caa a22 4500 477089801 CHVBK 20180405111513.0 cr unu---uuuuu 170330e19960601xx s 000 0 eng 10.1007/BF02263681 doi (NATIONALLICENCE)springer-10.1007/BF02263681 Fluorescence in situ hybridization with rDNA probes on chromosomes of two nucleolus organizer region phenotypes of a species of Eigenmannia (Pisces, Gymnotoidei, Sternopygidae) [Elektronische Daten] [Lurdes de Almeida-Toledo, Ann Stocker, Fausto Foresti, Silvio de Almeida Toledo-Filho] Nucleolus organizer regions (NORs) were analysed in two related and geographically close populations ofEigenmannia sp. 1 (Pisces, Gymnotoidei, Sternopygidae) using silver staining and fluorescencein situ hybridization (FISH). The two populations differed in their Ag-NOR phenotypes, displaying fixed differences in the NOR-bearing chromosome pairs. FISH with rDNA probes showed that these differences were due to the location of rDNA cistrons. This finding, showing fixed NOR differences between two populations belonging to the same species in a connected river system, is highly significant in terms of evolutionary change, possibly indicating an initial step of genetic differentiation. This result also has important implications from the cytosystematic point of view, as NORs usually have a very constant karyotypic location in fish species and have been used as species-specific chromosome markers. Rapid Science Publishers, 1996 cytogenetics nationallicence fluorescence in situ hybridization nationallicence Gymnotoidei nationallicence nucleolus organizer region nationallicence Pisces nationallicence de Almeida-Toledo Lurdes Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11.461-05422-970, São Paulo, SP, Brazil aut Stocker Ann Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11.461-05422-970, São Paulo, SP, Brazil aut Foresti Fausto Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11.461-05422-970, São Paulo, SP, Brazil aut de Almeida Toledo-Filho Silvio Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11.461-05422-970, São Paulo, SP, Brazil aut Chromosome Research Kluwer Academic Publishers 4/4(1996-06-01), 301-305 0967-3849 4:4<301 1996 4 10577 https://doi.org/10.1007/BF02263681 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02263681 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- de Almeida-Toledo Lurdes Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11.461-05422-970, São Paulo, SP, Brazil aut NATIONALLICENCE 700 1- Stocker Ann Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11.461-05422-970, São Paulo, SP, Brazil aut NATIONALLICENCE 700 1- Foresti Fausto Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11.461-05422-970, São Paulo, SP, Brazil aut NATIONALLICENCE 700 1- de Almeida Toledo-Filho Silvio Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, Caixa Postal 11.461-05422-970, São Paulo, SP, Brazil aut NATIONALLICENCE 773 0- Chromosome Research Kluwer Academic Publishers 4/4(1996-06-01), 301-305 0967-3849 4:4<301 1996 4 10577 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer