The gene capicua is required for the establishment of dorsal-ventral polarity in the Drosophila melanogaster ovary. Loss of capicua function in the follicle cells results in dorsalization of both the embryo and eggshell. The most prominent dorsal features of the Drosophila eggshell are the dorsal appendages. We show that loss of capicua function results in the ventral ectopic specification of dorsal appendage-producing follicle cell fate. This cell fate change is due in part to the ectopic expression of genes such as mirror and Broad-Complex in capicua mutant ovaries. When either mirror or Broad-Complex are ectopically expressed independently of loss of capicua function, they generate a phenotype similar to the capicua mutant phenotype. We propose that Capicua normally acts in the ventral follicle cells to repress the expression of genes that pattern the dorsal follicle cells. EGF receptor signaling may normally inactivate Capicua repression in the dorsal follicle cells.

Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves 135-152).

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Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (doctoral)--Lund University, 1997. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:26:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-03-09Bitstream added on 2014-06-13T19:12:51Z : No. of bitstreams: 1 gomes_mo_me_sjrp.pdf: 699414 bytes, checksum: ee095f99dc71e8ce40b12d06b033a24f (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Uma questão central da evolução da resistência a inseticidas é o custo adaptativo do organismo contendo um genótipo que confere a resistência. O custo adaptativo refere-se à sobrevivência e à habilidade reprodutiva de um organismo. As mutações que conferem resistência aos inseticidas são preditas trazerem um custo na ausência dos mesmos e, consequentemente não se fixam nas populações. Entretanto, a resistência ao DDT em Drosophila melanogaster (DDT-R) está se aproximando de uma fixação global, mesmo após ter sido abolido o uso do DDT. Existem evidências consideráveis na literatura apoiando a hipótese que a resistência ao DDT baseada no metabolismo é poligênica em Drosophila e está parcialmente associada à superexpressão de genes do citocromo P450. Alguns trabalhos, entretanto consideram que a superexpressão de um único gene, Cyp6g1, associado com a inserção de um elemento transponível, Accord em D. melanogaster e Doc em D. simulans, é suficiente para promover a resistência, enquanto outros discutem que a superexpressão desse gene não confere necessariamente a resistência em D. melanogaster. O presente trabalho avaliou sete componentes do valor adaptativo (fertilidade, fecundidade, viabilidade ovo-pupa, viabilidade pupa-imago, viabilidade ovoimago, longevidade e o tempo de desenvolvimento) em quatro experimentos que diferiram quanto à metodologia. Essa análise teve por objetivo avaliar o custo dos fenótipos resistentes de linhagens recém coletadas e de laboratório de D. melanogaster e de D. simulans. Além disso, foi realizada uma análise do polimorfismo dos exons 1 e 2 do gene Cyp6g1, de linhagens resistentes e suscetíveis de laboratório, e resistentes recém coletadas dessas espécies, com o objetivo de examinar a relação entre o nível de suscetibilidade ao DDT e o polimorfismo. Foi verificado que, mesmo após um período de dois anos em... / A central matter of the evolution in insecticide resistance is the adaptive cost of the organism carrying a genotype that confers resistance. The adaptive cost refers to the survival and reproductive capacity of an organism. Mutations that confer pesticide resistance are predicted to carry a cost in the absence of the pesticide and consequently they are not fixed in the population. However, DDT resistance in Drosophila melanogaster (DDT-R) is closer to a global fixation, even after the suppression of DDT use. There is considerable evidence in the literature supporting the hypothesis that DDT resistance in Drosophila, based on metabolism, is poligenic and partially associated with overexpression of CYP genes. However, a recent study concluded that a single P450 gene, Cyp6g1, associated with the insertion of Accord element in the upstream region, in D. melanogaster, is sufficient to promote resistance. In a striking example of parallel evolution, the insertion of a different transposon, Doc element, is correlated with overtranscription of Cyp6g1 homolog in D. simulans and also show to be related to resistance. Other studies disagree that the overexpression of this gene necessarily confers resistance in D. melanogaster. Seven fitness components (fertility, fecundity, viability – egg-pupa, pupa-imago, egg-imago – developmental time and longevity) were evaluated in the present study, in four experiments that differed in methodology. This analysis aimed at evaluating the cost of the resistant phenotype in both species. In addition, the analysis of the polymorphism of exons 1 and 2 of Cyp6g1 gene of the susceptible and resistant strains of D. melanogaster and D. simulans was performed with the aim of examining the relationship between the degree of polymorphism and the susceptibility to DDT. D. melanogaster and D. simulans strains showed high intra and interspecific variability... (Complete abstract click electronic access below)

An organism's immune response may vary due to pathogen pressure in its environment, as well as due to interactions with other organisms. These factors, along with geographic rules (i.e. Gloger's rule) may influence the geographic distribution of the immune response within populations of a species. Here we use real-time quantitative PCR to measure the immune gene expression in six populations collected along the eastern U.S. of Drosophila melanogaster after mating. Antimicrobial genes did not show significant differences in expression due to location, whereas we did observe differences in anti-fungal and pro-phenoloxidase (anti-macromolecule) related genes. These differences in anti-macromolecule resistance are correlated with the latitude of the population opposite of which we would expect by Gloger's rule. We also determined that males and females from different populations tended to drive the differences we detected. Taken together, these results suggest that geographic factors influence genes involved in fungal and macro-pathogens defense post-mating.

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