RESUMO
Characidae is the largest and more diversified family from Characiformes and presents several classification problems, with several genera currently allocated as incertae sedis, such as the genus Hemigrammus. The upper Paraná river floodplain is an environment with high fish diversity. There is at least one species of Hemigrammus, however there are divergences among some authors about the number and the identification of the species from this genus. Therefore the goal of this study was to characterize, using a molecular approach, individuals of Hemigrammus from the upper Paraná river floodplain and to compare them with individuals from the type locality of Hemigrammus marginatus, since this is the only species distributed in this floodplain. For this, the DNA was extracted and a partial region from the mitochondrial genes ATPase 6 and ATPase 8 were amplified and sequenced. The results evidenced the existence of two species of Hemigrammus in the floodplain, although impossible to be distinguished only through morphological traits. High nucleotide diversity among individuals from the upper Paraná river in relation to those from the type locality was also observed, indicating that both species of Hemigrammus present in the upper Paraná river floodplain are not Hemigrammus marginatus.
RESUMO
The 5S rDNA gene is informative and has high conservation rates along the eukaryotic genome, having unique hereditary characteristics. Molecular studies with the 5S rDNA gene have been carried out with several groups, including some species of fish, aiming at solving phylogenetic relationship problems, ancestral patterns and genetic diversity among groups in natural populations. Species of the Cichla genus, introduced in the Upper Paraná River basin, present some genetic polymorphisms detected by RAPD and SPAR analyses. These species have been intercrossing and forming viable hybrids, with greater genetic variability. The objective of this work was to standardize the amplification methodology for the non-transcribed regions of 5S rDNA multigenic family of Cichla, and to obtain specific markers for parent species that could also be identified in the hybrids. Sixty-five specimens of Cichla collected from the Upper Paraná River and Amazon basins were analyzed. Although molecular markers that could be useful in the identification of hybrids were not obtained, genetic molecular 5S rDNA species-specific markers for Cichla temensis that can be employed to identify of this species, as well population markers that can be useful in population genetic variability studies, were obtained
O gene DNAr 5S é informativo e possui altas taxas de conservação ao longo do genoma dos eucariotos, possuindo características únicas que são hereditárias. Estudos moleculares do gene DNAr 5S vem sendo realizados com diversos grupos, inclusive em algumas espécies de peixes, com o intuito de solucionar problemas de relações filogenéticas, padrão de ancestralidade e diversidade genética, entre grupos de populações naturais. Espécies do gênero Cichla, introduzidas na bacia do alto rio Paraná, apresentam polimorfismos genéticos, detectados por análise de RAPD e SPAR. Essas espécies estão intercruzando-se e formando híbridos viáveis, com maior variabilidade genética. O objetivo desse trabalho foi padronizar a metodologia de amplificação de regiões não-transcritas da família multigênica rDNA 5S de Cichla e obter marcadores específicos para as espécies parentais que pudessem, também, ser identificados nos híbridos. Foram analisados 65 espécimes de Cichla, das bacias do alto rio Paraná e Amazônica. Apesar de não se obter marcadores moleculares que pudessem ser úteis à identificação de híbridos, foram obtidos marcadores moleculares genéticos DNAr 5S espécie-específicos para Cichla temensis, que podem ser utilizados para identificação de exemplares dessa espécie e, também, marcadores populacionais, que podem ser úteis para estudos de variabilidade genética populacional
RESUMO
The purpose of the present study was to verify, using RAPD and ISSR molecular techniques associated with the morphological characterization of bivalve shells, if the morphologically distinct specimens of Corbicula fluminea sampled at Rosana Reservoir belong to different species. The foot muscle tissue of the three groups (G1, G2, and G3) of Corbicula was removed and frozen in liquid nitrogen to the DNA analyze. Morphometric variables of the shell indicated significant differences among the specimens of Corbicula. On the other hand, molecular analyses revealed genetic similarity among the specimens, showing the nonexistence of molecular polymorphism. The data confirmed that the two morphologically different groups also belong to the species C. fluminea, showing the occurrence of phenotypic plasticity, probably caused by environmental or biotic factors
O objetivo do presente estudo foi verificar através de técnicas moleculares, RAPD e ISSR aliadas à caracterização morfológica da concha dos bivalves, se os indivíduos morfologicamente distintos de Corbicula fluminea amostrados no reservatório de Rosana pertencem a espécies diferentes. O tecido muscular do pé dos três grupos (G1, G2 e G3) de Corbicula foi removido e congelado em nitrogênio líquido para a análise do DNA. As variáveis morfométricas das conchas indicaram diferenças significativas entre os indivíduos de Corbicula. Por outro lado, as análises moleculares revelaram similaridade genética, evidenciando a não existência de polimorfismo molecular. Os resultados confirmam que os dois grupos diferentes morfologicamente também pertencem a espécie C. fluminea, demonstrando a ocorrência de plasticidade fenotípica, provavelmente causada por fatores bióticos ou ambientais
RESUMO
Lonchocarpus cultratus (Vell.) A.M.G. Azevedo and H.C. Lima is an important plant species in areas of natural reforesting in South and Southeastern Brazil, including riparian areas. This arboreous species seems to reproduce by seeds in undisturbed forests. In regenerating forests, however, L. cultratus has been observed mostly as patches of aggregates, consisting of highly similar plants, resembling clones. Sprouting from root buds had been previously observed in L. cultratus in a forest affected by fire. In the present study, RAPD polymorphism revealed high genetic diversity among plants from L. cultratus aggregates in a natural restoring riparian forest affected by fires, in the Upper Paraná River, Brazil. These data allow the suggestion that sexual reproduction has been the L. cultratus usual reproductive strategy to colonize the reforesting riparian area
No Sul e Sudeste do Brasil, Lonchocarpus cultratus (Vell.) A.M.G. Azevedo e H.C. Lima é uma espécie arbórea importante para o reflorestamento natural, incluindo áreas ripárias. Em florestas regeneradas, diferentemente de florestas não perturbadas, esta espécie tem sido observada como agregados de plantas semelhantes entre si, ao ponto de ter sido formulada a hipótese de serem clones. Em um estudo prévio, brotamento de raízes foi observado em L. cultratus, em uma floresta afetada pelo fogo. No presente estudo, análises de polimorfismo de RAPD revelaram alta diversidade genética entre as plantas de agregados de L. cultratus, em uma floresta ripária afetada pelo fogo, no alto rio Paraná. Os dados permitem sugerir que reprodução sexual tem sido a usual estratégia reprodutiva de colonização de L. cultratus, nesta área de reflorestamento natural