Thesis (Ph. D.)--University of Michigan, 1928. / Thesis note on label mounted on t.p. "Papers from the Department of Botany of the University of Michigan, no. 298. Walker prize essay of the Boston Society of Natural History, 1928." "Reprinted ... from the Botanical gazette, vol. LXXXVII, no. 2, March 1929." "Literature cited": p. 252-257.

Presented as thesis (Ph. D.)--University of Wisconsin--Madison, 1930. / Cover title. Reprinted from American journal of botany, vol. XVIII, no. 5 (May 1931). Includes bibliographical references (p. 353-356).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1969. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (Ph.D.)--Hong Kong University of Science and Technology, 2005. / Includes bibliographical references (leaves 149-169). Also available in electronic version.

Made available in DSpace on 2014-10-09T12:28:36Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:31Z (GMT). No. of bitstreams: 0 / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:28:36Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T13:57:31Z (GMT). No. of bitstreams: 0 / A doença de Chagas, zoonose causada pelo protozoário Trypanosoma cruzi, apresenta uma ampla distribuição na América Latina estendendo-se do Sul dos Estados Unidos até a Argentina. Estima-se existirem 10 milhões de pessoas infectadas e outras 25 milhões expostas ao risco. Apesar de descoberta há mais de um século, o mal de Chagas ainda é uma infecção grave que provoca grande impacto sócio-econômico, sem tratamento efetivo na fase crônica e que carece de conhecimentos científicos. O presente trabalho teve como objetivo a obtenção e o uso de linhagens consômicas de camundongos, na investigação da resistência. As linhagens consômicas foram produzidas por meio de acasalamentos programados e monitoração com marcadores polimórficos de DNA, onde um de seus cromossomos foi substituído pelo seu homólogo da outra linhagem. Como parentais foram utilizadas as linhagens isogênicas C57BL/6/J Unib, de fenótipo resistente (doadora) e A/JUnib, susceptível (receptora) empregadas na produção de cinco linhagens consômicas para os cromossomos 7 (CSs7), 11 (CSs11),14 (CSs14),17 (CSs17) e 19 (CSs19); descritos por Passos et al. (2003), como importantes no controle da infecção causada pela cepa Y do T.cruzi. Nos ensaios experimentais, os consômicos foram inoculados pela via i.p., com as doses de 101, 102, 103 e 104 empregando-se como controles animais de ambas as linhagens parentais. Em todos os consômicos, a resistência foi superior àquela observada no parental susceptível. Em um segundo protocolo, os consômicos foram acasalados com associações programadas e as progênies foram desafiadas empregando-se inóculos com doses crescentes de tripomastigotas. A resistência observada neste grupo foi também superior àquela observada no parental de fenótipo susceptível. Os resultados observados demonstram que o emprego das linhagens consômicas produzidas possibilitam avaliar a participação de cada cromossomo na resistência, bem como os efeitos da associação entre os cromossomos, que são uma estratégia eficiente no estudo de doenças multifatoriais de trato complexo, como a doença de Chagas. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Haldane's rule, which states that the heterogametic sex is preferentially afflicted if one of hybrid sexes is sterile or inviable, is a general pattern in all animals that possess sex chromosomes. The hybrid sterility component of this rule is especially important because hybrid sterility is involved in the onset of postzygotic isolation. Accumulating evidence on the fast evolution of individual sex genes have stimulated us to hypothesize that the fast evolution of sex genes may be the force underlying the excess of hybrid heterogametic sterility. This study tests the evolutionary patterns of sex genes in comparison to non-sex genes, as a general group. The divergences between a group of 19 sex genes and 20 non-sex genes from X chromosome were compared between D. melanogaster, D. mauritiana, D. simulans, and D. sechellia using PCR-RFLP. Within species polymorphism data were also obtained for D. simulans and D. mauritiana. The results show a significantly higher divergence for sex genes than non-sex genes, while a comparable level of intraspecific polymorphism was revealed in both groups. Among the sex gene group, genes related to male reproduction appear to evolve faster than femalereproductive genes. The evolution of both sex and non-sex genes conforms to the neutral theory under Tajima's test and HKA test. The faster evolution of sex genes supports the fast-sex theory as an explanation for the hybrid sterility component of Haldane's rule. Localization of some examples of hybrid sterility genes is crucial to ultimately untangle the genetics of hybrid sterility. The car region of D. mauritiana, which has been shown to harbor genes that confer full effect of hybrid sterility in the D. simulans genetic background, was introgressed into the D. simulans genome by continuous backcrosses. Recombination mapping analysis, taking advantage of molecular markers, revealed that at least two regions are capable of causing hybrid sterility in this species group. The phenotypes of hybrid testes were examined during the backcross process. / Thesis / Master of Science (MSc)

The World Health Organization estimates that vector-borne diseases account for 17% of the global burden of all infectious diseases and has identified the mosquito as the most dangerous of all disease-transmitting insects, being responsible for several million deaths and hundreds of millions of cases each year. The study of mosquito genomics provides a deeper understanding of the molecular mechanisms involved in every aspect of vector biology, such as sex determination, host-parasite interaction, ecology, feeding behavior, immunity and evolutionary trends and can be used for the development of new strategies for vector control. We developed the first map of the mitotic chromosomes of the major vector for West Nile fever and lymphatic filariasis, Culex quinquefasciatus. The map was then successfully utilized for mapping of approximately 90% of available genetic markers to their precise positions on the chromosomes. Idiograms were integrated with 140 genetic supercontigs representing 26.5% of the genome. A linear regression analysis demonstrated good overall correlation between the positioning of markers on physical and genetic linkage maps. This will improve gene annotation and help in distinguishing potential haplotype scaffolds and regions of segmental duplications. It will also facilitate identification of epidemiologically important genes that can be used as targets for the vector control and provide a better framework for comparative genomics that will help understanding of the evolution of epidemiologically important traits. In another study, we confirmed the presence of the newly described species, Anopheles daciae, in regions of Russia using molecular data. Although sympatric with its sibling species, Anopheles messeae, five nucleotide substitutions in the internal transcribed spacer 2 of ribosomal DNA can be used to distinguish the morphologically similar species. Chromosome rearrangements have a significant impact on mosquito adaptation and speciation. Using sequencing data in combination with karyotyping, we demonstrated that significant differences in inversion frequencies distinguish An. messeae from An. daciae, suggesting that these inversions are actively involved in adaptation and speciation. It is essential to have reliable toolbox for correct identification of these species and to know their range for future possible malaria outbreaks prevention. / Ph. D. / The more you study, the more you know The more you know, the more you forget The more you forget, the less you know So why study? According to the World Health Organization, mosquitoes are one of the deadliest animals in the world. They spread disease to humans resulting in hundreds of millions of illnesses and several million deaths every year. Study of the mosquito genome can help us understand vector biology and speciation and can be used to develop new strategies for vector control. Culex quinquefasciatus, the southern house mosquito, is one of the major vectors for the West Nile virus in the U.S. and for lymphatic filariasis, a disabling and disfiguring disease, worldwide. The traditional methods of control are of limited effectiveness because of high insecticide resistance in many populations of the mosquito. To enhance our resources for the control strategies, we developed physical maps of the chromosomes for this mosquito and effectively integrated it with available genetic linkage map. This work will help to identify epidemiologically important genes that can be used as targets for the vector control. Malaria vectors, mosquitoes from the genus Anopheles, are known for their ecological plasticity, which can be partially explained by chromosome rearrangements called inversion. A global malaria eradication program significantly reduced the number of deaths related to malaria, especially in Europe and the U.S. However, malaria outbreaks can occur anywhere competent vectors occur. We studied Anopheles messeae, one of the major European malaria vectors and its closely related species, Anopheles danciae. We report for the first time the presence of An. daciae in Russia and demonstrate that its distribution overlaps with that of An. messeae. Using genetic sequence data in combination with chromosome structure, we demonstrated that significant differences in inversion frequencies reliably distinguish An. messeae from An. daciae. These inversions may be involved in adaptation and speciation of these two species. It is essential to have reliable toolbox for correct identification of these species and to know their range for future possible malaria outbreaks prevention.