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Comparative Cytogenetics and Molecular Phylogeography in the Group <i>Astyanax altiparanae – Astyanax </i>aff. <i>bimaculatus</i> (Teleostei, Characidae)

2011; Karger Publishers; Volume: 134; Issue: 2 Linguagem: Inglês

10.1159/000325539

ISSN

1424-8581

Autores

Karine Frehner Kavalco, Rubens Pazza, Karina O. Brandão, Caroline Garcia, Lurdes Foresti de Almeida-Toledo,

Tópico(s)

CRISPR and Genetic Engineering

Resumo

The genus <i>Astyanax</i> comprises small characin fish of the neotropical region. The so-called ‘yellow-tailed characins’ compose one of the most widely distributed <i>Astyanax</i> groups. <i>A. altiparanae</i> and <i>A. </i>aff. <i>bimaculatus</i>, are evolutionarily closely related and commonly found in several Brazilian hydrographic basins. In the present work, chromosomal data of specimens of <i>A. altiparanae</i> and <i>A. </i>aff. <i>bimaculatus</i> from 4 hydrographic basins in the states of São Paulo (Upper Tietê, Paranapanema, Ribeira de Iguape) and Rio de Janeiro (Guapimirim) are shown. All the populations showed 50 chromosomes, with different karyotypic formula. Although only a single Ag-NOR bearing chromosome pair was observed, all populations possess multiple cistrons of 18S rDNA. FISH with the 5S rDNA probe showed single signals at the interstitial position of one metacentric chromosome pair. C-bands are distributed in the terminal and interstitial regions of several chromosomes. However, the As-51 satDNA are frugally located in a few chromosomes of fishes from Upper Tietê, Paranapanema and Guapimirim Rivers, being absent in individuals of <i>A.</i> aff. <i>bimaculatus</i> from Ribeira de Iguape River basin. Beside these 4 populations, molecular phylogeography studies were also performed in individuals from Middle and Lower Tietê River basin and from 2 additional collection sites in the Paranapanema and Ribeira de Iguape River basins. The phylogeographic analysis using 2 mtDNA regions (totalizing 1.314 bp of <i>ND2</i> and <i>ATPase6/8</i> genes) of 8 populations of the group of ‘yellow-tailed characins’ from 3 major hydrographic basins showed structuring of populations, suggesting a correlation between chromosomal (nuclear) and molecular (mitochondrial) data.

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