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Full-Text Articles in Biology

The Impeccable Timing Of The Apple Maggot Fly, Rhagoletis Pomonella (Dipetera: Tephritidae), And Its Implications For Ecological Speciation, Monte Arthur Mattsson Nov 2015

The Impeccable Timing Of The Apple Maggot Fly, Rhagoletis Pomonella (Dipetera: Tephritidae), And Its Implications For Ecological Speciation, Monte Arthur Mattsson

Dissertations and Theses

Speciation is the process by which life diversifies into discrete forms, and understanding its underlying mechanisms remains a primary focus for biologists. Increasingly, empirical studies are helping explain the role of ecology in generating biodiversity. Adaptive radiations are often propelled by selective fitness tradeoffs experienced by individuals that invade new habitats, resulting in reproductive isolation from ancestral conspecifics and potentially cladogenesis. Host specialist insects are among the most speciose organisms known and serve as highly useful models for studying adaptive radiations. We are just beginning to understand the pace and degree with which these insects diversify. The apple maggot, Rhagoletis …


Developmental Mechanisms That Support Genome Stability And Embryonic Survival In Stress-Tolerant Embryos Of The Annual Killifish Austrofundulus Limnaeus, Josiah Tad Wagner Sep 2015

Developmental Mechanisms That Support Genome Stability And Embryonic Survival In Stress-Tolerant Embryos Of The Annual Killifish Austrofundulus Limnaeus, Josiah Tad Wagner

Dissertations and Theses

In order to complete their life cycles, vertebrates require oxygen and water. However, environments are not always forgiving when it comes to constantly providing these basic needs for vertebrate life. The annual killifish Austrofundulus limnaeus is possibly the most well described extremophile vertebrate and its embryos have been shown to tolerate extremes in oxygen, salinity, and water availability. This phenotype is likely a result of the annual killifish life history, which includes periods of temporary habitat desiccation and oxygen deprivation, and requires the production of stress-tolerant embryos that depress metabolism in a state of suspended animation, known as diapause. Over …


The Role Of Pyrococcus Furiosus Transcription Factor E In Transcription Iniitiation, Robyn Lynn Eustis Sep 2015

The Role Of Pyrococcus Furiosus Transcription Factor E In Transcription Iniitiation, Robyn Lynn Eustis

Dissertations and Theses

All sequenced archaeal genomes encode a general transcription factor, TFE, which is highly conserved and homologous to the alpha subunit of the eukaryotic transcription factor TFIIE. TFE functions to increase promoter opening efficiency during transcription initiation, although the mechanism for this is unclear. The N-terminus of TFE contains a common DNA binding motif, a winged helix. At the tip of this winged helix is a highly conserved region of aromatic amino acids that is close to DNA during initiation. TFE activation can compensate for mutations in another transcription factor, TFB2, which is homologous to TFIIB. P. furiosus encodes two paralogs …


Neurobiology Of Seasonal Life-History Transitions, Ashley Rae Lucas Sep 2015

Neurobiology Of Seasonal Life-History Transitions, Ashley Rae Lucas

Dissertations and Theses

Many animals exhibit seasonal changes in life-history stages, and these seasonal transitions are often accompanied by dramatic switches in behavior. While the neuroendocrine mechanisms that regulate such behavioral transitions are poorly understood, arginine vasotocin (AVT) and neuropeptide Y (NPY) are excellent candidates because they regulate reproductive and feeding behavior, respectively. In this study, I asked if seasonal changes in AVT and/or NPY are concomitant with spring migration away from the breeding grounds, as male and female red-sided garter snakes (Thamnophis sirtalis parietalis) are transitioning from reproductive to non-reproductive behavior during this time. To address this question, I collected …


Investigations Of Larval Pacific Lamprey Entosphenus Tridentatus Osmotic Stress Tolerance And Occurrence In A Tidally-Influenced Estuarine Stream, Gregory Shell Silver Jun 2015

Investigations Of Larval Pacific Lamprey Entosphenus Tridentatus Osmotic Stress Tolerance And Occurrence In A Tidally-Influenced Estuarine Stream, Gregory Shell Silver

Dissertations and Theses

Pacific lamprey is a culturally valuable species to indigenous people, and has significant ecological importance in freshwater and marine ecosystems. Over the past several decades, constrictions in range and reductions in Pacific lamprey abundance have been observed in Western North America, and may be indicators of range-wide declines. In the face of declining populations, the U.S. Fish and Wildlife Service has partnered with tribal, state, federal, and local entities to implement a regional Pacific lamprey conservation agreement aimed at reducing threats to Pacific lamprey and improving their habitats and population status. Research needs identified in the conservation agreement include assessing …


Phenotypic And Mutational Consequences Of Mitochondrial Etc Genetic Damage, Michael James Lue Mar 2015

Phenotypic And Mutational Consequences Of Mitochondrial Etc Genetic Damage, Michael James Lue

Dissertations and Theses

Genetic mutation is the ultimate source of new phenotypic variation in populations. The importance of mutation cannot be understated, and constitutes a significant evolutionary force. Although single mutations may have little to no impact on organismal performance or fitness, when multiplied across the total number of potential sites within the genome, mutation can have a large impact. Accurate measurement of the rates, molecular mechanisms, and distributions of effects of mutations are critical for many applications of evolutionary theory. Despite the importance of both deleterious and beneficial mutations, their genome-wide patterns and phenotypic consequences are poorly understood when considering the mitochondrial …