Cariótipo e mapeamento cromossomico de seqüencias repetitivas em peixes marinhos com enfase em Tetraodontiformes do litoral paranaense

Abstract

Abstract: The upper rio Tibagi basin is located in the center-east of Paraná State and possess 65 main tributaries and headwater occur at East of Ponta Grossa region. It shows a great fish diversity with Characiformes and Siluriformes prevalence. The Astyanax altiparanae species is found in smaller tributaries of this basin. The upper rio Iguaçu basin is located in the left margin of the medium course of the rio Paraná, it possess 103 tributaries and headwater occur at East of the Serra do Mar mountain. It shows a poor ichthyofauna with high endemism degree, also with Characiformes and Siluriformes prevalence. Recently, Astyanax altiparanae has been found in the rio Iguaçu basin, being not registered up to 1983, for that it is discussed there origin. The Astyanax altiparanae species show diploid number with 2n=50 chromosomes and difference in their karyotypic formula and the chromosomes bearing the nucleolar organizing regions. In this work the Astyanax altiparanae karyotype of upper rio Tibagi and upper rio Iguaçu basins populations was characterized, using conventional stain with Giemsa, and differential with C-banding, Ag-NORs, base-specific fluorochrome (chromomycin A3) and in situ hybridization with rDNA 18S and 5S probes. Diagnostics morphometric characteristics in these two populations were analyzed to compose the axes of the free size canonical variables. The cytogenetics and morphological approaches were coincident and show comparable overlap of several markers among these populations and exclusiveness that reflect the level of isolated populations. Like This, and in opposition to studies that indicate gene flowamong A. altiparanae populations in the low rio Iguaçu with tributaries of the rio Paraná, it is waited that different populational stocks (regional variations) of this species occur along the basins of the Tibagi and Iguaçu rivers, individually, reflecting a complex evolutionary history.