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Genetics and Molecular Biology

Print version ISSN 1415-4757

Abstract

KAVALCO, Karine Frehner; BRANDAO, Karina de Oliveira; PAZZA, Rubens  and  ALMEIDA-TOLEDO, Lurdes Foresti de. Astyanax hastatus Myers, 1928 (Teleostei, Characidae): a new species complex within the genus Astyanax?. Genet. Mol. Biol. [online]. 2009, vol.32, n.3, pp. 477-483.  Epub July 03, 2009. ISSN 1415-4757.  http://dx.doi.org/10.1590/S1415-47572009005000055.

Four populations of Astyanax hastatus Myers 1928 from the Guapimirim River basin (Rio de Janeiro State) were analyzed and three distinct cytotypes identified. These cytotypes presented 2n = 50 chromosomes, with 4M+8SM+10ST+28A (Cytotype A), 8M+10SM+14ST+18A (Cytotype B), 6M+8SM+4ST+32A (Cytotype C) and scanty heterochromatin, mainly located throughout pericentromeric regions of several chromosomal pairs. No homologies with the As-51 satellite DNA were observed in the three cytotypes, although all of them presented multiple 18S rDNA sites, as detected by both silver nitrate staining and FISH (fluorescent in situ hybridization). The application of the term "species complex" in Astyanax is discussed from a cytotaxonomic viewpoint.

Keywords : Astyanax hastatus; molecular cytogenetics; karyotypic evolution; species complex.

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