Análise citogenética de peixes dos gêneros: Astyanax, Moenkhausia e Bryconops provenientes das regiões de Uberlândia-MG e Monte do Carmo-TO

Abstract

The family Characidae is the largest and most complex among the Characiformes, including the majority of freshwater fish in Brazil, with species varying considerably in size, weight, shape, diet and behavior. Recently, this group was listed as Incertae Sedis due to lack of consistent evidence of monophyly going to have only 12 subfamilies beyond those cited groups above. With the objective of raising information that can be useful to assist in the understanding of this complex ictiofauna, cytogenetic analysis were performed on species of Astyanax aff. fasciatus from the region of Uberlândia-MG, Astyanax sp, Astyanax aff. bimaculatus and Bryconops sp the region of Monte do Carmo-TO. A. fasciatus showed diploide number of 46 chromosomes and a system of multiple Ag-NORs, which proved to positively stained Chromomycin A3 (CMA3). Astyanax sp and Astyanax bimaculatus showed 50 chromosomes, being that in the first one if it verified the presence from 0 to 6 chromosomes B and a system Ag-NORs simple. These small farms if had also shown heterochromatic. Moreover, conspicuous centromeric and pericentromeric heterochromatics markings had been also observed, Astyanax bimaculatus presented system Ag-NORs multiple with up to three pairs marked, some of which also CMA3 +. C-banding revealed centromeric marks in almost all chromosomes. Bryconops sp presented 2n = 48 chromosomes, Ag-NORs simple coinciding with the markings CMA3 and centromeric heterochromatic blocks. These results go of meeting to the idea that the group previously treated as Tetragonopterinae encompasses a diversity to groups sufficiently accented what it is a consequence of its polifiletic nature.