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Character Displacement In Burkholderia Biofilm Communities And The Effect Of Adaptive History On The Evolution Of Niche Breadth, Crystal Nicole Ellis

Doctoral Dissertations

Ecologists agree that biodiversity is essential for maintaining highly productive and stable ecosystems, yet the mechanisms that generate and preserve diversity are unknown in many habitats. Competition for shared resources may cause selection to favor niche specialization, which reduces competition and reinforces diversity. If the environment is significantly altered, the ecological history of the remaining colonizer may influence fitness and capacity for diversification in new environments. In many cases, specialists have limited adaptive potential due to trade-offs generated by niche-specific adaptation; however, generalists may be adaptable in many habitats, which would make them good pioneer species for colonization. We investigated …

Interactions Between Adaptive Mutations In The Environment And The Consequences For Adaptation In Escherichia Coli, Kenneth Mark Flynn

Master's Theses and Capstones

Phenotypic plasticity, epistasis or both are expected to influence the adaptive value of mutations and, by extension, how organisms adapt to new environments. We investigated interactions among five mutations that arose and fixed in a laboratory-evolved population of E. coli in a variety of different external environments. Overall, we found that positive pleiotropy tended to be positive rather than antagonistic and that epistatic interactions were common regardless of the external environment. The nature of the epistatic interactions depended strongly on the external environment and altered which adaptive paths were selectively accessible. Ultimately, achieving high fitness in a new environment was …

Analysis Of Arabidopsis Thaliana Protein Phosphatase 2a C Subunit Expression, Megan M. Thompson

Master's Theses and Capstones

Reversible protein phosphorylation is required for presumably most biological pathways. One of the major enzymes involved in eukaryotic dephosphorylation is Protein Phosphatase 2A (PP2A). PP2A is composed of three subunits: A (scaffolding), B (regulatory), and C (catalytic). Our lab is interested in determining the function of the five C subunits (C1, C2, C3, C4 and C5) in Arabidopsis thaliana. We have identified a Na+-induced altered root growth phenotype in c4 mutant plants. The goal of this project was to determine expression of the five C subunit genes throughout the life cycle of Arabidopsis with emphasis on correlating the location of …

Genes Differentially Expressed At 1 Day, 6 Weeks, And 6 Months Of Age In Aortas Of Spontaneously Atherosclerotic White Carneau Pigeons, Suzanne Lee Pearlman

Master's Theses and Capstones

Genetics is reported to be the primary causative factor for individuals diagnosed with atherosclerosis, in the absence of known risk factors. The development of atherosclerosis in White Carneau (WC) pigeons is of genetic origin, making it an excellent model to study genetic factors.

Representational Difference Analysis (RDA) was used to determine genes differentially upregulated between three ages, at the celiac bifurcation of the aorta in WC pigeons. Genes responsible for spontaneous initiation of atherosclerosis were hypothesized as being differentially expressed at 1 day, while those differentially expressed at 6 weeks and 6 months were related to progression.

Multiple candidate genes …