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 169 for “"natural populations"”.
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Microevolutionary processes in natural populations of the waterstrider Aquarius remigis
… sexes, and sexual size dimorphism (SSD) provides natural experiments in the evolution of traits constrained by genetic correlations. In this thesis I relate sex-specific fitness functions, opportunity for selection, and genetic correlations among body size components to the adaptive significance …
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Heritable Variation in Natural Populations of Populus Deltoides (Bartr.) in Illinois
Made available in DSpace on 2014-12-04T20:17:18Z (GMT). No. of bitstreams: 1 6402904.pdf: 5130563 bytes, checksum: 347d70b257b4cee85b97e2c7d046110e (MD5) Previous issue date: 1963
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Examining patterns of CRISPR immunity in natural populations of Sulfolobus islandicus
… are important for shaping microbial diversity in natural environments. Viruses impact their hosts through predation and also through gene flow. The recently discovered microbial CRISPR immune system is a mechanism that modulates interactions between hosts and viruses, and in the process, records a …
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Emergent patterns of diversity and dynamics in natural populations of planktonic Vibrio bacteria
… in the distribution and abundance of Vibrio populations and that groups of organisms with >98-99% 16S rRNA sequence similarity maintain similar responses to temperature-mediated environmental change. Fine-scale analysis of the genetic structure within one Vibrio population (>99% rRNA …
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Using molecular genetic techniques to detect outcrossing in natural populations of a self-fertilizing fish
… self-fertilization; this process results in populations of homozygous clones. Most natural populations consist entirely of hermaphrodites, but phenotypically distinct, fertile males occur at frequencies up to 24% on some islands off the coast of Belize. The presence of large numbers of males …
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Lethal and Semilethal Mutation Frequency of the First and Second Chromosomes in Two Natural Populations of "Drosophila melanogaster"
… by the lethal gene frequencies between two natural populations of "Drosophila melanogaster". High levels of trichloroethylene (TCE) and other suspected mutagens and carcinogens, i.e., vinyl chloride, chloroform, etc., have reportedly been found in subsurface soil and waters near downtown Des …
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Development of approaches for investigating the distribution of toxoplasma gondii infection in natural populations of animals and humans
… about the detailed distribution in localised natural populations. In this study we investigated host genotype and spatial location in relation to T. gondii infection and genotypes. We collected wood mice (Apodemus sylvaticus) from 4 sampling sites within a localised peri-aquatic woodland …
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Investigation of genetic and epigenetic mechanisms of iNOS gene expression in infection of natural populations of Apodemus sylvaticus with the parasite Toxoplasma gondii
… few that have studied mechanisms of infection in natural populations. Laboratory studies have shown that the host gene iNOS influences sensitivity and resistance to T. gondii infection. This study sets out to investigate the role of genetic and epigenetic mechanisms of iNOS gene expression in the …
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The characterization of MHC Class II genes of the Nile crocodile (Crocodylus niloticus) : an investigation of mechanisms that shape genetic diversity in natural populations
… amino acid diversity in the PBR, such that natural selection will favour PBR diversity in natural populations. This study investigated mechanisms that shape genetic diversity of MHC class II genes in a natural population of the Nile crocodile, Crocodylus niloticus. Using …
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Patterns, maintenance and the evolution of behavioral variation and covariance: the presence of personalities in kangaroo rats
… the maintenance of variation within and between natural populations of D. merriami and investigated the mechanisms that may lead to the evolution of behavioral syndromes or "personalities". I used a structural equation modeling and information-theoretic approach to demonstrate that D. merriami …
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ECOLOGY AND GENECOLOGY OF FUCUS DISTICHUS (L) POWELL
… F. distichus ssp. evanescens were evaluated in natural populations in New England. Both subspecies exhibited maximum growth during early summer, a slight decline in late summer, and a brief resurgence in the early fall. The maximum growth rates (in terms of elongation) for ssp. edentatus and …
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Studies on Selection in Natural and Experimental Populations of Drosophila Pseudoobscura
… Body size was studied in six experimental populations of Drosophila pseudoobscura which had been exposed to different temperatures. These populations were genetically identical at their inception but were maintained thereafter at different temperatures. After six years a striking genetic …
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A Test of Rad Capture Sequencing on Ethanol-Preserved Centennial and Contemporary Specimens of Philippine Fishes
… ecological characteristics and genetic change in natural populations in different time scales can reveal how anthropogenic stressors affect natural populations and can improve the success of conservation strategies. The purpose of the Philippines Partnerships for International Research and …
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Characterizing Deleterious Genomic Mutations in The Presence of Overdominance (a Computer Simulation Approach)
… that the standing genetic variation in natural populations is solely due to mutation-selection (M-S) balance. According to this assumption, overdominance does not contribute to heterosis and standing genetic variation. The extent to which this assumption is valid is unknown. In this …
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Comparative Phylogeography of Eastern Chipmunks and White -Footed Mice: Population Histories Since the Last Glacial Maximum
… in disrupting evolutionary processes within natural populations.
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Development of prairie cordgrass (spartina pectinata link) as a dedicated bioenergy crop
… To further investigate its genetic resources, natural prairie cordgrass populations collected from the Midwest to east coast of U.S. were planted and evaluated in an experimental nursery at Urbana, IL. The 4-year field study of 42 prairie cordgrass natural populations revealed extensive …
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Viral diversity and host-virus interactions in the model crenarchaeon Sulfolobus islandicus
… evolutionary forces and key players shaping natural populations. Our understanding of viral impact on host physiology however, is based on a few model systems that represent a small fraction of the life-history strategies employed by hosts or viruses across the three domains of life. The …
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Metabolic differentiation in the lichen Cladonia portentosa from different wet nitrogen deposition regimes’
… a C18:2 ester showed the opposite trend in natural populations of C. portentosa. Results obtained for C. portentosa collected from the N manipulation site Whim Moss indicated that ammonium is causal for the increase of two of the identified betaine lipids in natural populations in C. …
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DNA diversity in prairie cordgrass (Spartina pectinata Link) populations indigenous to the United States
… genetic diversity found within and among native populations. Chloroplast DNA and nuclear DNA analysis provides a basic understanding into the amount of genetic variation present in this species. In this study, two highly polymorphic chloroplast regions were sequenced across 16 natural …
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