科研之友
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摘要
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 geneticdiversity among groups in natural populations. Species of the Cichla genus, introduced in the upper Paran芍 river basin, present some genetic polymorphisms detected by RAPD and SPAR analyses. These species have been intercrossing and forming viable hybrids, withgreater 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 Paran芍 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 谷 informativo e possui altas taxas de conserva o ao longo do genoma dos eucariotos, possuindo caracter赤sticas 迆nicas que s o heredit芍rias. Estudos moleculares do gene DNAr 5S vem sendo realizados com diversos grupos, inclusive em algumas esp谷cies de peixes, com o intuito de solucionar problemas de rela es filogen谷ticas, padr o de ancestralidade e diversidade gen谷tica, entre grupos de popula es naturais. Esp谷cies do g那nero Cichla, introduzidas na bacia do alto rio Paran芍, apresentam polimorfismos gen谷ticos, detectados por an芍lise de RAPD e SPAR. Essas esp谷cies est o intercruzando-se e formando h赤bridos vi芍veis, com maior variabilidade gen谷tica. O objetivo desse trabalho foi padronizar ametodologia de amplifica o de regi es n o-transcritas da fam赤lia multig那nica rDNA 5S de Cichla e obter marcadores espec赤ficos para as esp谷cies parentais que pudessem, tamb谷m, ser identificados nos h赤bridos. Foram analisados 65 esp谷cimes de Cichla, das bacias do alto rio Paran芍 e Amaz nica. Apesar de n o se obter marcadores moleculares que pudessem ser 迆teis 角 identifica o de h赤bridos, foram obtidos marcadores moleculares gen谷ticos DNAr 5S esp谷cie-espec赤ficos para Cichla temensis, que podem ser utilizados para identifica o deexemplares dessa esp谷cie e, tamb谷m, marcadores populacionai
