Gene Expression Evolution Following Hybridization and Genome Duplication in Cotton (genus Gossypium)

Polyploidy, or whole genome duplication, is a common feature among plants, occurring in possibly more than half of all angiosperm species. Decades of research has revealed that polyploidy can have profound impacts on phenotypic, genomic, and epigenetic traits. Some changes associated with polyploidy arise immediately from the genomic shock caused by duplicating and combining genomes, while other changes result from long-term evolutionary processes that operate on duplicated and redundant genes and genomes. Within this context, this dissertation specifically explores allopolyploidy (polyploidy involving divergent genomes) and its effects on members of the cotton genus (Gossypium). The work in this dissertation focuses on gene expression evolution, utilizing natural and synthetic Gossypium allopolyploids and a F1 hybrid to characterize the expression changes contributed by various stages of the allopolyploidization process. From these efforts, we find significant levels of expression evolution among the Gossypium species, which all include a maternal A-genome and a paternal D-genome . In the course of this research we have revealed several surprising results, for example that genes from the D-genome of the F1 hybrid and allopolyploids are more often over-expressed relative to the A-genome, when they are compared to the ancestral condition, meaning that genomic merger and allopolyplody in Gossypium has the net effect of creating D-genome expression biases. Furthermore, for some genes we find cases where this expression bias has gone to completion, leading to total silencing of expression from one of copies of the merged genomes. We also show evidence that cisy-regulatory changes are a primary contributor to expression differences between the A and D Gossypium genomes. Finally, by analyzing linked genes along two genomic locations we find that proximity can play a role in constraining expression evolution, though we also show that this proximity effect is not universally true. Beyond these unexpected findings, we also capitalized on the well-understood phylogenetic framework of the Gossypium species to place expression evolution in a temporal context. We find that there are immediate effects associated with the genome merger, and that these effects may explain approximately one-quarter of the expression biases found among the natural allotetraploid species, or to put it another way, one-quarter of the expression alterations found in the 1-2 million year old allotetraploids happened immediately upon their formations. Furthermore, among all five natural allotetraploids, we find that expression biases tend to become more extreme, indicating that when maintained in duplicate, the expression profiles of Gossypium genes tend to diverge. Finally, between the five diversified natural Gossypium allotetraploids we find the most extreme expression evolution in G. tomentosum, a wild species endemic to the Hawaiian Islands, followed by G. barbadense and G. hirsutum, the two allotetraploids cottons domesticated for fiber production. These results indicate that natural histories may contribute to expression biases, including domestication and island colonization

Examining the effectiveness of ecotourism as a funding source for protected area management in Guyana

Protected areas in tropical rainforests serve many important ecosystem services, including carbon sequestration. These areas are often in need of donor or grant funding to operate as governments in tropical forested countries are not always able to provide adequate funds for protection. This paper focuses on the Iwokrama International Center for Rainforest Conservation and Development in the South American country of Guyana, which has had funding issues since the global economic crisis of 2008 and an accompanying shift in donor country financial priorities. Increasing the amount of sustainable ecotourism in the Iwokrama reserve was identified as a potential source for earning enough revenue to offset external funding losses. Current Iwokrama tourism capacity was evaluated and a formula was created to determine the highest possible amount of ecotourism revenue based on sustaining maximum capacity over the course of a calendar year. Findings indicated that sustainable tourism has the potential to contribute US$853,940 in funding if 1,464 guests could be sustained for an entire year (25$598,250 from the 2013 tourism revenue of US$255,690 brought in by 605 tourists (10.33% of full capacity). The increased revenue would be very useful in making up for the 40% drop in grants and donor funding between 2012 and 2013 which caused severe austerity measures to be implemented and nearly resulted in termination of operations. Recommendations for attaining this level of ecotourism were made pertaining to marketing and partnerships with international organizations

As Hot as the Sun: Aztec Fevers, Medicine, and Magic in 16th-Century Mexico

Fevers had a significant presence in Mexico's sixteenth-century medical manuscripts, a consequence of the endemic and epidemic infections common to the pre and post-Hispanic eras. The distinctly Aztec conceptualization of these fevers invites further inquiry into the Aztec medical system. The Aztecs recognized multiple types of fevers, both natural and supernatural, manifesting in hot and cold forms. Thus, fevers can serve as a lens through which to examine the Aztecs' perception of the body and the universe, as well as the cosmic structure, dualities, and deities that governed the two. Furthermore, the animistic entities that connected the body to the divine also played a role in the development of fever. To address this state of disequilibrium, health practitioners relied upon their knowledge of the body, disease symptomology, and their vast pharmacopeia. In cases where a condition was suspected of having a supernatural etiology, these practitioners turned to magic

U.S. immigration law: children as a unifying means to immigration reform

This thesis seeks to evaluate U.S. immigration law and policy in light of their observable impact on children. My purpose is to review and assess the efficacy of current family reunification law specifically as regards minors: its clarity or ambiguity, consistency in application, and its effects on respect for the rule of law and just consequences. Section one addresses normative dimensions of justice including the legal notion that a punishment meted out should be proportionate to the crime of the perpetrator, the idea of consistency as a necessary though insufficient aspect of justice, and the importance of understanding the complexities of the casually used notion of the “rule of law.” Section two considers the legal and social precedents for special consideration of minors through a historical review comparing the development of immigration law and the concept of “childhood.” Section three details specific failures under immigration law for children with a special focus on the additional grounds of inadmissibility outlined in the Illegal Immigration Reform and Responsibilities Act (IIRAIRA). My goal is to expose the consequences such laws have on minors as well as the ways significant inconsistencies undermine the immigrant, adjudicator, and nation’s respect for the law. My analysis will conclude with recommendations for reform in light of the plenary power doctrine and the notion that minors without legal status may not expect protection under our laws. Perhaps if advocates for reform on either side of the debate began with reform for children, concessions could be made leading to more coherent and comprehensive policies for our nation

The Faulty Law and Economics of the “Baseball Rule”

This Article examines the so-called “Baseball Rule,” the legal doctrine generally immunizing professional baseball teams from liability when spectators are hit by errant balls or bats leaving the field of play. Following a recent series of high-profile fan injuries at Major League Baseball (MLB) games, this century-old legal doctrine has come under increased scrutiny, with both academic and media commentators calling for its abolition. Nevertheless, despite these criticisms, courts have almost uniformly continued to apply the Baseball Rule to spectator-injury lawsuits. This Article offers two contributions to the ongoing debate surrounding the Baseball Rule. First, it provides new empirical evidence establishing that the risk of being hit by an errant ball or bat at a professional baseball game has increased considerably in recent years. Specifically, fans attending MLB games today are sitting more than 20 percent closer to the field than they were when the legal doctrine was first established. This fact, along with other changes in the way in which the game is played and presented to fans, have converged to substantially reduce the reaction time that spectators have to protect themselves from flying objects entering the stands, calling into question courts’ continued reliance on the century-old rule. Second, the Article makes the novel observation that courts and academic commentators have, to date, largely failed to reconsider the Baseball Rule in light of the emergence of the law-and-economics movement, and in particular the contributions the movement has offered regarding the optimal apportionment of tort liability. By subjecting the doctrine to such an economic analysis, this Article finds that the host team will usually constitute the lowest-cost or best risk avoider, thus suggesting that the legal immunity currently provided to teams by the Baseball Rule inefficiently allocates tort liability in spectator-injury lawsuits. As a result, the Article concludes by contending that future courts (or legislatures) should reject the Baseball Rule and instead hold professional baseball teams liable for spectator injuries. Specifically, it asserts that the Baseball Rule should be replaced by a strictliability regime, thereby better incentivizing teams to implement the most economically efficient level of fan protection in their stadiums

Duplicate gene expression in allopolyploid Gossypium reveals two temporally distinct phases of expression evolution

<p>Abstract</p> <p>Background</p> <p>Polyploidy has played a prominent role in shaping the genomic architecture of the angiosperms. Through allopolyploidization, several modern <it>Gossypium </it>(cotton) species contain two divergent, although largely redundant genomes. Owing to this redundancy, these genomes can play host to an array of evolutionary processes that act on duplicate genes.</p> <p>Results</p> <p>We compared homoeolog (genes duplicated by polyploidy) contributions to the transcriptome of a natural allopolyploid and a synthetic interspecific F₁hybrid, both derived from a merger between diploid species from the <it>Gossypium </it>A-genome and D-genome groups. Relative levels of A- and D-genome contributions to the petal transcriptome were determined for 1,383 gene pairs. This comparison permitted partitioning of homoeolog expression biases into those arising from genomic merger and those resulting from polyploidy. Within allopolyploid <it>Gossypium</it>, approximately 24% of the genes with biased (unequal contributions from the two homoeologous copies) expression patterns are inferred to have arisen as a consequence of genomic merger, indicating that a substantial fraction of homoeolog expression biases occur instantaneously with hybridization. The remaining 76% of biased homoeologs reflect long-term evolutionary forces, such as duplicate gene neofunctionalization and subfunctionalization. Finally, we observed a greater number of genes biased toward the paternal D-genome and that expression biases have tended to increases during allopolyploid evolution.</p> <p>Conclusion</p> <p>Our results indicate that allopolyploidization entails significant homoeolog expression modulation, both immediately as a consequence of genomic merger, and secondarily as a result of long-term evolutionary transformations in duplicate gene expression.</p

Cue-Reactors: Individual Differences in Cue-Induced Craving after Food or Smoking Abstinence

Background: Pavlovian conditioning plays a critical role in both drug addiction and binge eating. Recent animal research suggests that certain individuals are highly sensitive to conditioned cues, whether they signal food or drugs. Are certain humans also more reactive to both food and drug cues? Methods: We examined cue-induced craving for both cigarettes and food, in the same individuals (n = 15 adult smokers). Subjects viewed smoking-related or food-related images after abstaining from either smoking or eating. Results: Certain individuals reported strong cue-induced craving after both smoking and food cues. That is, subjects who reported strong cue-induced craving for cigarettes also rated stronger cue-induced food craving. Conclusions: In humans, like in nonhumans, there may be a ‘‘cue-reactive’ ’ phenotype, consisting of individuals who are highly sensitive to conditioned stimuli. This finding extends recent reports from nonhuman studies. Further understanding this subgroup of smokers may allow clinicians to individually tailor therapies for smoking cessation

The Paraventricular Thalamus as a Critical Node of Motivated Behavior via the Hypothalamic-Thalamic-Striatal Circuit

In this review, we highlight evidence that supports a role for the paraventricular nucleus of the thalamus (PVT) in motivated behavior. We include a neuroanatomical and neurochemical overview, outlining what is known of the cellular makeup of the region and its most prominent afferent and efferent connections. We discuss how these connections and distinctions across the anterior-posterior axis correspond to the perceived function of the PVT. We then focus on the hypothalamic-thalamic-striatal circuit and the neuroanatomical and functional placement of the PVT within this circuit. In this regard, the PVT is ideally positioned to integrate information regarding internal states and the external environment and translate it into motivated actions. Based on data that has emerged in recent years, including that from our laboratory, we posit that orexinergic (OX) innervation from the lateral hypothalamus (LH) to the PVT encodes the incentive motivational value of reward cues and thereby alters the signaling of the glutamatergic neurons projecting from the PVT to the shell of the nucleus accumbens (NAcSh). The PVT-NAcSh pathway then modulates dopamine activity and resultant cue-motivated behaviors. As we and others apply novel tools and approaches to studying the PVT we will continue to refine the anatomical, cellular, and functional definitions currently ascribed to this nucleus and further elucidate its role in motivated behaviors

Foucault y el concepto de ideología

El presente trabajo se propone analizar la desvinculación de Foucault del concepto de ideología, así como de la dupla estructura-superestructura. Este rechazo se puede encuadrar en el intento de analizar en profundidad las relaciones entre los ámbitos de poder y de saber en diferentes contextos históricos. Para ver cómo Foucault articula su propio pensamiento es útil revisar una de las críticas que Habermas le realiza. En los capítulos 9 y 10 del Discurso filosófico de la modernidad, Habermas se ocupa del importante rol que recibe el concepto de poder en la denominada etapa genealógica, más precisamente a partir de Vigilar y castigar, sosteniendo que en el giro dado por Foucault se produciría una reducción de la explicación de las relaciones comunicacionales al de una teoría del poder. Esto nos abre la pregunta de si la propuesta foucaltiana no recae en una dualidad entre poder y saber que podría asimilarse con la dualidad entre estructura y superestructura que pretendía rechazar.Facultad de Humanidades y Ciencias de la Educació