Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 35 for “"Evolution & development"”.
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Role of subfunctionalized MYB paralogs in the evolution of pigmentation patterning in Clarkia
… questions at the intersection of genetics, development, and evolution. But recent advances in genomic and gene editing technologies are finally allowing for the in-depth study of the intricate spatial patterning of pigmentation, for example zebra stripes, butterfly wings, and flower spots. …
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Control of gene expression by cell size
… in the genome, is a common cellular state in evolution, development and disease. Polyploidy enlarges cell size and alters gene expression, producing novel phenotypes and functions. Although many polyploid cell types have been discovered, it is not clear how polyploidy changes physiology. …
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Geographic variation of song within and between subspecies of the Mangrove Warbler (Setophaga petechia castaneiceps and S. p. rhizophorae)
Bird song characteristics are unique for each species, but songs are not identical among con-specific individuals and variations may occur at different geographic scales throughout a species distribution. Geographic song variation is common in many species, particularly in Passerines due to their …
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Evolutionary Consequences of Metabolic Competition and Cooperation in Microbial Communities
… species. Gaining a better understanding of the evolutionary process within such dense communities has important implications for both clarifying genomic variation observed in the present as well as predicting future changes in microbial communities of particular interest to human health and …
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The Maintenance of Genetic Variation by Environmental Selection
<p>Understanding forces creating or maintaining the vast amount of biodiversity has been a major task of biologists. Genetic variation plays a major role in the creation of biodiversity because in contrast to environmental influence, genetic variants can be inherited. For a species in natural …
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Microbial Genome Evolution Due to Multifaceted Symbiosis within the Tsetse Fly (Diptera: Glossinidae)
… of this research is to gain insight on genome evolution resulting from symbiosis, particularly by examining bacteria with varying levels of host dependency and times of establishment. The tsetse fly (Diptera: Glossinidae) serves as a relatively simple model system to investigate evolutionary …
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UNCOVERING THE EVOLUTION AND DEVELOPMENT OF A NOVEL ABDOMINAL APPENDAGE IN BLACK SCAVENGER FLIES (SEPSIDAE: DIPTERA)
I explore the evolution and development of a novelty in sepsid flies where males have recently evolved an elaborate brush-like appendage on the fourth abdominal segment that varies in shape and size across the family. A comparative analysis showed that male sepsids pay for more ornate 4th sternite …
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Morphology, phylogeny, and evolutionary development in the weevils (Insecta: Coleoptera: Curculionoidea)
… understanding of rostrum structure prior to developmental studies examining its formation, a comparative study also was conducted of rostrum structure throughout Curculionoidea through examination of semi-thin sections. The weevil rostrum, for example, is a key evolutionary innovation that …
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The Role of Polyploidy in Phenotypic and Genomic Evolution in the Shy Monkeyflower, <i>Mimulus sookensis<i>
<p>In an ever-changing world, evolution is an essential process that may allow organisms to adapt to their environment through natural selection. All evolutionary processes act through a single fundamental medium: genetic variation. Polyploidy, or whole genome duplication, is a major mechanism for …
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Measurements and analyses of transposable element activity inside living cells
… restructure genomes and play crucial roles in evolution, development, and genetic disease. However, characterization of their detailed in vivo dynamics has been limited by a lack of direct observational methods. Here, we present novel methods that quantify biophysical characteristics of TEs in …
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Understanding the evolution of the apical organ in the early branching metazoan, Nematostella vectensis
… and metamorphosis. This thesis explores the evolution, development, and function of the apical organ and wider apical domain in cnidarian larvae, with a particular focus on Nematostella vectensis. As an early-branching metazoan, N. vectensis is a unique model for studying evolution of the …
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Modeling the effects of site-specific amino-acid preferences on protein evolution.
An important goal in the study of protein evolution is understanding which genetic changes that fixed in nature were selected for and why. However, understanding the functional consequence of any given mutation is a challenge because the effects of amino-acid changes are highly idiosyncratic across …
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Fate plasticity and reprogramming in genetically distinct populations of Danio leucophores
… a fundamental goal at the intersection of developmental and evolutionary biology. The skin pigment cells of vertebrates, derived from embryonic neural crest, are a useful system for elucidating mechanisms of fate specification, pattern formation, and how particular phenotypes impact …
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Sex and Fear: Mathematical models of mate choice, parental care, and maladaptive anxiety
… it is clear that the capacity for anxiety is an evolutionary adaptation. This presents a puzzle: why has natural selection not protected us from such a common malfunctioning of an adaptation? Chapter 3 develops a model that shows how the basic information constraints inherent in the problem of …
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Integrating genomic, transcriptomic and developmental approaches to investigate coloniality and life cycle evolution in the Hydractiniidae (Hydrozoa: Cnidaria)
Integrative approaches to evolutionary biology yield rich data through which we can truly begin to understand the marvels of life. This dissertation integrates genomic, transcriptomic, and developmental approaches to understand the evolution of prominent life history characters of the cnidarian …
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Developmental Single-Cell RNA Sequencing in the Sea Urchin Species Lytechinus variegatus and Heliocidaris erythrogramma
… roles is not completely understood, and the evolution of that process is even more enigmatic. In sea urchin embryos, cell fate specification and differentiation of cell types occurs through gene regulatory networks, or circuits of nodes or genes that interact with and regulate each other’s …
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Insect Development and Evolution: Perspectives on Individual and Colony-Level Phenotypes
<p>This dissertation analyzes the develop and evolution of insect phenotypes, ranging from the level of individuals to colonies. The first four chapters focus on wing patterning in the bella moth Utetheisa ornatrix. I begin by quantifying the pattern variation in the species, then attempt to …
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Transcription of human-specific duplicate genes
… but absent from any other, including our closest evolutionary cousins. Our interest in these genes is twofold: First, gene duplication is a fundamental process by which evolutionary innovations at the organismal level arise; and second, we believe that variation in these new genes is an important …
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Historical Processes and Genetic Implications of Limb Reduction and Loss in an Island Skink Lineage
Evolutionary simplification, or loss of complex characters, is a major theme in studies of body form evolution. The apparently infrequent evolutionary reacquisition of complex characters has led to the assertion (Dollo's Law) that once lost, complex characters may be impossible to re-evolve, at …
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