Chromosomal diversity in three species of electric fish (Apteronotidae,Gymnotiformes) from the Amazon Basin |
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Authors: | Fernando Henrique Ramos Silva Julio Cesar Pieczarka Adauto Lima Cardoso Patrícia Corrêa da Silva Jonas Alves de Oliveira Cleusa Yoshiko Nagamachi |
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Institution: | 1.Instituto de Ciências Biológicas, Universidade Federal do Pará, Belém, PA, Brazil.;2.Instituto de Desenvolvimento Sustentável Mamirauá, Tefé, AM, Brazil. |
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Abstract: | Cytogenetic studies were carried out on samples of Parapteronotus hasemani, Sternarchogiton preto and Sternarchorhamphus muelleri (Apteronotidae, Gymnotiformes) from the Amazon basin. The first two species exhibited both a 2n = 52 karyotype, but differed in their karyotypic formulae, distribution of constitutive heterochromatin, and chromosomal location of the NOR. The third species, Sternarchorhamphus muelleri, was found to have a 2n = 32 karyotype. In all three species the DAPI and chromomycin A3 staining results were consistent with the C-banding results and nucleolar organizer region (NOR) localization. The 18S rDNA probe confirmed that there was only one pair of ribosomal DNA cistron bearers per species. The telomeric probe did not reveal interstitial telomeric sequences (ITS). The karyotypic differences among these species can be used for taxonomic identification. These data will be useful in future studies of these fishes and help understanding the phylogenetic relationships and chromosomal evolution of the Apteronotidae. |
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Keywords: | fluorochromes FISH chromosomal rearrangements biodiversity |
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