| Autor: |
Blanco, D. R., Lui, R. L., Vicari, M. R., Bertollo, L. A. C., Moreira-Filho, O. |
| Předmět: |
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| Zdroj: |
Cytogenetic & Genome Research; 2010, Vol. 132 Issue 1/2, p71-78, 8p, 3 Color Photographs, 2 Black and White Photographs |
| Abstrakt: |
Karyotype and cytogenetic characteristics of 2 species of giant trahiras, Hopliasintermedius, São Francisco river basin, and Hopliasaimara, Arinos river (Amazon basin), were examined by conventional (C-banding, Ag-NOR, DAPI/CMA3 double-staining) and fluorescent in situ hybridization (FISH) with 5S, 18S rDNA probes and cross-species Cot-1 DNA probing. Both species invariably had diploid chromosome number 2n = 50 and identical karyotypes composed of 10 pairs of metacentric and 15 pairs of submetacentric chromosomes. On the other hand, staining with base-specific fluorochromes (CMA3, DAPI) and FISH mapping of repetitive DNA sequences showed extensive interspecific differences: while the genome of H. aimara had one submetacentric pair bearing CMA3-positive (DAPI-negative) sites, that of H. intermedius had 4 such pairs; while FISH with a 5S rDNA probe showed one (likely homologous) signal-bearing pair, that with 18S rDNA displayed one signal-bearing pair in H. intermedius and 2 such pairs in H. aimara. Cross-species FISH probing with Cot-1 DNA prepared from total DNA of both species showed no signals of Cot-1 DNA from H. aimara on chromosomes of H. intermedius but reciprocally (Cot-1 DNA from H. intermedius on chromosomes of H. aimara) displayed signals on at least 4 chromosome pairs. Present findings indicate (i) different composition of repetitive sequences around centromeres, (ii) different NOR phenotypes and (iii) distinct taxonomic status of both giant trahira species. Copyright © 2010 S. Karger AG, Basel [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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