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- All Subjects: History of AIDS
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Description
Speciation is the fundamental process that has generated the vast diversity of life on earth. The hallmark of speciation is the evolution of barriers to gene flow. These barriers may reduce gene flow either by keeping incipient species from hybridizing at all (pre-zygotic), or by reducing the fitness of hybrids (post-zygotic). To understand the genetic architecture of these barriers and how they evolve, I studied a genus of wasps that exhibits barriers to gene flow that act both pre- and post-zygotically. Nasonia is a genus of four species of parasitoid wasps that can be hybridized in the laboratory. When two of these species, N. vitripennis and N. giraulti are mated, their offspring suffer, depending on the generation and cross examined, up to 80% mortality during larval development due to incompatible genic interactions between their nuclear and mitochondrial genomes. These species also exhibit pre-zygotic isolation, meaning they are more likely to mate with their own species when given the choice. I examined these two species and their hybrids to determine the genetic and physiological bases of both speciation mechanisms and to understand the evolutionary forces leading to them. I present results that indicate that the oxidative phosphorylation (OXPHOS) pathway, an essential pathway that is responsible for mitochondrial energy generation, is impaired in hybrids of these two species. These results indicate that this impairment is due to the unique evolutionary dynamics of the combined nuclear and mitochondrial origin of this pathway. I also present results showing that, as larvae, these hybrids experience retarded growth linked to the previously observed mortality and I explore possible physiological mechanisms for this. Finally, I show that the pre-mating isolation is due to a change in a single pheromone component in N. vitripennis males, that this change is under simple genetic control, and that it evolved neutrally before being co-opted as a species recognition signal. These results are an important addition to our overall understanding of the mechanisms of speciation and showcase Nasonia as an emerging model for the study of the genetics of speciation.
ContributorsGibson, Joshua D (Author) / Gadau, Jürgen (Thesis advisor) / Harrison, Jon (Committee member) / Pratt, Stephen (Committee member) / Verrelli, Brian (Committee member) / Willis, Wayne (Committee member) / Arizona State University (Publisher)
Created2013
Description
Affecting over 34 million people worldwide, (0.5% of the world population) HIV/AIDS is a pandemic that is not receding its control anytime soon (Sidibe 2011). Thirty years since the chaotic emergence of fear and misunderstanding, our knowledge of the virus and its subsequent syndrome has grown exponentially, but how much of this information is really getting to the people that need it? In the corners of the Earth, where scientific knowledge rarely reaches, what can we do to stop the deadly spread of this virus? And what of the countries with a large amount of knowledge, but still a ravaging problem present in their countries? When this information is disseminated- sometimes a matter of ‘if’ in certain countries, it is primarily through unreliable sources, most of the countries examined through the media, which has a tendency to skew and misinterpret information-specially scientific. This is the information that enters the lives of people in several different countries, for example, the United States, France, China, Brazil, Uganda, and South Africa: Misunderstandings of how to protect themselves from the virus, and its effects on the body. These misunderstandings have led to millions of lives lost as myths such as showering to cure AIDS and that AIDS only infect the ‘sinners’ continue to surface throughout the globe. The Public Health threat is due to knowledge deficits, and incorrect perceived ‘knowledge’ and ‘awareness of the problem’. Here, in a six-country analysis of common misconceptions and the subsequent policies and prevalence rate, it has begun to be clear that the hardest hit areas are those with the most stigma, the most misguided policies, the most uninformed leadership, and because of this, the most mislead citizens. The biological misunderstandings of HIV/AIDS are at the root of the public health threat continuing to keep its hold in the modern world, 30 years after its documented outbreak.
ContributorsSwanson, Marissa (Author) / Verrelli, Brian (Thesis director) / Rosenberg, Michael (Committee member) / Tassone, Erica (Committee member) / Barrett, The Honors College (Contributor) / College of Liberal Arts and Sciences (Contributor)
Created2012-12