L.B. Ribeiro, D.A. Matoso, M.C. Almeida, M.R. Vicari, A. Moraes-Neto, M.C.C.M. Svidnicki, R.F. Artoni
Published: August 14, 2008
Genet. Mol. Res. 7 (3) : 718-724
DOI: https://doi.org/10.4238/vol7-3gmr456

Cite this Article:
L.B. Ribeiro, D.A. Matoso, M.C. Almeida, M.R. Vicari, A. Moraes-Neto, M.C.C.M. Svidnicki, R.F. Artoni (2008). Karyotypic variability in Iheringichthys labrosus (Teleostei, Pimelodidae) from the Tibagi River basin (Paraná State, Brazil). Genet. Mol. Res. 7(3): 718-724. https://doi.org/10.4238/vol7-3gmr456

About the Authors
L.B. Ribeiro, D.A. Matoso, M.C. Almeida, M.R. Vicari, A. Moraes-Neto, M.C.C.M. Svidnicki, R.F. Artoni

Corresponding Author
R.F. Artoni
Email: rfartoni@pesquisador.cnpq.br

ABSTRACT

Cytogenetic analyses were carried out in a populational sample of Iheringichthys labrosus from the Guaraúna River (Upper Tibagi River; Paraná State, Brazil) in order to provide a karyotypic comparison with another previously studied population from the Lower Tibagi River, characterized by the presence of 32m + 8sm + 6st + 10a (2n = 56, FN = 102) and occurrence of supernumerary chromosomes (80% of individuals). The 17 specimens of I. labrosus (6 females, 10 males and 1 of unknown sex) from the Upper Tibagi River showed 2n = 56 chromosomes, a karyotype formula of 14m + 32sm + 4st + 6a (FN = 106), without evidence of sex chromosome heteromorphism or supernumerary chromosomes. The heterochromatin was detected at telomeric and centromeric positions in several chromosomal pairs. The Ag-nucleolar organizer regions were heteromorphic and located at terminal position on short arms of the 16th chromosomal pair, suggesting a positive association with heterochromatic regions. The inter-populational karyotypic differentiation reported indicates distinct evolutionary pathways within I. labrosus in the Tibagi River basin.

Key words: cytotaxonomy, Heterochromatin, karyotypic evolution, Ag-nucleolar organizer regions.