Made available in DSpace on 2014-12-17T15:18:10Z (GMT). No. of bitstreams: 1 WashingtonCA.pdf: 849606 bytes, checksum: 5c75635780aa8bf93fa4262b0cf3a552 (MD5) Previous issue date: 2009-02-26 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Cytogenetic studies have been revealing a great diversity not detected, until then, in several families of fishes. Many of these groups, especially those that exhibit great diversity, like Perciformes and Siluriformes, possess species with difficult morphologic characterization, called cryptic species, commonly detected through karyotypic analyses, which reveals outstanding interespecific variations with relationship to the number and its chromosomal structures. Thus, the present work intends to contribute for the cytogenetic knowledge of marine and brackish fish species, because they peculiar life habits and by lack of cytogenetic data of your genetic aspects. Therefore, cytogenetic studies were developed in a species of Apogonidae (Perciformes), two species of sea catfishes of the family Ariidae (Siluriformes) and brackish fish Paurachenipterus galeatus (Siluriformes, Auchenipteridae), through C banding, Ag-NOR, use of base-specific flourochromes (DAPI and CMA3), as well as FISH (Fluorescent in situ hybridization) using ribosomal DNA probes 5S and 18S. The present results contribute to a better understanding of the processes of differentiation patterns and chromosome evolution in these groups. The use of other approaches (the morphology and molecular tools) will allow a larger understanding of the genetic and biological diversity of the Brazilian ichthyofauna. / Estudos citogen?ticos t?m revelado uma grande diversidade at? ent?o n?o detectada em diversas fam?lias de peixes. Muitos destes grupos, sobretudo os que exibem grande diversidade, como Perciformes e Siluriformes, possuem esp?cies de dif?cil caracteriza??o morfol?gica, chamadas de esp?cies cr?pticas, muitas vezes s? detectadas atrav?s de an?lises cariot?picas, as quais revelam varia??es interespec?ficas marcantes quanto ao n?mero e estrutura cromoss?mica. Desta forma, o presente trabalho pretende contribuir para o conhecimento citogen?tico de esp?cies marinhos e estuarinos, que, por n?o serem exploradas comercialmente ou terem h?bitos de vida peculiares s?o pouco estudadas quanto aos seus aspectos gen?ticos. Assim, an?lises cariot?picas foram desenvolvidas em uma esp?cie da fam?lia Apogonidae (Perciformes), em duas esp?cies de bagres marinhos da fam?lia Ariidae (Siluriformes), al?m de uma esp?cie de siluriforme estuarino, Paurachenipterus galeatus (Auchenipteridae) atrav?s de bandamento C, Ag-RONs, colora??o com DAPI e CMA3, bem como pela FISH (Fluorescent in situ hibridization), utilizando sondas ribossomais 5S e 18S. Os resultados aqui apresentados indicam grande diversidade inerente a estes grupos. Outras abordagens (an?lises morfol?gicas e ferramentas moleculares) permitir?o obter maior entendimento acerca da diversidade biol?gica da ictiofauna brasileira