The study of DNA sequence variation is a powerful approach to study genome evolution, and to reconstruct evolutionary histories of species. In this thesis, I have studied genetic variation in the fungus Neurospora tetrasperma and other closely related Neurospora species. I have focused on N. tetrasperma in my research because it has large regions of suppressed recombination on its mating-type chromosomes, had undergone a recent change in reproductive mode and is composed of multiple reproductively isolated lineages. Using DNA sequence data from a large sample set representing multiple species of Neurospora I estimated that N. tetrasperma evolved ~1 million years ago and that it is composed of at least 10 lineages. My analysis of the type of asexual spores produced using newly described N. tetrasperma populations in Britain revealed that lineages differ considerably in life history characteristics that may have consequences for their evolution. A comparative genomic analysis using three genomes of N. tetrasperma and the genome of N. crassa revealed that the mat a chromosomes in the lineages examine have been introgressed from other Neurospora species and that this introgression has reduced levels of molecular degeneration on the mating-type chromosomes. Finally, I generated a population genomic dataset composed of 92 N. tetrasperma genomes and two genomes of other Neurospora species. Analysis of these genomes revealed that all strains of N. tetrasperma have large regions of suppressed recombination on their mating-type chromosomes ranging from 69-84% of the chromosome and that the extent of divergence between mating-type chromosomes within lineages varies greatly (from 1.3 to 3.2%). I concluded that the source of this great divergence mating-type chromosome is large-scale introgression from other Neurospora species, and that these introgressed tracts have become fixed within N. tetrasperma lineages. I also discovered that genes within non-recombining introgressed regions of the mating-type chromosome have severely reduced levels of genetic variation as compared to the autosomes, and exhibit signatures of reduced molecular degeneration. My analysis of variation in coding regions revealed that positive selection on the introgressed regions has resulted in the removal of deleterious mutations and is responsible for the reductions in molecular degeneration observed.

Orientador: Edmir Daniel Carvalho / Banca: Mário Luiz Orsi / Banca: Angelo Antonio Agostinho / Resumo: Atualmente a implantação de sistemas de pisciculturas em tanques-rede, pode ser mais uma forma de impacto sobre a biota e a qualidade da água, das represas brasileiras. Esta atividade disponibiliza recursos como sobra de rações, efluentes e abrigo à ictiofauna residente. Assim, o presente trabalho tem como objetivo caracterizar a influência de sistemas de pisciculturas em tanques-rede sobre a dieta e dinâmica populacional de uma espécie de peixe nativo, Pimelodus maculatus (Pimelodidae, Siluriformes) a mais abundante nas adjacências desses empreendimentos na represa de Chavantes - SP/PR. Dos exemplares capturados na área de influência dos tanques-rede (Tanque) e na área referencial (Controle) foram obtidos os seguintes dados biológicos: comprimento padrão, peso total, sexo, grau de repleção estomacal. Ainda, os estômagos com itens alimentares foram retirados e fixados. Em termos de dieta, os itens foram pesados e identificados até o nível taxonômico mais inferior possível. A partir destes dados foram calculados o grau de repleção médio (GRM), atividade alimentar (Aa) e índice de importância alimentar (IAi), relação peso/comprimento, fator de condição, taxa de crescimento entre outros. Os resultados mostram que há diferenças quanto ao GRM, Aa e IAi entre os exemplares do trecho Tanque e Controle. Assim, para os exemplares do trecho Tanque a principal categoria alimentar é Ração (97,08), enquanto que para os exemplares do trecho Controle é Detrito (27,30), Insetos aquáticos (22,35), Vegetais (21,48) e Moluscos (21,46). Referente à dinâmica populacional com enfoque no crescimento estimou-se o fator de condição, relação peso/comprimento e taxas/curvas de crescimento em comprimento e peso. Os resultados demonstraram que no entorno dos tanques-redes, os valores de comprimento padrão e peso total são maiores em relação ao trecho Controle (p<0,0001)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The development of cage fish farming may be considered a new form of impact in the aquatic biota and water quality in Brazilian reservoirs. This activity provides resources to the resident fishes, as ration, effluent, and refuge. Thus, this work aims to characterize the influence of systems in cage fish farms in the diet and population dynamics of a native fish species, Pimelodus maculatus the most abundant in the vicinity of these enterprises in the Chavantes Reservoir - SP / PR. The standard length, weight, sex, degree of stomach fullness were obtained of specimens captured in the influence area of the cage farms (Cage farm) and the reference area (Control), and the stomachs with contents were removed and fixed. The food items were weighed and identified to the lowest possible taxonomic level. From these data were calculated the degree of fullness average (GRM), feeding activity (Aa) and Alimentary Index (AI), the weight/length, condition factor and growth rate. The results show that there are differences in the GRM, Aa and IAi between fishes from the Cage farm and Control stretches. Thus, Cage farm stretch presented Ration as its main food category (97.08), while in the diet of Control stretch fishes the main food resources were Detritus (27.30), Aquatic insects (22.35), Vegetal matter (21.48) and Molluscs (21.46). The population dynamics, focusing on growth were estimated the condition factor, weight/length relationship and rates/curves of growth in length and weight. The results demonstrated that for the Cage farm stretch, the values of standard length and total weight are larger in relation to Control stretch (p <0.0001). For the weight/length relationship there are significant differences between the stretches for males (t = 2.3301), females (t = 2.5853) and male + female + undefined (t = 3.5636), reinforced by the highest growth rate observed in the Cage farm stretch... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:30:13Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-02-20Bitstream added on 2014-06-13T21:00:35Z : No. of bitstreams: 1 ramos_ip_me_botib.pdf: 1690908 bytes, checksum: e5894e9a539c338fd7cd1881c08ebe73 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Atualmente a implantação de sistemas de pisciculturas em tanques-rede, pode ser mais uma forma de impacto sobre a biota e a qualidade da água, das represas brasileiras. Esta atividade disponibiliza recursos como sobra de rações, efluentes e abrigo à ictiofauna residente. Assim, o presente trabalho tem como objetivo caracterizar a influência de sistemas de pisciculturas em tanques-rede sobre a dieta e dinâmica populacional de uma espécie de peixe nativo, Pimelodus maculatus (Pimelodidae, Siluriformes) a mais abundante nas adjacências desses empreendimentos na represa de Chavantes – SP/PR. Dos exemplares capturados na área de influência dos tanques-rede (Tanque) e na área referencial (Controle) foram obtidos os seguintes dados biológicos: comprimento padrão, peso total, sexo, grau de repleção estomacal. Ainda, os estômagos com itens alimentares foram retirados e fixados. Em termos de dieta, os itens foram pesados e identificados até o nível taxonômico mais inferior possível. A partir destes dados foram calculados o grau de repleção médio (GRM), atividade alimentar (Aa) e índice de importância alimentar (IAi), relação peso/comprimento, fator de condição, taxa de crescimento entre outros. Os resultados mostram que há diferenças quanto ao GRM, Aa e IAi entre os exemplares do trecho Tanque e Controle. Assim, para os exemplares do trecho Tanque a principal categoria alimentar é Ração (97,08), enquanto que para os exemplares do trecho Controle é Detrito (27,30), Insetos aquáticos (22,35), Vegetais (21,48) e Moluscos (21,46). Referente à dinâmica populacional com enfoque no crescimento estimou-se o fator de condição, relação peso/comprimento e taxas/curvas de crescimento em comprimento e peso. Os resultados demonstraram que no entorno dos tanques-redes, os valores de comprimento padrão e peso total são maiores em relação ao trecho Controle (p<0,0001)... / The development of cage fish farming may be considered a new form of impact in the aquatic biota and water quality in Brazilian reservoirs. This activity provides resources to the resident fishes, as ration, effluent, and refuge. Thus, this work aims to characterize the influence of systems in cage fish farms in the diet and population dynamics of a native fish species, Pimelodus maculatus the most abundant in the vicinity of these enterprises in the Chavantes Reservoir - SP / PR. The standard length, weight, sex, degree of stomach fullness were obtained of specimens captured in the influence area of the cage farms (Cage farm) and the reference area (Control), and the stomachs with contents were removed and fixed. The food items were weighed and identified to the lowest possible taxonomic level. From these data were calculated the degree of fullness average (GRM), feeding activity (Aa) and Alimentary Index (AI), the weight/length, condition factor and growth rate. The results show that there are differences in the GRM, Aa and IAi between fishes from the Cage farm and Control stretches. Thus, Cage farm stretch presented Ration as its main food category (97.08), while in the diet of Control stretch fishes the main food resources were Detritus (27.30), Aquatic insects (22.35), Vegetal matter (21.48) and Molluscs (21.46). The population dynamics, focusing on growth were estimated the condition factor, weight/length relationship and rates/curves of growth in length and weight. The results demonstrated that for the Cage farm stretch, the values of standard length and total weight are larger in relation to Control stretch (p <0.0001). For the weight/length relationship there are significant differences between the stretches for males (t = 2.3301), females (t = 2.5853) and male + female + undefined (t = 3.5636), reinforced by the highest growth rate observed in the Cage farm stretch... (Complete abstract click electronic access below)

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-08-24T17:57:59Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertaçãosuper_final_(1).pdf: 1088878 bytes, checksum: f1d95f7419b99281751c7ea750e47cf8 (MD5) / Made available in DSpace on 2016-08-24T17:57:59Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertaçãosuper_final_(1).pdf: 1088878 bytes, checksum: f1d95f7419b99281751c7ea750e47cf8 (MD5) Previous issue date: 2011-08-31 / CAPES / Nesta dissertação é apresentada uma solução estacionária para um modelo de dinâmica populacional de uma única espécie, considerando a dispersão da população num espaço heterogêneo e um crescimento logístico da população. No primeiro capítulo, para dar ao leitor alguma intimidade com os conceitos apresentados estudamos alguns modelos de dinâmica populacional de uma única espécie. Referimo-nos a uma única população para dizer que não analisamos aqui a interação entre diversas espécies. No segundo capítulo concentra-se a parte substancial do nosso trabalho. Na seção 1 apresentamos o modelo, na seção 2 apresentamos a solução estacionária para o problema e na seção 3 fazemos uma discussão sobre efeitos de isolamento para uma população. / This thesis presents a stationary solution to a model of population dynamics of a single species, considering the dispersion of biological population in a heterogeneous space and a logistic population growth. In the rst chapter, to give the reader some familiarity with the concepts presented study some models of population dynamics of a single species. We refer to a single population to say we do not analyze the interaction between di erent species. The second chapter focuses on the substantial part of our work. In Section 1 presents the problem and the model, section 2 presents the stationary solution to the problem and in Section 3 we make a discussion about isolation e ects on a population