Life Sciences Commons^™

Past And Present Patterns Of Neutral And Adaptive Genetic Diversity In Wild Mandrills (Mandrillus Sphinx), Anna Weber

University of New Orleans Theses and Dissertations

Although primates have fascinated researchers and the public alike for generations, one species that has remained enigmatic is the mandrill (Mandrillus sphinx), a large Cercopithecine monkey endemic to Central Africa. Mandrills are currently in decline due to bushmeat hunting, urbanization, and habitat loss. Neutral and adaptive genetic diversity are important tools for understanding evolutionary history and future viability, since diversity influences a species’ ability to adapt to a changing environment. However, thus far, minimal genetic information has been available for wild mandrills. Because of the dense vegetation in their tropical forest habitat, studying wild mandrills has proven to …

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

University of 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 …

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 …

Having A High-Activity Catechol-O-Methyltransferase Allele Is Associated With Elevated Anxiety And Lower Salivary Dehydroepiandrosterone But Also Lower Alpha Amylase In Children With Chromosome 22q11.2 Deletion Syndrome., Jessie Beebe

University of New Orleans Theses and Dissertations

Chromosome 22q11.2 deletion syndrome (22q11.2DS) results from a hemizygous deletion located on the long arm of chromosome 22. The most common deletion sizes affect between 30 and 90 genes. Individuals with 22q11.2DS may develop serious developmental and psychiatric disorders. The phenotype is highly variable, however, and may be influenced by allelic variation of the retained copies of genes covered by the deletion. I set out to examine the effects of two genes, catechol-O-methyltransferase (COMT) and proline dehydrogenase (PRODH), in relation to anxiety in children and adolescents with 22q11.2DS. Individuals with the major COMT allele (higher activity) have significantly higher anxiety …

Structure And Evolution Of Lizard Immunity Genes, Trent Santonastaso

University of New Orleans Theses and Dissertations

One of the most important gene families to play a role in adaptive immunity is the major histocompatibility complex (MHC). MHC class II loci are considered to be the most variable loci in the vertebrate genome, and studies have shown that this variability can be maintained through complex co-evolutionary dynamics between host and parasite. Despite the rich body of research into the MHC, there is comparatively little understanding of its genomic architecture in reptiles. Similarly, loci associated with innate immunity have received little attention in reptiles compared to other vertebrates. In the first chapter, we investigated the structure and organization …

A Transcriptomic Exploration Of Hawaiian Drosophilid Development And Evolution, Madeline M. Chenevert

University of New Orleans Theses and Dissertations

One in four known species of fruit flies inhabit the Hawaiian Islands. From a small number of colonizing flies, a wide range of species evolved, some of which managed to reverse-colonize other continental environments. In order to explore the developmental pathways, which separate the Hawaiian Drosophila proper and the Scaptomyza group that contains reverse-colonized species, the transcriptomes of two better-known species in each group, Scaptomyza anomala and Drosophila grimshawi, were analyzed to find changes in gene expression between the two groups. This study describes a novel transcriptome for S. anomala studies as well as unusual changes in gene expression …

Effective Statistical Energy Function Based Protein Un/Structure Prediction, Avdesh Mishra

University of New Orleans Theses and Dissertations

Proteins are an important component of living organisms, composed of one or more polypeptide chains, each containing hundreds or even thousands of amino acids of 20 standard types. The structure of a protein from the sequence determines crucial functions of proteins such as initiating metabolic reactions, DNA replication, cell signaling, and transporting molecules. In the past, proteins were considered to always have a well-defined stable shape (structured proteins), however, it has recently been shown that there exist intrinsically disordered proteins (IDPs), which lack a fixed or ordered 3D structure, have dynamic characteristics and therefore, exist in multiple states. Based on …

Understanding The Impacts Of Current And Future Environmental Variation On Central African Amphibian Biodiversity, Courtney A. Miller

University of New Orleans Theses and Dissertations

Global climate change is projected to impact multiple levels of biodiversity by imposing strong selection pressures on existing populations, triggering shifts in species distributions, and reorganizing entire communities. The Lower Guineo-Congolian region in central Africa, a reservoir for amphibian diversity, is predicted to be severely affected by future climate change through rising temperatures and greater variability in rainfall. Geospatial modelling can be used to assess how environmental variation shapes patterns of biological variation – from the genomic to the community level – and use these associations to predict patterns of biological change across space and time. The overall goal of …

Machine Learning Based Protein Sequence To (Un)Structure Mapping And Interaction Prediction, Sumaiya Iqbal

University of New Orleans Theses and Dissertations

Proteins are the fundamental macromolecules within a cell that carry out most of the biological functions. The computational study of protein structure and its functions, using machine learning and data analytics, is elemental in advancing the life-science research due to the fast-growing biological data and the extensive complexities involved in their analyses towards discovering meaningful insights. Mapping of protein’s primary sequence is not only limited to its structure, we extend that to its disordered component known as Intrinsically Disordered Proteins or Regions in proteins (IDPs/IDRs), and hence the involved dynamics, which help us explain complex interaction within a cell that …

Role Of Ime4 And Pho92 Proteins In Pho5 Regulation, Krishna Shah

Senior Honors Theses

In the yeast Saccharomyces cerevisiae, m6A methylation regulates the stability and translation of mRNA. Ime4, which is highly active in meiotic cells, recognizes consensus methyl sites in pre-mRNA and adds methyl groups to a small fraction of adenosine residues, whereas Pho92 binds to such methylated sites and promotes subsequent degradation. PHO5 transcripts expression is upregulated when IME4 and PHO92 are deleted. In the PHO5 transcript, near the stop codon of the open reading frame (ORF), there is a potential consensus methyl site that is predicted to be methylated, based on its location and excellent match to the consensus methylation sequence …

A Study On The Regulation Of Amino Acids And Glucose Sensing Pathways In Saccharomyces Cerevisiae, Mengying Chiang

University of New Orleans Theses and Dissertations

Nutrient availability regulates eukaryotic cell growth. This study focuses on two signaling pathways, involved in sensing amino acids and carbon sources, which allow cells to respond appropriately to their presence. The first part of this study shows that Ssy1, a plasma membrane localized sensor in the Ssy1-Ptr3-Ssy5 (SPS) amino acid sensing pathway, can detect 19 common L-amino acids with different potencies and affinities based on the physiochemical structure of amino acids. Substituents around alpha carbon are critical for amino acid sensing by Ssy1. Furthermore, a high concentration of cysteine is toxic to cells. Inactivation of SPS signaling confers resistance to …

Occurrence And Genetic Diversity Of Lemon Sharks (Negaprion Brevirostris) At A Nursery Ground At The Chandeleur Islands, Louisiana., Jonathan F. Mckenzie

University of New Orleans Theses and Dissertations

Anecdotal evidence suggested that immature lemon sharks (Negaprion brevirostris) occur at the Chandeleur Islands in southeastern Louisiana. From May 2009 to August 2011, the Nekton Research Laboratory at the University of New Orleans regularly sampled habitats at the Chandeleur Islands to confirm the presence of immature individuals of this species. During these efforts, 147 immature lemon sharks (neonates, young-of-the-year, and juveniles) were collected. Each shark was PIT tagged and a tissue sample was taken for genetic analyses. Sizes ranged from 56 – 177 cm total length. Sharks showed a preference for sandy substrate and smaller individuals showed significant preference …

Adenosine Triphosphate (Atp) Is A Candidate Signaling Molecule In The Mitochondria-To-Nucleus Retrograde Response Pathway, Feng Zhang, Tammy Pracheil, Janet Thornton, Zhengchang Liu

Biological Sciences Faculty Publications

Intracellular communication from the mitochondria to the nucleus is achieved via the retrograde response. In budding yeast, the retrograde response, also known as the RTG pathway, is regulated positively by Rtg1, Rtg2, Rtg3 and Grr1 and negatively by Mks1, Lst8 and two 14-3-3 proteins, Bmh1/2. Activation of retrograde signaling leads to activation of Rtg1/3, two basic helix-loop-helix leucine zipper transcription factors. Rtg1/3 activation requires Rtg2, a cytoplasmic protein with an N-terminal adenosine triphosphate (ATP) binding domain belonging to the actin/Hsp70/sugar kinase superfamily. The critical regulatory step of the retrograde response is the interaction between Rtg2 and Mks1. Rtg2 binds to …

Mitochondrial Dna Instability In Cells Lacking Aconitase Correlates With Iron Citrate Toxicity, Muhammad A. Farooq, Tammy M. Pracheil, Zhejun Dong, Fei Xiao, Zhengchang Liu

Biological Sciences Faculty Publications

Aconitase, the second enzyme of the tricarboxylic acid cycle encoded by ACO1 in the budding yeast Saccharomyces cerevisiae, catalyzes the conversion of citrate to isocitrate. aco1 Delta results in mitochondrial DNA (mtDNA) instability. It has been proposed that Aco1 binds to mtDNA and mediates its maintenance. Here we propose an alternative mechanism to account for mtDNA loss in aco1 Delta mutant cells. We found that aco1 Delta activated the RTG pathway, resulting in increased expression of genes encoding citrate synthase. By deleting RTG1, RTG3, or genes encoding citrate synthase, mtDNA instability was prevented in aco1 Delta mutant …

Localization And Mutational Analysis Of The Nuclear And Aggregation-Prone Ime4 Protein In Saccharomyces Cerevisiae, Patricia M. Dehon

University of New Orleans Theses and Dissertations

In Saccharomyces cerevisiae, Ime4 is a protein that is induced during meiosis and has a primary role in regulating sporulation in starving diploids. One function of Ime4 is methylation of adenosine residues within mRNA transcripts. Recent studies have shown Ime4 to be induced in haploids during the mating response, although its role in mating has not been determined. In this report, I identify the subcellular localization of Ime4 during the mating response through treatment with alpha factor. A plasmid containing IME4-GFP under the control of the medium strength promoter CYC1 was created in order to express the protein in a …

Comparative Phylogeography Of Central African Duikers Using Non-Invasive Sampling Methods, Stephan Ntie

University of New Orleans Theses and Dissertations

The present study sets out to assess patterns of evolutionary diversification in central African duikers (subfamily Cephalophinae). The sampling strategy consisted of collecting geo-referenced duiker feces across 43 sites and seven countries. However, several challenges related to the use of non-invasive samples needed to be addressed prior to large scale DNA amplification. First, the best storage method for obtaining DNA from fecal samples needed to be established. Our study revealed that while silica is best for nuclear microsatellite analyses, RNAlater is the best storage medium for maximal mitochondrial amplification. Moreover, extracting DNA as early as possible always provided the …

Evolution Of Nuclear Integrations Of The Mitochondrial Genome In Great Apes And Their Potential As Molecular Markers, Ivan D. Soto-Calderon

University of New Orleans Theses and Dissertations

The mitochondrial control region (MCR) has played an important role as a population genetic marker in many taxa but sequencing of complete eukaryotic genomes has revealed that nuclear integrations of mitochondrial DNA (numts) are abundant and widespread across many taxa. If left undetected, numts can inflate mitochondrial diversity and mislead interpretation of phylogenetic relationships. Comparative analyses of complete genomes in humans, orangutans and chimpanzees, and preliminary studies in gorillas have revealed high numt prevalence in great apes, but rigorous comparative analyses across taxa have been lacking.

The present study aimed to systematically compare the evolutionary dynamics of MCR numts in …