Karyotypic characterization and NOR analysis by different banding techniques of Rhamdia quelen (Pisces, Pimelodidae) from the first plateau of the Iguaçu River (Brazil).
A population of R. quelen from the first plateau of the Iguaçu River (Paraná State, Brazil) was analyzed cytogenetically. A diploid set of 58 chromosomes was constituted by 32 M, 16 SM, 6 ST and 4 A (FN=116). In one individual a 2n=59 karyotype was determined due to the presence of one additional metacentric heterochromatic chromosome. NORs, detected by AgNO3 and CMA3 staining as well as fluorescence in situ hybridization with an 18S rDNA probe, are located at a terminal position on the short arms of a ST chromosome pair. C-banding marks the NORs and other weak bands distributed on telomeric regions of some chromosomes. These results give evidence that Rhamdia constitute, in terms of karyotypic macrostructure, a conserved group and support the idea that several synonymous species may be included in this genus.
UnaM, FCEQyN., Dept. Genetica, Felix de Azara 1552, 3300 Posadas, Mnes., Argentina. afenocch@fceqyn.unam.edu.ar
Alberto Sergio
AS
Fenocchio
Ana Cláudia
AC
Swarça
Marta Margarete
MM
Cestari
Ana Lúcia
AL
Dias
D000818:Animals; D001938:Brazil; D002871:Chromosome Banding; D002965:Classification; D004247:DNA / Q000032:analysis; D005260:Female; D005399:Fishes / Q000235:genetics*; D005828:Genetics, Population; D006570:Heterochromatin; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male
D006570:Heterochromatin; D004247:DNA