Made available in DSpace on 2015-09-17T15:24:09Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-12-17. Added 1 bitstream(s) on 2015-09-17T15:48:17Z : No. of bitstreams: 1 000846655.pdf: 1588788 bytes, checksum: ca68d5412270b7e10f44b091129d9d94 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / D. melanogaster e D. simulans são espécies irmãs nativas da África tropical que divergiram de um ancestral comum a cerca de dois Myr. Estas espécies têm sido comparadas em vários traços, incluindo a morfologia, fisiologia, comportamento sexual, aloenzimas e outras proteínas, inversões cromossômicas, DNA nuclear e mitocondrial, elementos transponíveis, infecção por Wolbachia entre outros. Entretanto, estudos em populações da América do Sul, inclusive do Brasil, são escassos. O objetivo principal do trabalho foi comparar linhagens geográficas de D. melanogaster e D. simulans do Brasil, África e França, quanto à suscetibilidade ao inseticida DDT, ao padrão de beta e alfa esterases, principalmente em relação à frequência do polimorfismo da esterase- 6 em indivíduos fenotipados como resistentes e suscetíveis, e a atividade da glutationa S-transferase. Ambas as espécies mostraram uma ampla variabilidade nos valores da CL50 obtidos. Os maiores valores foram observados nas linhagens africanas de D. melanogaster e D. simulans, TANA (447,89 μg/mL), e TANA-4 (920 μg/mL). A linhagem Canton-S de D. melanogaster foi a que apresentou o menor valor de CL50 = 2,99 μg/mL. Comparando as populações de mesma localidade de ambas as espécies verifica-se que as linhagens de D. melanogaster mostraram valores de CL50 maiores que os de D. simulans, com exceção da linhagem FLO onde D. simulans apresentou um valor de CL50 (94,60) ligeiramente superior ao de D. melanogaster (81,82). Foram analisadas duas bandas α-esterásicas, denominadas de α-1 e α-2, sendo que a banda α-2 foi observada em 100% de todos os indivíduos analisados de ambas as espécies. Os dados mostram maior variabilidade genética para D. melanogaster em relação à resistência ao DDT, alta resistência para as linhagens africanas de ambas as espécies, indicando que estas populações continuam sendo selecionadas por este... / D. melanogaster and D. simulans are sister species native to tropical Africa which diverged from a common ancestor about two Myr. These species have been compared in several traits, including morphology, physiology, sexual behavior, allozymes and other proteins, chromosomal inversions, nuclear and mitochondrial DNA, transposable elements, Wolbachia infection among others. However, studies in populations of South America, including Brazil, are scarce. The main objective of the study was to compare geographic strains of D. melanogaster and D. simulans from Brazil, Africa and France, for susceptibility to the insecticide DDT, the pattern of α and β esterases, especially in relation to the frequency of the polymorphism of esterase-6 in individuals phenotyped as resistant and susceptible, and the activity of glutathione-S-transferase . Both species showed a wide variability in LC50 values obtained. The highest values were observed in African strains of D. melanogaster and D. simulans, TANA (447.89 mg / mL), and TANA-4 (920 / mL). The Canton-S strain of D. melanogaster was the one with the lowest LC50 = 2.99 mg / mL. Comparing populations from the same location of both species the strains of D. melanogaster showed LC50 values larger than D. simulans, except FLO D. simulans strain had a LC50 (94.60) slightly higher than D. melanogaster (81.82). We analyzed two bands α-esterases, which we call α-1 and α-2, and the band α-2 was observed in 100% of all individuals analyzed in both species. The data show greater genetic variability for D. melanogaster for resistance to DDT, high resistance to African strains of both species, indicating that these populations continue to be selected by this or another insecticide, the lack of a cline for the F and S alleles in strains of both species, suggest that treatment with DDT may have selected individuals heterozygous for some strains, which may have masked the...

<p>Haldane’s rule states “when in the F1 offspring of two different animal races one sex is absent, rare, or sterile, that sex is the heterozygous sex”. Many studies regarding hybrid male sterility and in-viability have been done in order to better understand the process of speciation in males. Yet the study of speciation in hybrid females has been largely ignored. In our study we re-examined the extent of fertility in F1 reciprocal females of hybridization between <em>Drosophila simulans and D. mauritiana</em> species<em>.</em> Hybridization between these species produces fertile females and sterile males. Our goal was to address the following questions: 1. Are F1 hybrid females fully fertile? 2. Are there any maternal effects observed in reciprocal female hybrids? 3. Are there significant differences in ovariole numbers between the reciprocal hybrids? and 4. What is the state of the hybrid ovaries as a function of age? In order to answer these questions we looked at the level of oviposition and egg hatchability and the differences in ovariole numbers in pure species and F1 females. Our results indicated that the reciprocal hybrid females are not only fully fertile but they also showed heterosis. The heterosis observed in the hybrids can be attributed in part to the presence of maternal effects. The reciprocal hybrids also showed differences in ovariole number compared to each other and to the parental species. Our findings signify the importance of maternal effects as a potentially powerful mechanism for moderating the rates of evolution of speciation in hybrid females.</p> / Master of Science (MSc)