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Chromosome divergences between two sympatric characid fishes of the genus Bryconamericus

Adriane Pinto Wasko^I; Paulo Cesar Venere^II; Pedro Manoel Galetti Júnior^I

^IDepartamento de Genética e Evolução, Universidade Federal de São Carlos, Via Washington Luiz Km 235, 13565-905 São Carlos, SP, Brasil. Send correspondence to P.M.G. Jr.
^IIUniversidade Federal do Mato Grosso/ICLMA, Via MT 100 Km 03, 78600-000 Pontal do Araguaia, MT, Brasil

ABSTRACT

Cytogenetic studies were performed on two sympatric species of Bryconamericus which are awaiting more precise taxonomic identification. Although both Bryconamericus sp A and Bryconamericus sp B had a chromosome number equal to 52 chromosomes, their karyotypic structures varied widely. The two species presented multiple nucleolar organizer regions (NORs), at times varying in size. Centromeric heterochromatin was the most frequent type in the species studied and C banding showed no significant differences between karyotypes. The data permitted us to propose that non-Robertsonian chromosome rearrangements of the pericentric inversion type led to the differences between the two species of Bryconamericus.

Keywords: chromosome divergences; sympatric; characid fishes; Bryconamericus.

REFERENCES

Almeida Toledo, L.F. and Foresti, F. (1985). As regiões organizadoras de nucléolos em peixes. Cienc. Cult. 37: 448-453.

Bertollo, L.A.C., Takahashi, C.S. and Moreira Filho, O. (1978). Cytotaxonomic considerations on Hoplias lacerdae (Pisces, Erytrinidae). Rev. Bras. Genet. 1: 103-120.

Britski, H.A., Sato, Y. and Rosa, A.B.S. (1986). Manual de Identificação de Peixes da Região de Três Marias (com chave de identificação para os peixes da bacia do São Francisco). 3^a edição. CODEVASF-Divisão de Piscicultura e Pesca, Brasília, pp. 115.

Eigenmann, C.H. (1917). The American Characidae. Mem. Mus. Comp. Zool. 43: 1-102.

Fenocchio, A.S., Venere, P.C., Cesar, A.C.G., Dias, A.L. and Bertollo, L.A.C. (1991). Short term culture from solid tissues of fishes. Caryologia 44: 161-166.

Galetti Jr., P.M., Bertollo, L.A.C. and Moreira Filho, O. (1985). A ocorrência de NORs simples e múltiplas caracterizando diferentes grupos de peixes. XII Congresso Brasileiro de Zoologia. Resumos, pp. 175.

Galetti Jr., P.M., Cesar, A.C.G. and Venere, P.C. (1991). Heterochromatin and NORs variability in Leporinus fish (Anostomidae, Characiformes). Caryologia 44: 287-292.

Galetti Jr., P.M., Bertollo, L.A.C. and Moreira Filho, O. (1994). Trends in chromosome evolution of neotropical Characiform fishes. Caryologia 47: 289-297.

Howell, W.M. and Black, D.A. (1980). Controlled silver-staining of nucleolus organizer regions with a protective colloidal developer: a 1-step method. Experientia 36: 1014-1015.

Levan, A., Fredga, K. and Sandberg, A.A. (1964). Nomenclature for centromeric position on chromosomes. Hereditas 52: 201-220.

Maistro, E.L., Foresti, F., Oliveira, C. and Almeida Toledo, L.F. (1992). Occurrence of macro B chromosomes in Astyanax scabripinnis paranae (Pisces, Characiformes, Characidae). Genetica 87: 101-106.

Moreira Filho, O. and Bertollo, L.A.C. (1991). Astyanax scabripinnis (Pisces, Characidae): A species complex. Rev. Bras. Genet.14: 331-357.

Morelli, S. (1981). Aspectos citogenéticos do gênero Astyanax (Pisces, Characidae). Master's thesis, Departamento de Ciências Biológicas, Universidade Federal de São Carlos, São Carlos, SP.

Morelli, S., Bertollo, L.A.C., Foresti, F., Moreira Filho, O. and Toledo Filho, S.A. (1983). Cytogenetic considerations on the genus Astyanax (Pisces, Characidae). I. Karyotypic variability. Caryologia 36: 235-244.

Pauls, E. and Bertollo, L.A.C. (1991). Evidences for a system of supernumerary chromosomes in Prochilodus scrofa Steindachner, 1881 (Pisces, Prochilodontidae). Caryologia 36: 307-314.

Portela, A.L.B.S., Galetti Jr., P.M. and Bertollo, L.A.C. (1988). Considerations on chromosome evolution of Tetragonopterinae (Pisces, Characidae). Rev. Bras. Genet. 11: 307-316.

Salvador, L.B. and Moreira Filho, O. (1992). B chromosome in Astyanax scabripinnis (Pisces, Characidae). Heredity 69: 50-56.

Sumner, A.T. (1972). A simple technique for demonstrating centromeric heterochromatin. Exp. Cell Res. 75: 304-306.