P. knowlesi, P. cynomolgi, P. simium, P. simiovale, P. inui, P. inui-like, P. coatneyi, and P. brasilianum. Accurate detection of each species is complicated by their morphological similarities with other Plasmodium species. PCR-based assays offer a solution but require prior knowledge of adequate genomic targets that can distinguish the species. While whole genomes have been published for P. knowlesi, P. cynomolgi, P. simium, and P. inui, no complete genome for P. brasilianum has …

Alu Dimorphism At The Pv92 Locus Of Chromosome 16 Is In Equilibrium For University Student Population, James M. Brooks, Mackenzie L. Thackston

Journal of the South Carolina Academy of Science

Alu is a retrotransposable element, which refers to its ability to be copied and move from one region of DNA to another DNA region. At the PV92 locus of chromosome 16, Alu is a 300 bp dimorphic insert that can either be present or absent. It does not encode a protein product and has lost the ability to transpose. It is specific to humans, and differences in genotype and allele frequencies between human populations are important tools in understanding evolution. In this research, data was obtained and analyzed from 269 students at Charleston Southern University (CSU) belonging to four different …

Morphometric And Molecular Characterization Of An Unpigmented Haemosporidian Parasite In The Neotropical Turnip-Tailed Gecko (Thecadactylus Rapicauda), Nubia E. Matta, Leydy P. González, Mario Vargas-Ramírez, Gediminas Valkiūnas, Ananias A. Escalante, M. Andreína Pacheco

Harold W. Manter Laboratory of Parasitology: Library Materials

Morphological traits from blood stages have been the gold standard for determining haemosporidian parasite species. However, the status of some taxa and the value of such traits in parasites from reptiles remain contentious. The scarce sampling of these species worsens the situation, and several taxa lack molecular data. A survey was performed in the Magdalena Department in Colombia, where 16 species of reptiles were captured. A peculiar haemosporidian parasite was found in the Turnip-tailed gecko Thecadactylus rapicauda. This haemosporidian does not show malarial pigment in blood stages under light microscopy; thus, it fits the Garnia genus’s characters belonging to …

Variability And Genetic Structure Of The Montezuma Quail Cyrtonyx Montezumae In The Northern Limit Of Its Distribution, Eduardo Sánchez Murrieta, Alberto Macías-Duarte, Reyna A. Castillo-Gámez, Angel B. Montoya, Alejandro Varela-Romero, Nohelia G. Pacheco Hoyos

National Quail Symposium Proceedings

A species’ geographic distribution of genetic variability is influenced by different factors including size of geographic distribution, dispersal capability, mating system, and migration. For instance, a low migration rate among populations may cause a decrease in genetic variation. Such is the case of the Montezuma quail (Cyrtonyx montezumae), a popular game bird with a limited flight capacity that prevents long-distance dispersal. In the northern limit of the species’ distribution in Arizona, New Mexico, and Texas in the United States, the species inhabits oak forests that are separated from one another by deserts. Consequently, Montezuma quail populations are distributed …

Ungulate Herbivores As Drivers Of Aspen Recruitment And Understory Composition Throughout Arid Montane Landscapes, Elizabeth S. Reikowski, Tyler Refsland, J. Hall Cushman

Aspen Bibliography

Herbivory by wild and domestic ungulates can influence tree recruitment and understory forest communities throughout the world. Herbivore-driven declines in tree recruitment have been observed for quaking aspen (Populus tremuloides), a foundation species whose health and management is recognized as a critical priority throughout much of its range. Livestock fencing is commonly used to promote aspen regeneration, but its effectiveness is rarely assessed, especially across large spatial scales. Using a livestock-reduction experiment, we evaluated the effects of ungulate herbivory on aspen in the Great Basin and southern Cascades, an expansive and environmentally heterogeneous region where aspen faces the …

Polymorphism & Parasites: Structure, Diversity And Selection Of The Mhcii Genes In A Weakly Electric Fish, Brachyhypopomus Occidentalis, Bruna L. Silva

Graduate Masters Theses

The major histocompatibility complex (MHC) class II molecules play a key role in inducing an immune response, by presenting foreign peptides to T-lymphocytes. They are considered one of the most polymorphic genes in the vertebrate genome and diversity has been associated with species diversification mediated by parasite, viral and bacterial infections. While MHC genes are well documented in teleost fish, none thus far have been described in the Gymnotiform order – a highly diverse group of neotropical electric fishes. Using a combination of a recently annotated genome and whole genome resequencing data, I identified and characterized both the classical MHCII …

Evaluating Non-Invasive Environmental Methods For Detecting Tropical African Pangolin Species To Inform Conservation Actions, Ichu Godwill Ichu

Theses and Dissertations

Tropical African pangolin species are threatened throughout their range due to habitat loss and illegal take. Limited knowledge on distribution has rendered conservation efforts challenging. Methods commonly used for other wildlife species need to be tested for each pangolin species as each has variable ecologies requiring specific detection and monitoring techniques. This thesis evaluates the efficacy of two non-invasive environmental methods for detecting tropical African pangolin species, and consists of two complementary studies; a proof of concept study using soil sourced eDNA from a white-bellied pangolin enclosure in the Columbus Zoo, Ohio, to detect the species, and a field study …

Chromosome Number Evolution, Phylogeography, And The Effects Of Climate Change On Species Distributions In Polyploid Plant Systems, Courtney H. Babin

LSU New Orleans Theses and Dissertations

Polyploidy, a term used to describe organisms with cells having more than two paired sets of chromosomes, is a significant driver of diversification among land plants. Over a century of research has advanced our understanding of polyploidization in some taxa, but polyploid organisms remain understudied. In this dissertation, I investigate chromosome number evolution, phylogeographic structure, genetic differentiation, and the effects of climate change on ploidy level distribution using polyploid plant systems. In the first chapter, I inferred a molecular phylogeny of Allium, an economically important genus that includes cultivated crops and ornamentals, to investigate evolutionary transitions in chromosome number …

Development Of Graphical Models And Statistical Physics Motivated Approaches To Genomic Investigations, Yashwanth Lagisetty

Dissertations and Theses (Open Access)

Identifying genes involved in disease pathology has been a goal of genomic research since the early days of the field. However, as technology improves and the body of research grows, we are faced with more questions than answers. Among these is the pressing matter of our incomplete understanding of the genetic underpinnings of complex diseases. Many hypotheses offer explanations as to why direct and independent analyses of variants, as done in genome-wide association studies (GWAS), may not fully elucidate disease genetics. These range from pointing out flaws in statistical testing to invoking the complex dynamics of epigenetic processes. In the …

Riverscape Community Genomics Of Ozark Fishes: A Comparative Framework To Infer Ecological And Evolutionary Determinants Of Genetic Diversity, Zachery D. Zbinden

Graduate Theses and Dissertations

Genetic variation is a crucial component of biodiversity and represents the variability and spatial structure of alleles within and among organisms. Evolution modulates this variability over time through mutation, selection, gene flow, and genetic drift. However, our capacity to test foundational theories of population genetics has always been at the mercy of molecular approaches available to quantify patterns of genetic diversity. Initially, techniques for empirical DNA studies were in their infancy and limited by technologies and the price per unit of genetic information. Because of these constraints, our pursuits have generally been limited to investigations of one or a few …

Coping With Environmental Constraints: Geographically Divergent Adaptive Evolution And Germination Plasticity In The Transcontinental Populus Tremuloides, Roos Goessen, Nathalie Isabel, Christian Wehenkel, Nathalie Pavy, Lisa Tischenko, Lyne Touchette, Isabelle Giguère, Marie-Claude Gros-Louis, Jérôme Laroche, Brian Boyle, Raju Soolanayakanahally, Karen E. Mock, Javier Hernández-Velasco, Sergio Leonel Simental-Rodriguez, Jean Bousquet, Ilga M. Porth

Aspen Bibliography

Societal Impact Statement

Syntheses clearly show that global warming is affecting ecosystems and biodiversity around the world. New methods and measures are needed to predict the climate resilience of plant species critical to ecosystem stability, to improve ecological management and to support habitat restoration and human well-being. Widespread keystone species such as aspen are important targets in the study of resilience to future climate conditions because they play a crucial role in maintaining various ecosystem functions and may contain genetic material with untapped adaptive potential. Here, we present a new framework in support of climate-resilient revegetation based on comprehensively understood …

Population Genetics Of Cownose Rays, Rhinoptera Spp. In The Western Atlantic, Helen Weber

Master's Theses

Using molecular tools (e.g., the NADH subunit II mitochondrial gene), this study was the first to document the Brazilian cownose ray, Rhinoptera brasiliensis, within the northwestern Atlantic (NWA), and was the first study to examine population structure in R. brasiliensis within the NWA or northern Gulf of Mexico (GMX), revealing novel insights into the population biology of the animal and extending its range by nearly 1,500 km. This study also examined the sympatrically occurring American cownose ray, R. bonasus, and found population structure between the NWA and the GMX and the NWA and the southwestern Atlantic (SWA). High …

Bee Brains: Dissecting Pollinator Behavior And The Importance Of Plasticity In The Face Of Changing Environments, Rachel Brant

Dissertations

All organisms face environmental variability, and much of contemporary biological research aims to understand the mechanisms allowing organisms to adapt and survive in the face of change. Animals residing in urban habitats face particularly high levels of unpredictability and environmental fluctuation due to changes based upon human desire. Though urban areas are considered relatively novel habitats, numerous species have adapted to city life, mediated through behavioral and physiological plasticity. Native bee species show particularly high species richness and abundance in urban settings, but the mechanisms driving this pattern are poorly understood. In this dissertation, I explore how bees employ plasticity …

Insights Into The Speciation Process From Genomic And Phenotypic Analysis Of An Avian Hybrid Zone In Amazonia, Glaucia Christina Del-Rio

LSU Doctoral Dissertations

Understanding the outcome of secondary contact is essential to shed light on the mechanisms governing species formation and maintenance. In Amazonia, closely related bird taxa with limited dispersal abilities are often separated by rivers, which presumably act as dispersal barriers. However, at the headwaters, rivers cease to be dispersal barriers, and this generates opportunities for secondary contact. In my dissertation, I studied genomic mechanisms associated with phenotypic differences, mitochondrial DNA structure, and putative reproductive barriers between two hybridizing Amazonian bird species in the genus Rhegmatorhina, a group of antbirds that find their arthropod prey exclusively by following army-ant swarms. …

Plastic And Evolved Responses In The Eastern Oyster, Crassostrea Virginica, To Environmental Variation In The Northern Gulf Of Mexico, Kyle Sirovy

LSU Doctoral Dissertations

Climate change and other anthropogenic impacts are causing rapid alterations to many of the world’s most productive coastal ecosystems and there is an urgent need to understand how species will respond to these environmental changes. Organisms may respond through plasticity, evolution, or the evolution of plasticity. In this dissertation, I evaluate the role of plastic and evolved responses in the eastern oyster, Crassostrea virginica, to environmental variation in the northern Gulf of Mexico. I use comparative transcriptomics, physiology, and morphology to examine the relative contribution of plastic and evolved responses for oysters exposed to low salinity and outplant sites …

Growing Space Management In Boreal Mixedwood Forests: 22 Year Results, Richard Kabzems, George Harper, Che Elkin

Aspen Bibliography

Boreal mixed forests of trembling aspen (Populus tremuloides) and white spruce (Picea glauca) can provide higher outputs of many ecosystem goods and services, combined with resilience for changing environmental conditions. In this study, we examine the growth of white spruce and aspen over a range of stand compositions created by spot and broadcast treatments of broadleaves using manual and chemical means, aspen spacing, and untreated control. Twenty-two growing seasons postharvest, treatment responses created a range of broadleaf densities and spatial arrangements, reflected in significant differences in heights and diameters of the spruce mixedwood component. At this …

Population Genomics Of The Giant Caribbean Sea Anemone Condylactis Gigantea (Anthozoa: Actiniidae) In Florida And Across The Caribbean, Nancy E. Sheridan

USF Tampa Graduate Theses and Dissertations

The giant Caribbean sea anemone Condylactis gigantea is a long-lived, conspicuous, and phenotypically diverse species native to the western Atlantic Ocean (from Bermuda to southeast Brazil), Caribbean Sea, and southeastern Gulf of Mexico. This sea anemone is an important benthic community member that provides habitat to numerous species, including cleaner shrimp. This relationship makes these animals desirable to aquarists for both enjoyment and the service provided by the shrimp for the overall health of an aquarium, and which is why they are sought.

The extraction of about 3.3 million C. gigantea individuals in Florida over a 23-year period for the …

Recovery Of Trembling Aspen, Tamarack, And White Spruce Seedlings From Nacl Stress Following Winter Dormancy: Implications For Increased Foliar Potassium, Necrosis, And Sodium Management As Stress Resistance Mechanisms, Nathan T. Lauer

Aspen Bibliography

Revegetation of boreal forest lands disturbed by surface mining for bitumen can be challenging due to fluctuating levels of soil NaCl and harsh winter temperatures. These stressors may hinder the growth and survival of planted tree seedlings. Two experiments were carried out to examine the processes of recovery from NaCl stress and overwintering in trembling aspen, tamarack, and white spruce seedlings. In the recovery experiment, seedlings were treated with 0, 50, or 100 mM NaCl for 60 days and then allowed to recover for 60 days. Most of the examined physiological variables (total dry weight, chlorophyll concentration, photosynthesis, and transpiration) …

Characterizing Endogenous Dicer Products To Unravel Novel Rnai Biogenesis Pathways, Jacob Oche Peter

Dissertations

ABSTRACT

RNA interference (RNAi) is a pervasive gene regulatory mechanism in eukaryotes based on the action of multiple classes of small RNA (sRNA). Exploiting RNAi pathways in non-model systems have great potential for creating potent RNAi technologies. Here, we accessed RNAi-mediated control of gene expression in the two-spotted spider mite, Tetranychus urticae (T. urticae) using engineered dsRNA designed to modulate the host RNAi pathway and increase RNAi efficacy. Analysis of Dicer (Dcr) generated fragments revealed how exogenous RNAs access the host RNAi pathway in this animal, opening avenues for designing RNAi technology for their control. Further, some organisms …

Compensatory Phenolic Induction Dynamics In Aspen After Aphid Infestation, Rajarshi Kumar Gaur, Ilka Nacif De Abreu, Benedicte Riber Albrectsen

Aspen Bibliography

Condensed tannins (CTs) are polyphenolics and part of the total phenolic (TP) pool that shape resistance in aspen (Populus tremula). CTs are negatively associated with pathogens, but their resistance properties against herbivores are less understood. CTs shape resistance to pathogens and chewing herbivores and could also shape resistance to aphids. Being chemical pools that are highly variable it can further be questioned whether CT-shaped resistance is better described by constitutive levels, by the induced response potential, or by both. Here, aspen genotypes were propagated and selected to represent a range of inherent abilities to produce and store foliar …

Genomic Insights Into Mechanisms Of Microbial Evolution And Evolution-Inspired Strategies To Combat Pathogen Diversity, Saymon Akther

Dissertations, Theses, and Capstone Projects

We live in an era of emerging infectious diseases that are increasingly common, rapidly spreading, and gravely devastating. Lyme disease, caused by bacteria belonging to the genus Borreliella, is rapidly rising in the Northern Hemisphere because of geographic range expansion of both the tick vectors and the pathogens. Evolutionary comparative analysis of Borreliella genomes is a key to understanding the phylogeographic history and mechanisms of their global diversification. Moreover, genomic variations in Borreliella associated with human pathogenicity, e.g., at loci encoding cell-surface antigens interacting with the vertebrate hosts, have not been fully identified. Similarly, the ongoing COVID-19 pandemic, caused …

A Tale Of Two Genomes: The Complex Interplay Between The Mitochondrial And The Nuclear Genomes, Abhilesh S. Dhawanjewar

School of Biological Sciences: Dissertations, Theses, and Student Research

Mitochondria, the product of an ancient endosymbiotic event are pivotal to eukaryotic cells by synthesizing the majority of the cell’s ATP output. However, modern- day mitochondria are completely dependent on more than one thousand nuclear-encoded products for their function and the maintenance of their genomes. The fundamentally different ways in which the mitochondrial (mtDNA) and the nuclear (nucDNA) genomes are replicated and inherited lead to captivating coevolutionary dynamics between them. The aims of this dissertation are to investigate the coevolutionary dynamics between the mitochondrial and nuclear genomes at three distinct biological scales. At the organismal level, we use a Drosophila …