Genetics and Genomics 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 …

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 …

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) …

Cryptic Diversity And Discordance In Single‐Locus Species Delimitation Methods Within Horned Lizards (Phrynosomatidae: Phrynosoma), Christopher Blair, Robert W. Bryson Jr.

Publications and Research

Biodiversity reduction and loss continues to progress at an alarming rate, and thus there is widespread interest in utilizing rapid and efficient methods for quantifying and delimiting taxonomic diversity. Single-locus species-delimitation methods have become popular, in part due to the adoption of the DNA barcoding paradigm. These techniques can be broadly classified into tree-based and distance-based methods depending on whether species are delimited based on a constructed genealogy. Although the relative performance of these methods has been tested repeatedly with simulations, additional studies are needed to assess congruence with empirical data. We compiled a large data set of mitochondrial ND4 …

Prebiotic Rna Network Formation: A Taxonomy Of Molecular Cooperation, Cole Mathis, Sanjay N. Ramprasad, Sara Imari Walker, Niles Lehman

Chemistry Faculty Publications and Presentations

Cooperation is essential for evolution of biological complexity. Recent work has shown game theoretic arguments, commonly used to model biological cooperation, can also illuminate the dynamics of chemical systems. Here we investigate the types of cooperation possible in a real RNA system based on the Azoarcusribozyme, by constructing a taxonomy of possible cooperative groups. We construct a computational model of this system to investigate the features of the real system promoting cooperation. We find triplet interactions among genotypes are intrinsically biased towards cooperation due to the particular distribution of catalytic rate constants measured empirically in the real system. For other …

A Polyglot Approach To Bioinformatics Data Integration: A Phylogenetic Analysis Of Hiv-1, Steven Reisman, Thomas Hatzopoulos, Konstantin Laufer, George K. Thiruvathukal, Catherine Putonti

Konstantin Läufer

As sequencing technologies continue to drop in price and increase in throughput, new challenges emerge for the management and accessibility of genomic sequence data. We have developed a pipeline for facilitating the storage, retrieval, and subsequent analysis of molecular data, integrating both sequence and metadata. Taking a polyglot approach involving multiple languages, libraries, and persistence mechanisms, sequence data can be aggregated from publicly available and local repositories. Data are exposed in the form of a RESTful web service, formatted for easy querying, and retrieved for downstream analyses. As a proof of concept, we have developed a resource for annotated HIV-1 …

A Polyglot Approach To Bioinformatics Data Integration: A Phylogenetic Analysis Of Hiv-1, Steven Reisman, Thomas Hatzopoulos, Konstantin Laufer, George K. Thiruvathukal, Catherine Putonti

Catherine Putonti

As sequencing technologies continue to drop in price and increase in throughput, new challenges emerge for the management and accessibility of genomic sequence data. We have developed a pipeline for facilitating the storage, retrieval, and subsequent analysis of molecular data, integrating both sequence and metadata. Taking a polyglot approach involving multiple languages, libraries, and persistence mechanisms, sequence data can be aggregated from publicly available and local repositories. Data are exposed in the form of a RESTful web service, formatted for easy querying, and retrieved for downstream analyses. As a proof of concept, we have developed a resource for annotated HIV-1 …

Clusters Of Alpha Satellite On Human Chromosome 21 Are Dispersed Far Onto The Short Arm And Lack Ancient Layers, William Ziccardi, Chongjian Zhao, Valery Shepelev, Lev Uralsky, Ivan Alexandrov, Tatyana Andreeva, Evgeny Rogaev, Christopher Bun, Emily Miller, Catherine Putonti, Jeffrey Doering

Catherine Putonti

Human alpha satellite (AS) sequence domains that currently function as centromeres are typically flanked by layers of evolutionarily older AS that presumably represent the remnants of earlier primate centromeres. Studies on several human chromosomes reveal that these older AS arrays are arranged in an age gradient, with the oldest arrays farthest from the functional centromere and arrays progressively closer to the centromere being progressively younger. The organization of AS on human chromosome 21 (HC21) has not been well-characterized. We have used newly available HC21 sequence data and an HC21p YAC map to determine the size, organization, and location of the …

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 …

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 …

Genetic Demography At The Leading Edge Of The Distribution Of A Rabies Virus Vector, Antoinette J. Piaggio, Amy L. Russell, Ignacio A. Osorio, Alejandro J. Ramirez, Justin W. Fischer, Jennifer L. Neuwald, Annie E. Tibbels, Luis Lecuona, Gary F. Mccracken

Amy L. Russell

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 …

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 …

Software Development For Genome Sequence Analysis, David Farr

Symposium Of University Research and Creative Expression (SOURCE)

The cost of genome sequencing has decreased rapidly, expanding availability for many biological applications (Muir 2016). For example, researchers can now obtain genome sequences from multiple populations under different types of selection. Comparison of these sequences allows for identification of chromosome regions and specific genes associated with adaptive evolution (Kelly 2013). As an increasing number of researchers engage in this type of inquiry, many have created in-house computer scripts to analyze the raw sequence data (e.g., Kelly 2013), creating a gap in both continuity and standardization.

Using a test dataset and preliminary results from an ongoing artificial selection experiment in …

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 …

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 …

Does Genotype Correlate With Phenotype? Evaluating Ruffed Lemur (Varecia Spp.) Color Vision Using Subject Mediated Automatic Remote Testing Apparatus (Smarta), Raymond Vagell

Theses and Dissertations

Ruffed lemur (Varecia spp.) color vision research was conducted using a multidisciplinary approach: psychophysics, genetic analysis, technology, and animal training. The behavioral manifestation of Varecia spp. trichromacy was shown using a touchscreen apparatus (SMARTA). Trichromats performed better than dichromats when discriminating red from green (G₂ = 78.10, p < 0.001).

Systematics, Diversification, And Functional Diversity Of Russulaceae (Russulales), Brian Patrick Looney

Doctoral Dissertations

The family Russulaceae is an iconic family of mushroom-forming Basidiomycetes both because of their importance as edible mushrooms in many parts of the world and their species richness in both temperate and tropical forested biomes. While much mycological research has been focused on this group, recent systematic and ecological research has failed to develop a comprehensive or cohesive organization by which to understand the evolutionary relationships, patterns of diversification, or functional importance of the group. Recently, interest in ectomycorrhizal fungi (EmF), of which Russulaceae is a key lineage, has greatly increased due to the recognition of the importance of EmF …

Ecological And Evolutionary Dynamics Of Plant-Soil Feedbacks: Influences On Evolution And Range Dynamics, Michael E. Van Nuland

Doctoral Dissertations

Plants interact with, modify, and are affected by their soil environments. Though plant-soil interactions are well known to be important and active regulators of ecosystem function and community structure, much less is known about how these interactions affect plant evolution. The primary goal of my dissertation was to examine plant-soil interactions under a range of ecological and evolutionary contexts to better understand patterns of biodiversity, ecosystem function, and whole system responses to environmental change. Taking such an eco-evolutionary perspective allows for a holistic understanding of the causes and consequences of complex abiotic and biotic interactions that link ecosystem ecology and …

Using Phylogenetic Comparative Methods To Understand Diversification And Geographic Range Evolution, Kathryn Aurora Massana

Doctoral Dissertations

Two key processes that have been modeled in a phylogenetic comparative framework are diversification and historical biogeography. Many questions arise on what process have shaped the abundance (or lack) of species we see today and what influences their survival and interconnectedness with other species. Many methods have been developed to answer these questions. Over the past several decades there has been a rise in parametric modeling and development of more adequate frameworks to answer biological questions of interest. However, many models still lack the incorporation of ecological, mainly biotic factors, which influence the evolution and ecology of species, while accounting …

Investigating The Genetic Basis For Hominoid Taillessness, Samantha M. Tickey-Mccrane, Holly Dunsworth, Johanna E. Wegener

Senior Honors Projects

Investigating the Genetic Basis for Hominoid Taillessness:

A Comparative Genetic Approach Across Ten Catarrhine Taxa

Samantha Tickey-McCrane1,2, Johanna E. Wegener2, and Holly Dunsworth1

Honors Thesis Abstract Written by Samantha Tickey-McCrane, Departments of Anthropology & Biology

Advisor: Dr. Holly Dunsworth, Department of Anthropology

How did hominoid tail loss occur? My goals are to test phylogenetic and adaptive hypotheses for tail length variation among macaques, and use those insights to reconstruct the evolution of hominoid taillessness. Further, I aim to ultimately uncover which candidate genes or pathways may be responsible for catarrhine tail loss, and what other traits may be affected by …

Phylogenetic Studies Of The Madagascan Freshwater Crabs (Potamoidea, Potamonautidae, Deckeniinae), Rainee Stevens

All NMU Master's Theses

Relationships within the Madagascan freshwater crab fauna were examined based on unstudied specimens from all parts of Madagascar. This study allowed the examination of the validity of existing genera and species, and identified potential new taxa. The new specimens provided phylogenetic and evolutionary data, as well as new insights into the distribution patterns of the Malagasy freshwater crab fauna. In addition, the large number of new localities from previously unsurveyed areas of Madagascar allowed the construction of updated distribution maps.

The present analysis included 62 unidentified specimens plus 13 identified species of Malagasy freshwater crab taxa that had already been …

Patterns Of Morphological And Molecular Evolution In The Antillean Tree Bat, Ardops Nichollsi (Chiroptera: Phyllostomidae), Roxanne J. Larsen, Peter A. Larsen, Caleb D. Phillips, Hugh H. Genoways, Gary G. Kwiecinski, Scott C. Pedersen, Carleton J. Phillips, Robert J. Baker

University of Nebraska State Museum: Mammalogy Papers

Species endemic to oceanic islands offer unique insights into the mechanisms underlying evolution and have served as model systems for decades. Often these species show phenotypic variation that is correlated with the ecosystems in which they occur and such correlations may be a product of genetic drift, natural selection, and/or environmental factors. We explore the morphologic and genetic variation within Ardops nichollsi, a species of phyllostomid bat endemic to the Lesser Antillean islands. Ardops nichollsi is an ideal taxon to investigate the tempo of evolution in Chiroptera, as it: is a recently derived genus in the family Phyllostomidae; contains …

Taxonomic Placement Of The Nidulariaceae Of Nebraska And Iowa Based On Molecular And Morphological Data, Goodmond H. Danielsen Iv

UNO Student Research and Creative Activity Fair

Proper taxonomic and molecular study is necessary to better organize closely related species that may not only be used for human needs, but also in the quest for knowledge of how the world around us works. Though important, the taxonomic placement of Nebraskan and Iowan bird’s nest fungi (Nidulariaceae) is not well documented. Here, phylogenetic analysis is used to place the Nidulariaceae of Nebraska and Iowa in the tree of life using molecular and morphological techniques. Based on these results and results of further work done on these specimens, it will be possible to better place the Nidulariaceae of Nebraska …

A Polyglot Approach To Bioinformatics Data Integration: A Phylogenetic Analysis Of Hiv-1, Steven Reisman, Thomas Hatzopoulos, Konstantin Laufer, George K. Thiruvathukal, Catherine Putonti

George K. Thiruvathukal

As sequencing technologies continue to drop in price and increase in throughput, new challenges emerge for the management and accessibility of genomic sequence data. We have developed a pipeline for facilitating the storage, retrieval, and subsequent analysis of molecular data, integrating both sequence and metadata. Taking a polyglot approach involving multiple languages, libraries, and persistence mechanisms, sequence data can be aggregated from publicly available and local repositories. Data are exposed in the form of a RESTful web service, formatted for easy querying, and retrieved for downstream analyses. As a proof of concept, we have developed a resource for annotated HIV-1 …

Mrub_2642, Mrub_1054, And Mrub_1059 Genes Are Orthologs Of The Escherichia Coli Genes B2942, B0159, And B2687 Genes, Respectively, Which Code For Methionine Adenosyltransferase, Adenosylhomocysteine Nucleosidase, And S-Ribosylhomocysteine Lyase, Nicholas M. Orslini, Dr. Lori R. Scott

Meiothermus ruber Genome Analysis Project

This project is part of the Meiothermus ruber genome analysis project, which uses the bioinformatics tools associated with the Guiding Education through Novel Investigation –Annotation Collaboration Toolkit (GENI-ACT) to predict gene function. We investigated the biological function of the genes Mrub_2642, Mrub_1054, and Mrub_1059.

We predict that Mrub_2642 encodes the enzyme methionine adenosyltransferase (DNA coordinates [2677251…2678426] on the reverse strand), the first step of the methionine degradation pathway (KEGG map number 00270). Methionine adenosyltransferase catalyzes the conversion of the substrates, ATP, L-methionine, and water, to yield the products S-adenosyl-L-methionine (SAM), inorganic phosphate, and diphosphate. Mrub_1054 encodes adenosylhomocysteine nucleosidase (DNA …

Mrub_1867, Mrub_1868, And Mrub_1869 Genes Are Predicted Orthologs Of The B2279, B2280, And B2281 Genes Found In Escherichia Coli Coding For The Nadh Dehydrogenase Subunits K, J, And I Respectively, Wade Smith, Dr. Lori R. Scott

Meiothermus ruber Genome Analysis Project

This project is part of the Meiothermus ruber genome analysis project, which uses the bioinformatics tools associated with the Guiding Education through Novel Investigation –Annotation Collaboration Toolkit (GENI-ACT) to predict gene function. We investigated the biological function of the genes Mrub_1867, Mrub_1868, and Mrub_1869. We predict that Mrub_1867 (DNA coordinates 1927237..1927527 on the reverse strand), Mrub_1868 (DNA coordinates 1927524..1928123 on the reverse strand), and Mrub_1869 (DNA coordinates 1928248..1928781 on the reverse strand) are subunits of the NADH: ubiquinone oxidoreductase complex (KEGG map number 00190). This complex catalyzes the translocation of H+ across the cytoplasmic …

A Phylogenetic And Environmental Analysis Of Brazilian Placosoma Lizards, Kai A. Farje-Van Vlack

Dissertations and Theses

Placosoma is a genus comprised of the Brazilian spectacled lizards P. champsonotus, P. cipoense, P. cordylinum, P. glabellum, and P. limaverdorum. While P. champsonotus, P. cordylinum, and P. glabellum occupy the southern coast of Brazil, P. cipoense is found in the montane grasslands north of that range, and P. limaverdorum was recently discovered in forest isolates that persist within the semi-arid Caatinga. This study elucidates the ecological and evolutionary relationships among these morphologically similar lizards. Using mitochondrial and nuclear gene sequences, genus-wide phylogenies were inferred through Bayesian inference and a species tree approach, …

Mitochondrial And Nuclear Patterns Of Conflict And Concordance At The Gene, Genome, And Behavioral Scales In Desmognathus Salamanders, Justin D. Kratovil

Theses and Dissertations--Biology

Advancements in molecular sequencing have revealed unexpected cryptic genetic diversity and contrasting evolutionary histories within genes and between genomes of many organisms; often in disagreement with recognized taxonomy. Incongruent patterns between the mitochondrial and nuclear evolutionary history can have several plausible explanations, but widespread systematic conflict inevitably challenges our conceptions of species boundaries when there is discordance between coevolving and coinherited genomes. It is unknown to what degree mitonuclear conflict drives the process of divergence, or how ubiquitous these patterns are across the tree of life. To understand the evolutionary relevance of intergenomic discordance we must identify the conflicting patterns …