Conserved 5S and variable 45S rDNA chromosomal localisation revealed by FISH in Astyanax scabripinnis (Pisces, Characidae).
Fluorescence in situ hybridisation (FISH) and double FISH experiments were carried out to ascertain the chromosomal distribution pattern of the 45S and 5S ribosomal (r) DNAs in four populations of the characid fish Astyanax scabripinnis--a group considered to be a species complex for its wide karyotypical and morphological diversity. The results regarding the 45S rDNA agreed with this hypothesis, since these sites showed intra- and inter-populational, numerical and positional variations. However, the data obtained with the 5S rDNA probe revealed a highly conserved chromosomal distribution pattern of these sequences among individuals of each population, as well as among the populations analysed. We consider this contrasting situation as a functional divergence between 45S and 5S ribosomal DNAs, which may reflect the localisation of these sequences in distinct nuclear compartments, leading them to undergo differentiated evolutionary processes.
Mantovani
Monique
M
Departamento de Genética e Evolução, Universidade Federal de São Carlos, Rodovia Washington Luís Km 235, Caixa Postal 676, CEP 13565-905, São Carlos-SP, Brazil.
Abel
Luciano Douglas dos Santos
LD
Moreira-Filho
Orlando
O
D000818:Animals; D002874:Chromosome Mapping / Q000662:veterinary; D004275:DNA, Ribosomal / Q000235:genetics*; D005399:Fishes / Q000235:genetics*; D017404:In Situ Hybridization, Fluorescence / Q000662:veterinary; D007621:Karyotyping / Q000662:veterinary; D009697:Nucleolus Organizer Region / Q000235:genetics
D004275:DNA, Ribosomal