Supernumerary chromosome system, C-banding pattern characterization and multiple nucleolus organizer regions in Moenkhausia sanctaefilomenae (Pisces, Characidae)

Abstract

Chromosomes of Moenkhausia sanctaefilomenae (10 males and 20 females) collected from a tributary of the Tiet6 River (Botucatu, S.P. Brazil) were examined using kidney and testicular cells. Both males and females presented 2n = 50 chromosomes and 1 to 8 small supernumerary microchromosomes. C-banding demonstrated positively stained heterochromatic blocks in almost every chromosome and a pattern of interstitial bands located in the same position in relation to the centromere on the long arm of a large number of chromosomes. Two large NORs were detected in pair 19 of all the silver-stained metaphases; zero to 6 additional small NORs were detected in other chromosomes. A general survey of the occurrence of supernumerary chromosomes in fishes is presented.

Nuclear DNA content determination in Characiformes fish (Teleostei, Ostariophysi) from the Neotropical region

“…In the present study, Moenkhausia sanctaefilomenae specimens from the Miranda river (Mato Grosso do Sul) presented 2.39 ± 0.09 pg (Table I) while studies conducted in specimens of the same species from the Capivara river (São Paulo) showed that this latter sample exhibited 2.75 ± 0.25 pg (Carvalho et al, 1998). This difference may be related with the presence of 1 to 8 supernumerary microchromosomes observed in the sample from the Capivara river (Foresti et al, 1989). However, future studies are necessary to confirm the karyotypes of specimens from the Miranda river.…”

New cases of supernumerary chromosomes in characiform fishes

“…Other cases of extra chromosomes in fish are now well known (Venere and Galetti, 1985;Hochberg and Erdtmann, 1988;Oliveira et al, 1988;Foresti et al, 1989;Fenocchio and Bertollo, 1990;Oliveira and Foresti, 1993;Pastori et al, 1997). In Astyanax scabripinnis different populations have often shown one or two B chromosomes, or even up to five Bs, while several others showed none of these chromosomes (Salvador and Moreira-Filho, 1992;Maistro et al, 1992;Stange and Almeida-Toledo, 1993).…”

Occurrence of a Metacentric Macrochromosome B in Different Species of the Genus Astyanax (Pisces, Characidae, Tetragonopterinae).

“…On the other hand, there are several situations in which these chromosomes are frequent in the populations, as in Rhamdia hilarii (Fenocchio and Bertollo 1990), Prochilodus lineatus (=scrofa) (Pauls and Bertollo 1993) and Astyanax scabripinnis (Salvador and Moreira-Filho 1992, Maistro et al 1992, Souza and Moreira-Filho 1995, Vicente et al 1996, Mizoguchi and Martins-Santos 1997. They can vary widely in size, ranging from macrochromosomes as in Astyanax scabripinnis (Salvador andMoreira-Filho 1992, Maistro et al 1992) to microchromosomes as in Moenkhausia sanctaefilomenae (Foresti et al . 1989) and Prochilodus lineatus (=scrofa) (Pauls and Bertollo 1993).…”