Life Sciences Commons^™

Mitonuclear Mismatch Is Associated With Increased Male Frequency, Outcrossing, And Male Sperm Size In Experimentally-Evolved C. Elegans, Brent William Bever

Dissertations and Theses

We provide the first controlled study of how male frequencies and rates of outcrossing evolve in response to mitonuclear mismatch by allowing replicate lineages of C. elegans nematodes containing either mitochondrial or nuclear mutations of electron transport chain (ETC) genes to evolve under three sexual systems: facultatively outcrossing (wildtype), obligately selfing, and obligately outcrossing. In partial support of a tenet of the mitonuclear sex hypothesis, which predicts that outcrossing will be favored in cases of mitonuclear mismatch, we found evolution of increased male frequency in at least one replicate line of all four ETC mutant backgrounds tested--nuclear isp-1, mitochondrial …

Accumulation And Transmission Dynamics Of A Naturally-Occurring Mtdna Deletion In Caenorhabditis Briggsae, Jennifer Anne Sullins

Dissertations and Theses

Maintaining mitochondrial genome sequence integrity is essential for preserving normal mitochondrial function. Several human diseases have been associated with heteroplasmic mitochondrial genome mutations, but few genetic systems can simultaneously represent pathogenic mitochondrial genome evolution and inheritance. The nematode Caenorhabditis briggsae is one such model. Natural C. briggsae isolates are globally-distributed and phylogenetically grouped into three distinct clades, with isolates exhibiting varying levels of a large-scale mtDNA deletion, nad5∆. Furthermore, a small subset of clade II isolates exhibits putative compensatory mutations that may reduce the risk of deletion formation and accumulation in those populations. In this thesis, the author characterizes the …

Impact Of Suburban Landscape Features On Gene Flow Of The Model Invasive Grass, Brachypodium Sylvaticum, Tina Marie Arredondo

Dissertations and Theses

Rapid range expansion of newly invasive species provides a unique opportunity for studying patterns of dispersal and gene flow. In this thesis, I examined the effect of landscape features on gene flow in the invasive grass Brachypodium sylvaticum at the edge of its expanding range. I used genome-wide Single Nucleotide Polymorphism (SNP) surveys of individuals from 22 locations in the Clackamas Watershed in the Portland, Oregon metropolitan region to assess genetic diversity and structure, to identify putative source populations, and to conduct landscape genetic analyses. Resistance surfaces were created for each landscape feature, using ResistanceGA to optimize resistance parameters. My …

Comparative Genetic And Genomic Analysis Of The Novel Fusellovirus Sulfolobus Spindle-Shaped Virus 10, David Andrew Goodman

Dissertations and Theses

Viruses that infect thermophilic Archaea are unique in both their structure and genetic makeup. The lemon-shaped fuselloviruses - which infect members of the order Sulfolobales, growing optimally at 80º C and pH 3 - are some of the most ubiquitous and best studied viruses of the thermoacidophilic Archaea. They provide a malleable and useful genetic tool for probing into the functions of their host, as well as the host responses to infection. Nonetheless, much about these viruses remains to be learned to further understand their morphological, genetic, and life cycle characteristics.

In order to investigate these aspects of these …

Completion Of Dna Replication In Escherichia Coli, Brian Michael Wendel

Dissertations and Theses

To maintain genomic integrity, all cells must accurately duplicate their genetic material in order to provide intact and complete copies to each daughter cell following cell division. Successful inheritance of chromosomal information without changing even a single nucleotide requires accurate and robust DNA replication. This requires that cells tightly control replication initiation from the origin(s), processive elongation of the replisome, and the completion of DNA replication by resolving convergent replication forks ensuring that each sequence is duplicated without alteration. Unlike initiation and elongation, the process by which replication forks converge and are resolved into two discrete, inheritable DNA molecules is …

Investigating The Role Of Genomic Variation In Susceptibility To Environmental Chemicals Across Populations, Lindsay Adrian Holden

Dissertations and Theses

No two individuals are identical. This is true at the genetic level and at the phenotypic level. One of the traits that varies between populations is toxicant susceptibility: some individuals are sensitive to the effects of environmental chemical exposure, and others are resistant. This body of work aims to address the impact of genomic copy number variants (CNV)--large (>1 Kb) duplications or deletions across the genome--on the toxicant-susceptibility phenotype.

Herein copy number variants were characterized across three commonly used laboratory strains of zebrafish (Danio rerio) and mRNA expression phenotypes were identified in the same strains. It was found that …

Transcriptomic Regulation Of Alternative Phenotypic Trajectories In Embryos Of The Annual Killifish Austrofundulus Limnaeus, Amie L. Romney

Dissertations and Theses

The Annual Killifish, Austrofundulus limnaeus, survives the seasonal drying of their pond habitat in the form of embryos entering diapause midway through development. The diapause trajectory is one of two developmental phenotypes. Alternatively, individuals can "escape" entry into diapause and develop continuously until hatching. The alternative phenotypes of A. limnaeus are a form of developmental plasticity that provides this species with a physiological adaption for surviving stressful environments. The developmental trajectory of an embryo is not distinguishable morphologically upon fertilization and phenotype is believed to be influenced by maternal provisioning within the egg based on observations of offspring phenotype …

Investigating The Origin And Functions Of A Novel Small Rna In Escherichia Coli, Fenil Rashmin Kacharia

Dissertations and Theses

Non-coding small RNAs (sRNAs) regulate various cellular processes in bacteria. They bind to a chaperone protein Hfq for stability and regulate gene expression by base-pairing with target mRNAs. Although the importance of sRNAs in bacteria has been well established, the mode of origination of novel sRNA genes is still elusive, mainly because the rapid rate of evolution of sRNAs obscures their original sources. To overcome this impediment, we identified a recently formed sRNA (EcsR2) in E. coli, and show that it evolved from a degraded bacteriophage gene. Our analyses also revealed that young sRNAs such as EcsR2 are expressed …

Investigating The Effects Of 17Α-Ethynylestradiol On Mitochondrial Genome Stability, Alicia M. Chivers

Dissertations and Theses

Environmental toxicants are ubiquitous throughout the environment as a result of human activity. Among these toxicants, environmental estrogens are a category of particular concern due to their environmental prevalence and potency in altering reproductive traits. While many studies have addressed the detrimental effects of environmental estrogens on both aquatic and terrestrial organisms, few have analyzed the potential for these compounds to alter mitochondrial function. Mitochondria are the primary energy-generating system for all eukaryotic life, supporting all aspects of development, metabolism, and growth. Each cell within the body contains many mitochondria which in turn contain multiple copies of their own DNA …

The Foundations Of Network Dynamics In An Rna Recombinase System, Jessica Anne Mellor Yeates

Dissertations and Theses

How life originated from physical and chemical processes is one of the great questions still unanswered today. Studies towards this effort have transitioned from the notion of a single self-replicating entity to the idea that a network of interacting molecules made this initial biological leap. In order to understand the chemical kinetic and thermodynamic mechanisms that could engender pre-life type networks we present an empirical characterization of a network of RNA recombinase molecules. We begin with 1-, 2-, and 3-molecular ensembles and provide a game theoretic analysis to describe the frequency dependent dynamics of competing and cooperating RNA genotypes. This …

Mechanisms Of Adaptation In The Newly Invasive Species Brachypodium Sylvaticum (Hudson) Beauv., Gina Lola Marchini

Dissertations and Theses

It is common knowledge that invasive species cause worldwide ecological and economic damage, and are nearly impossible to eradicate. However, upon introduction to a novel environment, alien species should be the underdogs: They are present in small numbers, possess low genetic diversity, and have not adapted to the climate and competitors present in the new habitat. So, how are alien species able to invade an environment occupied by native species that have already adapted to the local environment? To discover some answers to this apparent paradox I conducted four ecological genetic studies that utilized the invasive species Brachypodium sylvaticum (Hudson) …

Developmental Mechanisms That Support Genome Stability And Embryonic Survival In Stress-Tolerant Embryos Of The Annual Killifish Austrofundulus Limnaeus, Josiah Tad Wagner

Dissertations and Theses

In order to complete their life cycles, vertebrates require oxygen and water. However, environments are not always forgiving when it comes to constantly providing these basic needs for vertebrate life. The annual killifish Austrofundulus limnaeus is possibly the most well described extremophile vertebrate and its embryos have been shown to tolerate extremes in oxygen, salinity, and water availability. This phenotype is likely a result of the annual killifish life history, which includes periods of temporary habitat desiccation and oxygen deprivation, and requires the production of stress-tolerant embryos that depress metabolism in a state of suspended animation, known as diapause. Over …

Investigating A Role For The Ccaat/Enhancer-Binding Protein Δ In The Developing Zebrafish, Alisha Jennifer Beirl

Dissertations and Theses

The CCAAT/enhancer-binding protein delta (C/EBPδ) is a highly conserved transcription factor capable of regulating numerous cell fate processes, such as cell growth, differentiation, proliferation and apoptosis. C/EBPδ is inducible during cellular stress responses, including inflammation and responses to growth factor deprivation or thermal stress. C/EBPδ is stress-inducible in a diversity of fishes, including the zebrafish Danio rerio; however, little is known about its role in fish development. Here I show that overexpression of C/EBPδ leads to severe developmental defects, including reduced body length, edema, liver malformation and retinal abnormalities. The proportion of individuals that display developmental abnormalities is significantly …

The Boiling Springs Lake Metavirome: Charting The Viral Sequence-Space Of An Extreme Environment Microbial Ecosystem, Geoffrey Scott Diemer

Dissertations and Theses

Viruses are the most abundant organisms on Earth, yet their collective evolutionary history, biodiversity and functional capacity is not well understood. Viral metagenomics offers a potential means of establishing a more comprehensive view of virus diversity and evolution, as vast amounts of new sequence data becomes available for comparative analysis.
Metagenomic DNA from virus-sized particles (smaller than 0.2 microns in diameter) was isolated from approximately 20 liters of sediment obtained from Boiling Springs Lake (BSL) and sequenced. BSL is a large, acidic hot-spring (with a pH of 2.2, and temperatures ranging from 50°C to 96°C) located in Lassen Volcanic National …

Gene Expression Life History Markers In A Hatchery And A Wild Population Of Young-Of-The-Year Oncorhynchus Mykiss, Ian D. F. Garrett

Dissertations and Theses

Life history within a single species can vary significantly. Many of these differences are associated with varying environmental conditions. Understanding what environmental conditions cue alternate life histories within a single species has been researched extensively. In salmonid fishes, more than almost any other group, varying environmental conditions give rise to individuals within species that take markedly different life history trajectories.

Oncorhynchus mykissis a species of salmonid native to the Pacific Northwest region of North America. This species has two life history forms, anadromous and resident. The anadromous form spends a portion of its life in ocean while the resident life …

An Evaluation Of The Nontarget Effects Of Transgenic Bacillus Thuringiensis Maize On Arbuscular Mycorrhizal Fungi In The Soil Ecosystem, Tanya Elizabeth Amy Cheeke

Dissertations and Theses

My dissertation research examined the effect of the cultivation of insect-resistant Bacillus thuringiensis (Bt) maize on the soil environment with a goal of understanding how to obtain a balance between technological advancement and maintenance of a healthy soil ecosystem. Although Bt plants may help to reduce pesticide use, conferring benefits to farm workers and the environment, there are still unresolved questions about how the cultivation of Bt plants affects soil organisms. For this dissertation project, I used 14 different genotypes of Bt maize and non-Bt maize (Zea mays) to investigate the effects of transgenic Bt plants on the colonization ability, …

Effects Of Reactive Oxygen Species On Life History Traits Of Caenorhabditis Elegans, Samson William Smith

Dissertations and Theses

Evolutionary life history theory predicts that tradeoffs among fitness-related phenotypes will occur as a result of resource limitations and/or physiological constraints. Such tradeoffs are defined as the cost(s) incurred on one component of fitness (e.g., reproduction) by the increased expression of another fitness-related trait (e.g., longevity). Only recently have researchers begun to investigate the mechanistic bases of life history tradeoffs. A recent proposal is that reactive oxygen species (ROS) have a central role in shaping life history traits and tradeoffs. Research on disparate animal taxa has highlighted strong correlations between oxidative stress resistance and fitness-related life history traits, for example. …

Causes And Consequences Of Mitochondrial Variation In Caenorhabditid Nematodes, Kiley Ann Hicks

Dissertations and Theses

Mitochondria are dynamic organelles that harbor their own stream-lined genome and generate much of the ATP necessary to sustain eukaryotic life via an electron transport chain (ETC). Because of the central role for mitochondria in organismal physiology, mitochondrial genetic and phenotypic variation can alter organismal fitness and affect population genetic and evolutionary outcomes. Despite the far-reaching relevance of mitochondria to evolutionary processes and human health, we lack a basic understanding of the causes and consequences of mitochondrial genetic and phenotypic variation. In this thesis, I quantified mitochondrial reactive oxygen species (ROS), membrane potential (δΨM), and mitochondrial morphological traits within Caenorhabditis …

Analysis Of Mitochondrial Dna Restriction Fragment Patterns In Killer Whales, Orcinus Orca, Tracy Alison Stevens

Dissertations and Theses

The mitochondrial DNA restriction fragment patterns of killer whales (Orcinus orca) were investigated in order to determine the level of genetic differentiation that exists between killer whales from various geographic locations. Twenty one killer whales were examined, seventeen of which were captive killer whales that originated from the North Atlantic and Northeast Pacific Oceans. Two were captive-born animals and two were killer whales that stranded along the Northeast Pacific coast.

DNA was extracted from blood and/or tissue samples, cleaved with a variety of restriction endonucleases and the DNA fragments were separated by horizontal agarose gel electrophoresis. The DNA …

Double Cross: Agriculture And Genetics, 1930 To 1960, Tracy Scott Lebenzon

Dissertations and Theses

This paper discusses the role of genetic technology and application in agriculture between 1930 and 1960. Topics covered include the role of genetics and the relationship that theory, education, administration, professionalism, economic and social considerations bore to genetics.

Gibbon Classification : The Issue Of Species And Subspecies, Erin Lee Osterud

Dissertations and Theses

Gibbon classification at the species and subspecies levels has been hotly debated for the last 200 years. This thesis explores the reasons for this debate. Authorities agree that siamang, concolor, kloss and hoolock are species, while there is complete lack of agreement on lar, agile, moloch, Mueller's and pileated. The disagreement results from the use and emphasis of different character traits, and from debate on the occurrence and importance of gene flow.

Molecular Cloning Of Spinach Chloroplast Dna Isolated By Alkaline Lysis, Robert Gray Drager

Dissertations and Theses

Chloroplast genomes of land plants show conservation of structure and gene arrangement. The spinach chloroplast genome is comprised of a covalently closed. circular DNA molecule of 150 kilobases and is typical of these plants. Approximately 20% of the proteins found in the spinach chloroplast are encoded by the chloroplast genome and translated on chloroplast ribosomes. The remainder are encoded on chromosomes in the nucleus, translated on cytoplasmic ribosomes and transported into the chloroplast.

Spinach chloroplast DNA was isolated from crude 2 chloroplast preparations by a new method. Chloroplasts were lysed with alkaline sodium dodecyl sulfate, contaminating macromolecules precipitated with acidified …

Restriction Mapping And Expression Of Recombinant Plasmids Containing The Arsenic Resistance Genes Of The Plasmid R45, Terry M. Coons

Dissertations and Theses

The trivalent (arsenite) and pentavalent (arsenate) forms of arsenic are introduced into the environment through the use of arsenic in herbicides, pesticides, fertilizers, and the smelting of arsenic-bearing ores. Bacteria resistant to arsenic are readily isolated from surface waters, sewage, and clinical infections. Although some bacterial resistance is provided by inducible phosphate transport systems that discriminate against arsenate, marked resistance is carried on bacterial plasmids.

A 6.9 kilobase fragment previously derived from one such plasmid, R45, and containing the genes for inducible resistance to arsenite and arsenate was ligated into the cloning vectors puce and pUC9 in opposite orientations and …

Audiological Characteristics Of The Monge Family Of Costa Rica, Christine Moulton

Dissertations and Theses

The audiological characteristics of the Monge family of Costa Rica were investigated in a sample of fifty-two affected members and twelve unaffected members. Through laboratory analysis by staff personnel from the University of Costa Rica and audiological test results obtained in the present investigation, it was concluded that affected Monge members demonstrate a slowly progressive low frequency sensorineural hearing loss of autosomal dominant transmission. The initial site of lesion appears to be the apical portion of the cochlea, with significant onset occurring during early childhood following normal speech and language acquisition. The rate at which the hearing loss progresses and …

Origin Of Human Trisomy 21 Mosaicism, Diane Dusenbery Waggoner

Dissertations and Theses

Down Syndrome is a human condition caused by an extra copy of a #21 chromosome. At least one to two percent of free (not translocated) trisomy 21 cases are mosaics, i.e., they have two or more distinct cell lines. Usually, one cell line is 47 ,XX or XY ,+21 while the other cell line is normal 46,XX or 46,XY.

The purpose of the study was to establish the etiologies of the separate cell lines by determining whether the zygote was trisomic or normal. Meiotic non-disjunction in the formation of a gamete could lead to a trisomic zygote; loss of a …

Cytologic Characterization Of Human Constitutive Heterochromatin, Timothy Atchison Donlon

Dissertations and Theses

A study was conducted to cytologically map certain subsets of constitutive heterochromatin onto specific portions of human chromosomes. This involved sequentially staining metaphase chromosomes from lymphocytes first with the Centromeric Dot, Giemsa-11, G-banding or Lateral Asymmetry staining techniques, which are cytochemical methods which stain particular chromosomes or chromosomal regions. Then those same metaphase chromosomes were stained using the C-banding technique, a method which is believed to denote constitutive heterochromatin. With the exception of the G-banding technique, areas depicted by the special staining techniques were found to reside only within the areas stained by the C-band technique and are thus believed …

An Analysis Of Staggered Spondaic Word Test Performances Of Dyslexic Children And Their Parents, Nancy Jane Maxwell

Dissertations and Theses

The purpose of this study was to investigate the possibility of a familial lineage for dyslexia by analyzing certain auditory processing characteristics of dyslexic children and their parents. The Staggered Spondaic Word test was administered to twenty-one dyslexic children, eight to thirteen years of age, their natural parents and normal reading siblings.

The experimental test data were tabulated and analyzed according to listening condition for each of the four groups: dyslexic children, normal reading siblings, affected parents and non-affected parents. A statistical analysis of the experimental data revealed significantly poorer Staggered Spondaic Word test performances for dyslexic children and their …

A Test Of The Simple Recessive Hypothesis For The Inability To Taste Phenyl-Thio-Urea: A Family Study, Susan I. Wolf

Dissertations and Theses

This thesis is a report on the analysis of family data gathered to test the simple recessive hypothesis for the inability to taste phenyl-thio-urea (P.T.C.). The simple recessive hypothesis states that the inability of a minority of persons to taste high concentrations of P.T.C. is due to the action of an autosomal recessive gene in the homozygous condition.