Polimorfismos no rDNA em uma planta de genoma reduzido Utricularia gibba L. (Lentibulariaceae): evolução em concerto incompleta e sua implicação na inferência filogenética
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Data
2016-07-29
Autores
Franco Marulanda, Néstor Darío [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
A planta carnívora Utricularia gibba (Lentibulariaceae) apresenta um genoma reduzido de aproximadamente 82 Mpb e foi empregada no presente estudo para se investigar a diversidade de cópias da região ITS (nrDNA). Uma das características do nrDNA é que suas cópias em tandem apresentam alto grau de similaridade pela ação homogeneizadora da evolução em concerto. Porém, neste estudo foram encontradas variações intragenômicas, intra e interpopulacionais nas regiões ITS em U. gibba. Com o objetivo de elucidar o impacto dos polimorfismos nos espaçadores ITS1, ITS2 e no gene 5,8S nas análises filogenéticas e filogeográficas, foi clonada a região ITS completa de 25 indivíduos de 5 populações, assim obtidos 292 cópias as quais foram analisadas isoladamente cada região (ITS1, 5,8S e ITS2) e em conjunto. Desta forma foram avaliados o comprimento e o conteúdo das regiões, as variações nucleotídicas e haplotípicas e realizadas análises filogenéticas e filogeográficas. Para determinar a funcionalidade das sequências obtidas foram identificados motifs conservados das regiões ITS1 e 5,8S e para os haplótipos da região ITS2 foi confirmada a sua estrutura secundária por transferibilidade das hélices em estruturas secundárias conhecidas de espécies filogeneticamente relacionadas. Assim, as três regiões apresentaram polimorfismos representados em haplótipos para cada sequência. Os resultados sugerem que todos os diferentes haplótipos presentes em U. gibba são cópias funcionais que podem ser usadas como marcadores filogenéticos para o nível de espécie, seja de forma isolada ou a região completa (ITS1+5,8S+ITS2). Entretanto, em análises filogenéticas e filogeográficas podem ser gerados artefatos e histórias evolutivas errôneas quando comparadas populações dentro de uma mesma espécie, dada à presença de haplótipos compartilhados por indivíduos de diferentes populações.
The aquatic carnivorous plant, Utricularia gibba (Lentibulariaceae) has a small genome of with approximately 82 Mpb and was used in this work for the variance analysis of the copies diversity of the ribosomal DNA ITS region (nrDNA). One of the nrDNA features is that its its copies in tandem ys have present a high degree of similarity in intra individual and interspecies genomes due the homogenizing action of concerted evolution. However, in this study intragenomic, intra, and inter-populational variations were found in ITS1 + 5.8S + ITS2 ITS regions in individuals and populations evaluated. U. gibba. With the main objectiveaim of to elucidate the impact of polymorphisms of thein the intergenic spacers ITS1, ITS2, and gene 5.8S and ITS2 regions in phylogenetic and phylogeographic analyszes, we was cloned the complete ITS region of 25 individuals from 5 populations, thereby obtained 292 clones copies and internal spacers ITS1 and ITS2 and the 5.8S gene were identified, which were analyzed individually (ITS1, 5.8S, and ITS2) and togetherconcatenated. Thus we evaluate the length and GC concentration of the regions, the nucleotide and haplotype variations and achieved phylogenetic and phylogeographic analyzes were madedinferences. To determine test the functionality of the sequences obtained we were searched and compared conserved motifs in spacer ITS1 and 5.8S gene and the haplotypes of spacer ITS2 was evaluated the ITS2 its secondary structure by transferability of helices in known secondary structures known of closely phylogenetically related species. Thus, the three regions showed polymorphisms represented by generating haplotypes for each region. Thise results suggest that the all different haplotypes present in U. gibba are functional copies that can should be used as phylogenetic markers for species studies, either alone each isolated or the complete ITS region (ITS1 + 5.8S + ITS2). But in phylogenetic and phylogeographical analyszes artifacts and erroneous evolutionary histories can be generated when populations from the same species were compared, in population studies due the presence of haplotypes shared by individuals from different populations. Hence, the present results show the need to analyze the variability of the ITS region before its use as a molecular marker.
The aquatic carnivorous plant, Utricularia gibba (Lentibulariaceae) has a small genome of with approximately 82 Mpb and was used in this work for the variance analysis of the copies diversity of the ribosomal DNA ITS region (nrDNA). One of the nrDNA features is that its its copies in tandem ys have present a high degree of similarity in intra individual and interspecies genomes due the homogenizing action of concerted evolution. However, in this study intragenomic, intra, and inter-populational variations were found in ITS1 + 5.8S + ITS2 ITS regions in individuals and populations evaluated. U. gibba. With the main objectiveaim of to elucidate the impact of polymorphisms of thein the intergenic spacers ITS1, ITS2, and gene 5.8S and ITS2 regions in phylogenetic and phylogeographic analyszes, we was cloned the complete ITS region of 25 individuals from 5 populations, thereby obtained 292 clones copies and internal spacers ITS1 and ITS2 and the 5.8S gene were identified, which were analyzed individually (ITS1, 5.8S, and ITS2) and togetherconcatenated. Thus we evaluate the length and GC concentration of the regions, the nucleotide and haplotype variations and achieved phylogenetic and phylogeographic analyzes were madedinferences. To determine test the functionality of the sequences obtained we were searched and compared conserved motifs in spacer ITS1 and 5.8S gene and the haplotypes of spacer ITS2 was evaluated the ITS2 its secondary structure by transferability of helices in known secondary structures known of closely phylogenetically related species. Thus, the three regions showed polymorphisms represented by generating haplotypes for each region. Thise results suggest that the all different haplotypes present in U. gibba are functional copies that can should be used as phylogenetic markers for species studies, either alone each isolated or the complete ITS region (ITS1 + 5.8S + ITS2). But in phylogenetic and phylogeographical analyszes artifacts and erroneous evolutionary histories can be generated when populations from the same species were compared, in population studies due the presence of haplotypes shared by individuals from different populations. Hence, the present results show the need to analyze the variability of the ITS region before its use as a molecular marker.
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Palavras-chave
Evolução em concerto, ITS motifs, Polimorfismos, nrDNA, Utricularia gibba, Concerted evolution, Polymorphisms