RESUMO
Chromosomal inversions are present in a wide range of animals and plants, having an important role in adaptation and speciation. Although empirical evidence of their adaptive value is abundant, the role of different processes underlying evolution of chromosomal polymorphisms is not fully understood. History and selection are likely to shape inversion polymorphism variation to an extent yet largely unknown. Here, we perform a real-time evolution study addressing the role of historical constraints and selection in the evolution of these polymorphisms. We founded laboratory populations of Drosophila subobscura derived from three locations along the European cline and followed the evolutionary dynamics of inversion polymorphisms throughout the first 40 generations. At the beginning, populations were highly differentiated and remained so throughout generations. We report evidence of positive selection for some inversions, variable between foundations. Signs of negative selection were more frequent, in particular for most cold-climate standard inversions across the three foundations. We found that previously observed convergence at the phenotypic level in these populations was not associated with convergence in inversion frequencies. In conclusion, our study shows that selection has shaped the evolutionary dynamics of inversion frequencies, but doing so within the constraints imposed by previous history. Both history and selection are therefore fundamental to predict the evolutionary potential of different populations to respond to global environmental changes.
Assuntos
Adaptação Biológica/genética , Evolução Biológica , Inversão Cromossômica/genética , Drosophila/genética , Variação Genética , Modelos Genéticos , Seleção Genética , Animais , Mudança Climática , França , Países Baixos , PortugalRESUMO
O liquido cefalo-raquiano pode adentrar o ouvido medio devido traumatismos, anomalias congenitas, tumores invasivos, infeccoes e causas iatrogenicas, entretanto sao eventos raros dentro da literatura mundial. Dentre as congenitas a via de acesso pode ser atraves do tegmen, celulas mastoideias, canal auditivo interno e aqueduto da coclea. Pode ocorrer otorreia se a membrana timpanica nao estiver integra ou rinorreia se a mesma conservar sua integridade. A audicao podera sofrer variacoes de perda dependendo do comprometimento coclear o mesmo acontecendo com o labirinto posterior. Essas fistulas permitem a entrada de germes para o endocraneo podendo provocar meningites em graus variaveis de intensidade e frequencia. O diagnostico pode ser provocado pela presenca de otorreia ou rinorreia liquorica, disacusias neurosensoriais ou mixtas e meningites repetitivas. Esses quadros isolados ou associados permitem a exploracao radiologica que vem trazer a informacao objetiva da patologia congenita e seu trajeto fistuloso. O tratamento e cirurgico consistindo no fechamento da fistula
