Análise citogenética em três espécies do gênero Astyanax (Pisces; Characiformes)

• Autor(a) principal: Abelini, Edner
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1352
• topic: Citogenética; Peixes; Astyanax scabripinnis; Astyanax fasciatus; Astyanax altiparanae; Banda-C; NOR; Cariótipo; Paraná; (Estado); Brasil.; Citogenetic; Astyanax; C-banding; NOR; Cariotipic; Paraná; State; Brazil.; Ciências Agrárias; Agronomia

Cytogenetics studies were conducted on three species of the genus Astyanax: Astyanax scabripinnis (Tagaçaba stream and Tauá stream), Astyanax altiparanae (Iguaçu river and Maringá stream) and Astyanax fasciatus (Maringá stream). Both populations of Astyanax scabripinnis showed 2n=50 chromosomes, while the population from Tagaçaba stream showed karyotipic formulae comprising 10M, 22SM, 6ST and 12A (NF=88) and simple-NOR system, the other population, from Tauá stream showed karyotipic formulae with 10M, 18SM, 8ST and 14A (NF=86) and multiple-NOR system, by analisys Ag-NOR. However, with the use of FISH tecnique in population from Tagaçaba it were possible detect genes rDNA in 14 chromosome, over there bitelomeric markes in one chromosome. This data indicates that the only NOR chromosome pair is being expressed in this population. The constitutive heterochromatin standard showed also difference betweent the two populations, with pericentromeric markings in the majority of the chromosomes of the population from Tagaçaba and with large telomeric blocks for population from Tauá. Besides Tagaçaba showed macrochromosome B in 50% of female analyzed. Both population of Astyanax altiparanae showed 2n=50 chromosomes, but differed in karyotipical formulae. The population from Iguaçu river showed 10M, 26SM, 6ST and 8A (NF=92) while the population of Maringá stream exhibited karyotypic formulae 10M, 22SM, 6ST and 12A (NF=88). Both population presented multiple-NOR with five and three markes, respectively and a constitutive heterocromatin standard very similar, with markers in the majority of the chromosomes in pericentromeric regions, telomeric, over there interstitial blocks next to centromere. In population of Astyanax fasciatus from Maringá stream was reported the diploid number 2n=46 chromosomes with karyotipic formulae 14M, 10SM, 12ST and 10A (NF=82) with simple-NOR system and heterocromatin standard with obvious markes in a telomeric regions in several chromosome subtelocentrics and acrocentrics characteristic of the specie. The data showed for this species differ in relation to diploid number for some populations analysed (2n=48 chromosome) and karyotipic formulae for those with the same diploid number. The present data showed for three species collaborate with aspects basics characteristic of the group indicating a complex of the species for each of theirs. However, a standarting of data using techniques more resolutives should be considerated for the best definition of existence of differents units taxonomics.