Genetics and Genomics Commons^™

Erecta Family Genes Regulate The Shoot Apical Meristem And Organ Formation, Daniel A. Degennaro

Doctoral Dissertations

Plants are sessile and must adjust their organ growth to their environments. A reservoir of stem cells in the shoot apical meristem (SAM) supplies cells for differentiation into organs. The SAM must balance organ production with stem cell maintenance. The ERECTA family (ERfs) encodes the leucine-rich repeat receptor-like kinases ERECTA (ER), ERECTA-LIKE 1 (ERL1), and ERL2. ERf signaling regulates organ initiation and stem cell maintenance. Results presented in this work include the following:

1) WUSCHEL (WUS) and CLAVATA3 (CLV3) make up a negative feedback loop to maintain SAM size. WUS and CLV3 expression localization is critical for …

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 …

Regulatory Non-Coding Rnas Modulate Transcriptional Activation During B Cell Development, Mary Attaway, Tzippora Chwat-Edelstein, Bao Q. Vuong

Publications and Research

B cells play a significant role in the adaptive immune response by secreting immunoglobulins that can recognize and neutralize foreign antigens. They develop from hematopoietic stem cells, which also give rise to other types of blood cells, such as monocytes, neutrophils, and T cells, wherein specific transcriptional programs define the commitment and subsequent development of these different cell lineages. A number of transcription factors, such as PU.1, E2A, Pax5, and FOXO1, drive B cell development. Mounting evidence demonstrates that non-coding RNAs, such as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), modulate the expression of these transcription factors directly by binding …

The Effects Of Ppal-1 In Arabidopsis Gamete Development, Amanda J White, Susana Perez-Martinez, Mark P. Running

The Cardinal Edge

Prenylation is a type of post-translational modification in which a 15- or 20-carbon lipid is added to the carboxyl (C) terminus of the protein. Arabidopsis thaliana contains the PROTEIN PRENYLTRANSFERASE ALPHA SUBUNIT-LIKE (PPAL) gene, which encodes a protein with homology to the α-subunits of the three known prenylation enzymes, PFT, PGGT, and Rab-GGT. We previously identified two mutations in PPAL, one of which is ppal-1, which contains a T-DNA insertion in the fourth intron. We have previously observed that self-fertilizing heterozygous ppal-1 plants produce progeny in which homozygous ppal-1 is underrepresented. This project attempts to ascertain …

Investigation Of Notch Signaling In Cone Fate Specification In Vertebrate Retina, Xueqing Chen

Dissertations, Theses, and Capstone Projects

In the vertebrate retina, cone photoreceptors are crucial for high acuity color vision. Several retinal diseases lead to loss of cones and there is a need to identify the normal developmental genesis of these cells to inform the development of stem cell-based therapies. Cone genesis has previously been shown to be repressed by Notch signaling, however, the mechanism by which Notch signaling controls cone fate determination is still unclear. It has been identified that cone photoreceptors are formed from multipotent retinal progenitor cells (RPCs) that first generate genetically-defined, restricted RPCs with limited mitotic and fate potential to preferentially form cones …

Vitamin D Modulates Rett Syndrome Phenotypes And Underlying Cellular Pathways In An Mecp2-Mutant Mouse Model, Mayara De Cassia Ribeiro

Dissertations - ALL

Rett syndrome (RTT) is a progressive and severe X-linked neurodevelopmental disorder caused by mutations in the transcriptional regulator MECP2. There is currently no effective treatment for RTT. Female RTT patients develop relatively normally during the first 6-18 months of life, after which they undergo a period of rapid regression, losing the ability to talk, walk and purposefully use their hands, in addition to suffering from deceleration of head growth, and onset of repetitive, autistic behaviors. RTT symptoms can be partially reversed by the re-expression of Mecp2 in adult mice, suggesting the potential for post-symptomatic therapeutic intervention. Among the many dysfunctions …

Exploring Β-Cell Function And Heterogeneity In Obese Sm/J Mice, Mario Alejandro Miranda

Arts & Sciences Electronic Theses and Dissertations

Pancreatic β-cells perform glucose-stimulated insulin secretion, a process required to maintain systemic glucose homeostasis. Obesity promotes glycemic and inflammatory stress, causing β-cell death and dysfunction, resulting in diabetes. Efforts to improve β-cell function in obesity have been hampered by observations that β-cells are highly heterogeneous, varying in morphology, function, and gene expression. There is great need to understand the breadth of β-cell heterogeneity in health and obesity to improve diabetic therapies.High fat-fed SM/J mice spontaneously transition from hyperglycemic-obese to normoglycemic-obese with age, providing a unique opportunity to study β-cell adaptation. Here, we show that as they resolve hyperglycemia, obese SM/J …

Evolution And Development Of The Seed Coat In Gymnosperms, Cecilia Zumajo

Dissertations, Theses, and Capstone Projects

Gymnosperms and angiosperms are the most abundant plant lineages on earth and constitute a turning point in the evolution of plants because they are at the origin of the seed, a key morphological and developmental novelty in the evolution of land plant. Although the morphological variation of the seed, across seed plants, may on its own, explain the complexity of this structure, the origin, and evolution are even more, the understanding of these topics is still under discussion. Evidence shows that previous studies have often lacked the component of gene expression, particularly in species that are not model species. The …

Molecular Mechanisms Underlying Cell Fate Choice Within Specific Retinal Lineages, Estie Schick

Dissertations, Theses, and Capstone Projects

During development, retinal progenitor cells (RPCs) divide to form all of the cell types that make up the retina. Multipotent RPCs are competent to generate all retinal cell types, while restricted RPCs form specific lineages of cells. In particular, one genetically-defined RPC type preferentially gives rise to cone photoreceptors and horizontal cells. Many of the mechanisms that are responsible for directing cell fate choice within this lineage are unknown. This thesis largely focuses on examining the development of specific cell types and subtypes from restricted RPCs and on investigating the gene regulatory events that underlie cone photoreceptor and horizontal cell …

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 …

Creating A Protein Chimera To Study Regulation Of Muscle Diversity, Shannon Scarboro

Symposium of Student Scholars

Creating a protein chimera to study regulation of muscle diversity.

Body muscles are made of many individual super-cells, called muscle fibers, that have distinct properties and determine every individual’s strength and endurance. Initially all muscle fibers have identical characteristics, but become differentiated into specific types in adults. The mechanism of such transition is not well understood, despite its obvious importance for shaping human physicality.

Remarkable conservation of the muscle tissue enables us to use fruit flies to study the mechanisms of muscle fiber diversity. We hypothesized that the transcription factor Mef2 acts as a molecular switch that activates structural genes …

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 …

Transcriptional Control Of Dendritic Cell Function And Development, David Alexander Anderson Iii

Arts & Sciences Electronic Theses and Dissertations

Dendritic cells (DCs) are innate immune cells of the myeloid lineage that are specialized at pathogen recognition, cytokine production, and antigen presentation. Their functions and developmental pathways are largely conserved between mice and humans and mice. The DC lineage is composed of two major subsets, known as plasmacytoid DCs (pDCs) and classical DCs (cDCs). Research conducted to date suggests that the function of pDCs, limited to viral antigen recognition and type I interferon production, can be compensated by other immune cell lineages. On the other hand, there is a consensus that diversified subsets cDCs in mice and humans are essential …

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 …

Regulation Of Genome Architecture By Chromatin Remodeling In The Brain, Jared Vega Goodman

Arts & Sciences Electronic Theses and Dissertations

Brain development requires exquisite control of gene expression to establish and refine the proper circuitry of the nervous system. Gene expression control is under the purview of several cellular processes, including chromatin regulation in the form of DNA modification, histone modification, and nucleosome remodeling. Chromatin remodeling enzymes are the major effectors of nucleosome remodeling. These enzymes are clearly involved in brain development – mutations in chromatin remodeling enzymes are likely causative for neurodevelopmental disorders of cognition. Chromatin remodeling enzymes have discrete molecular functions and binding profiles and similarly control distinct phases of nervous system maturation. Chd4 is a Chd family …

The Effects Of Mapk Signaling On The Development Of Cerebellar Granule Cells, Kerry Morgan

University Scholar Projects

The granule cells are the most abundant neuronal type in the human brain. Rapid proliferation of granule cell progenitors results in dramatic expansion and folding of the cerebellar cortex during postnatal development. Mis-regulation of this proliferation process causes medulloblastoma, the most prevalent childhood brain tumor. In the developing cerebellum, granule cells are derived from Atoh1-expressing cells, which arise from the upper rhombic lip (the interface between the roof plate and neuroepithelium). In addition to granule cells, the Atoh1 lineage also gives rise to different types of neurons including cerebellar nuclei neurons. In the current study, I have investigated the …

The Effects Of Mapk Signaling On The Development Of Cerebellar Granule Cells, Kerry Morgan

Honors Scholar Theses

The granule cells are the most abundant neuronal type in the human brain. Rapid proliferation of granule cell progenitors results in dramatic expansion and folding of the cerebellar cortex during postnatal development. Mis-regulation of this proliferation process causes medulloblastoma, the most prevalent childhood brain tumor. In the developing cerebellum, granule cells are derived from Atoh1-expressing cells, which arise from the upper rhombic lip (the interface between the roof plate and neuroepithelium). In addition to granule cells, the Atoh1 lineage also gives rise to different types of neurons including cerebellar nuclei neurons. In the current study, I have investigated the …

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 …

Translational Fidelity And Its Role In Neuronal Homeostasis, Markus Terrey

Electronic Theses and Dissertations

The process of translation, which refers to decoding genetic information from mRNA to protein, is vital for all cellular function. Translational fidelity starts at the level of aminoacylation of transfer RNAs (tRNA). This reaction is catalyzed by aminoacyl tRNA synthetases where each amino acid is transferred to its corresponding cognate tRNA. Because tRNAs harbor the anticodon sequence to decodes a particular mRNA codon, the specific aminoacylation of the tRNA with a cognate amino acid establishes the rules of decoding genetic code into proteins. Aminoacylated tRNAs are then delivered to ribosomes, where ribosomes in a highly organized manner need to accurately …

Genetic Pathway Analysis Of Abnormal Facial Development In Nonsyndromic Cleft Lip And Palate, Lorena Maili

Dissertations & Theses (Open Access)

Nonsyndromic cleft lip with or without cleft palate (NSCLP) is the most common craniofacial birth defect resulting from incomplete fusion of the facial prominences during development, which leaves a gap in the lip, primary palate and/or the secondary palate. NSCLP affects 135,000 NSCLP newborns worldwide each year based on a birth prevalence of 1 per 700 live births. While surgical treatments have dramatically improved, many long-term health issues persist, imposing significant medical, psychosocial and economic burdens. Familial aggregation and segregation analyses suggest genetic contributions underlie NSCLP, but despite decades of study, only a small portion of the NSCLP genetic liability …

Zebrafish (Danio Rerio) Hoxb6: An Exploration Into The Divergence Of Genomic Dna Sequence And Gene Expression Across Teleost Fishes Post-Genome Duplication, Amber Lynn Rittgers, Pierre Le Pabic, Adam Davis

Georgia Journal of Science

Hoxb6 is an evolutionarily conserved developmental regulatory gene that functions, in part, to pattern several organs and organ systems within the embryonic trunk during vertebrate embryogenesis. The cis-regulatory circuitry mediating trunk expression in mouse (Mus musculus) may be conserved across gnathostome vertebrates, as several other species show similar trunk expression patterns, including chicken (Gallus gallus), dogfish shark (Scyliorhinus canicula), and several teleost fishes. A whole genome duplication event that occurred in the lineage leading to teleost fishes has generated at least two Hoxb6 genes, hoxb6a and b6b. Two teleost fishes of the …

The Influence Of Autism Linked Gene Topoisomerase 3b (Top3b) On Neural Development In Zebrafish, Sydney Doolittle

Honors College Theses

Autism Spectrum Disorder is a class of developmental disabilities characterized by a spectrum of social, communication, and behavioral impairments in affected individuals. Studies have shown these defects stem from abnormal brain development during critical periods during early development. The underlying genetic cause of these impairments is not well understood but is believed to be a combination of a complex pairing of genetic and environmental factors. One of the genetic factors that has been recognized to influence the phenotypic symptoms of ASD is the enzyme topoisomerase 3β (top3β.) Topoisomerases are responsible for the prevention of supercoiling during DNA replication. Top3β is …

Transactivation And Mitochondrial Activity Are Affected By High Temperature In C. Elegans Sperm, Jacqueline Mcvay

Scripps Senior Theses

Sexual reproduction has a conserved flaw in that it is temperature sensitive. Exposure to high temperature leads to male infertility, but little is known about the underlying mechanism. Understanding these mechanisms is important for agriculture and reproductive medicine. Using C. elegans, we investigated two potential aspects of male fertility that may be affected by high temperature conditions: activation of sperm by seminal fluid and sperm mitochondrial activity. There are two pathways for sperm activation in C. elegans: the SPE-8 pathway in hermaphrodites and the TRY-5 pathway in male seminal fluid. Hermaphrodite sperm with a mutation in spe-8 can …

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 …

The Origin Of Novel Trait Inferred From Transcriptomic Analysis And A Targeted Gene Approach In The Beetle Horns., Naureen Fatima

Graduate Theses, Dissertations, and Problem Reports

The origin of the evolutionary new trait (evolutionary novelty) and its subsequent evolution is of great interest for biologists in various fields, and beetle horns have been used to address this fundamental biological question. Previous studies on one of the horned beetle species, Onthophagus taurus, that utilized comparative gene expression analyses, suggested legs to be a strong candidate of the origin of horns. At the same time, their horns are secondary sexual traits whose development is regulated by the same gene (doublesex) as genitalia, which also originates from paired appendages such as legs. However, little is known …

Periocular Mesenchyme Heterogeneity During Morphogenesis Of The Vertebrate Ocular Anterior Segment, Kristyn L. Van Der Meulen

Theses and Dissertations--Biology

The vertebrate eye is a complex organ, responsible for the primary sense with which we interact with our environment: vision. Development of the eye is a tightly regulated process, controlled by a vast network of genes. This process begins with eye morphogenesis, when the eye structure is formed through a series of morphogenetic movements and culminates in the creation of the optic cup, lens, and presumptive optic stalk. Next, retinal differentiation creates the critical cell layers of the retina needed to process light waves that enter the eye, including rod and cone photoreceptors, interneurons, and support cells. Failure in either …

Leveraging Transcriptomic Approaches To Identify Differences In Genetic Programming Driving Two Distinct Wound Healing Mechanisms, Regeneration And Fibrosis, In Acomys And Mus, Shishir K. Biswas

Theses and Dissertations--Biology

Why can some animals and others cannot? This fundamental question has fueled scientists studying regeneration for hundreds of years since early observations in crayfish, salamanders and many other organisms. While most contemporary work in regeneration is done in a handful of species including salamanders, zebrafish and flatforms, these organisms lack a closely-related, non-regenerating sister species from which unique genetic differences can be identified. Additionally, while much has been learned from these organisms, they do not share fundamental biological traits with mammals (endothermy, metabolism and immune system) which limits the ability to translate this research for clinical medicine. To this end, …

Molecular Mechanisms Regulating Optic Fissure Fusion During Zebrafish Eye Development, Megan Weaver

Theses and Dissertations--Biology

Vertebrate retinal development requires timely and precise fusion of the optic fissure. Failure of this event leads to congenital vision impairment in the form of coloboma. Recent studies have suggested hyaloid vasculature to be involved in OF fusion. In order to examine this link, we analyzed optic fissure fusion and hyaloid vasculogenesis in the zebrafish pax2a noi mutant line. We first determined that pax2a^-/- embryos fail to accumulate F-actin in the optic fissure prior to basement membrane (BM) degradation. Furthermore, using 3D and live imaging we observed reduced OF hyaloid vascularization in pax2a^-/- embryos. When examining the connection …