RESUMEN
The genetic relationships of native or introduced Plagioscion squamosissimus in five Brazilian Neotropical basins were evaluated using the mitochondrial atpase6/8 genes. Results revealed that the population of the Tocantins River basin is more basal than the native populations of the Amazon and Parnaíba River basins. Moreover, the populations of P. squamosissimus that were introduced in the São Francisco and upper Paraná River basins originated from the population of the Parnaíba River.
Asunto(s)
Peces/clasificación , Peces/genética , Genes Mitocondriales/genética , ATPasas de Translocación de Protón Mitocondriales/genética , Animales , Secuencia de Bases , Brasil , ADN Mitocondrial/química , ADN Mitocondrial/aislamiento & purificación , Variación Genética , Haplotipos , Especies Introducidas , Funciones de Verosimilitud , Filogenia , Dinámica Poblacional , RíosRESUMEN
The genetic diversity of invasive and native populations of Plagioscion squamosissimus (Heckel, 1840) from the Paraná, Parnaiba and Araguaia-Tocantins river basins was assessed by using Random Amplified Polymorphic DNA (RAPD) markers. Genetic data confirmed the hypothesis of low genetic variability within and among P. squamosissimus populations introduced in the upper Paraná River basin, and indicated that they likely originated from a common ancestor. Moreover, the data demonstrated that, in agreement with available historical records, the P. squamosissimus populations established in the Paraná River basin were derived from a population native to the Parnaíba River basin. The genetic data presented here are of potential future application for the management of the invasive P. squamosissimus populations and for the preservation of the genetic legacy of native fish.
Asunto(s)
Especies Introducidas , Perciformes/genética , Animales , Brasil , Variación Genética , Genética de Población , Técnica del ADN Polimorfo Amplificado Aleatorio , RíosRESUMEN
The genetic divergence among invasive and native populations of Plagioscion squamosissimus from four Neotropical hydrographic basins was assessed using the hypervariable domain of the mitochondrial DNA (mtDNA) control region. Plagioscion squamosissimus is native to the neighbouring hydrographic basins of the Parnaíba and Amazon Rivers, and the latter includes the Araguaia-Tocantins drainage, but it is invasive in other basins due to introductions. The mtDNA nucleotide polymorphism supported the hypothesis that the Amazon and Parnaíba populations constitute the same species and are separated into two independent evolutionary lineages. Absence of nucleotide polymorphism was observed within and among P. squamosissimus populations invasive to the uppper and middle Paraná River basins. Nucleotide divergence was null or low comparing the Paraná invasive populations with the populations native to the Parnaíba River basin, whereas it was significantly high compared to Tocantins populations. These results ascertain that P. squamosissimus populations invasive to the upper Paraná River basin and to the middle Paraná River basin downstream of the Itaipu dam are derived from the Parnaíba River basin. The genetic data presented are potentially useful to assist further studies on P. squamosissimus taxonomic and geographic distribution, development of ecological guidelines for managing populations invasive to the upper Paraná River basin and for preservation of native fish diversity.
Asunto(s)
Variación Genética , Especies Introducidas , Perciformes/genética , Animales , ADN Mitocondrial/genética , Flujo Genético , Haplotipos , Perciformes/clasificación , Filogenia , Ríos , América del Sur , Clima TropicalRESUMEN
The morphological discrimination between the species Astyanax altiparanae and A. asuncionensis of the upper Paraná River and Paraguay River basins, respectively, has always been difficult. Two D-loop haplogroups of A. altiparanae are known, one with the presence (AltoPR) or the absence (AltoPR-D) of a 32-bp block similar to that in A. asuncionensis. We examined these samples to characterize A. altiparanae and verify whether A. asuncionensis occurred in the upper Paraná River prior to the submergence of the Sete Quedas Falls when Itaipu reservoir was impounded. D-loop sequences were analyzed in A. altiparanae of the upper Paraná and Iguaçu Rivers and those of A. asuncionensis of the upper Paraguay River. The haplogroup AltoPR was found at all sites of the upper Paraná and Iguaçu Rivers, whereas AltoPR-D occurred in the Itaipu reservoir, floodplain and in the Tietê and Grande Rivers. Two haplogroups of A. asuncionensis were identified and both did not have the 32-bp block. However, AltoPR and AltoPR-D differed from one another in 5.1% of their bases and between 8.9 and 12.5% with regard to the haplogroups of the upper Paraguay basin. Further, AltoPR-D occurred in the Grande River upstream the Marimbondo Falls and other older reservoirs than Itaipu. The results reject the hypothesis of the establishment of A. asuncionensis and suggest that the haplogroup AltoPR-D existed in the upper Paraná River before the impounding of the Itaipu reservoir. Moreover, morphological similarity and high genetic variation within the altiparanae/asuncionensis group suggest the existence of a cryptic species complex.
Asunto(s)
Characidae/genética , ADN Mitocondrial/genética , Animales , Secuencia de Bases , Brasil , Cartilla de ADN , Evolución Molecular , Haplotipos , Datos de Secuencia Molecular , Polimorfismo Genético , Homología de Secuencia de Ácido NucleicoRESUMEN
Brycon is one of the main genera of Neotropical freshwater fish. In Brazil, Brycon species have been found in many hydrographic basins, such as the Amazon, Paraná, Paraguay, and Araguaia-Tocantins basins. We examined the phylogenetic relationships among the species Brycon orbignyanus, B. hilarii, B. cf. pesu, B. cephalus, B. falcatus, and B. gouldingi, using mitochondrial and nuclear molecular markers. Specimens of B. orbignyanus were collected in the Paraná River. Specimens of B. hilarii were collected in the Manso River. Specimens of B. cephalus were obtained from a fish farm, and specimens of B. cf. pesu, B. falcatus and B. gouldingi were sampled in the Araguaia-Tocantins basin. DNA extraction was carried out using the phenol/chloroform method. Molecular polymorphism studies of Brycon species were carried out with the inter-simple sequence repeat (ISSR) technique, using the total DNA of six specimens of each species. In DNA amplification of B. cf. pesu, eight specimens were used. The partial sequence of mitochondrial cytochrome b was amplified by PCR. The PCR products were used directly in sequencing reactions. Each ISSR primer produced from 7 to 14 scorable and reproducible bands. The (GGAC)(3)A and (GGAC)(3)C primers produced the greatest number of species-specific bands. A 264-bp fragment, corresponding to the partial region of mitochondrial DNA cytochrome b, was sequenced and used for analysis. According to the phylogenetic tree obtained from the data, these Brycon species can be divided into two clades: one comprised only B. cf. pesu, and the second comprised the remaining Brycon species. We conclude that ISSR primers can be used for the identification of species-specific bands in fish, such as Brycon spp.
Asunto(s)
Ecosistema , Peces/genética , Agua Dulce , Filogenia , Animales , Secuencia de Bases , Brasil , Citocromos b/genética , ADN Mitocondrial/genética , Electroforesis en Gel de Agar , Geografía , Repeticiones de Minisatélite/genética , Datos de Secuencia Molecular , Análisis de Componente Principal , Especificidad de la EspecieRESUMEN
Pseudoplatystoma corruscans (Spix and Agassiz, 1829) and Pseudoplatystoma reticulatum (Eingenmann and Eigenmann, 1889) are large migratory catfishes of high biological importance and great commercial value in South America. Because fertile crossbreeds can be artificially produced in hatcheries, a high genetic proximity between these two Pimelodidae species is conceivable. Possible escape of crossbred specimens from pisciculture stations is a serious environmental concern. Despite their importance, knowledge of P. corruscans and P. reticulatum biology, ecology, population diversity and genetics is limited. In the present work, the genetic divergence between P. corruscans and P. reticulatum populations from the Paraná River Basin was analyzed on the basis of polymorphisms in ISSR fragments and in the hypervariable sequence of the mitochondrial DNA (mtDNA) control region. Estimates of intraspecific haplotype (h > 0.5) and nucleotide diversities (pi < 0.01) indicate that P. corruscans and P. reticulatum have survived a historical population decline, followed by a demographic expansion. The interspecific polymorphisms within the mtDNA control region and ISSR fragments were suitable as diagnostic molecular markers and could be used to discriminate the two species. A unique Pseudoplatystoma specimen, captured in the Upper Paraná River Floodplain, was identified by these DNA diagnostic markers as a hybrid P. reticulatum x P. corruscans, which possibly escaped from pisciculture. The integrity of the natural population of P. corruscans in the Upper Paraná River is at risk of genetic introgression or homogenization due to the presence of hybrids and the transposition of P. reticulatum upstream through the Canal da Piracema at Itaipu Dam. Data presented herein improve the understanding of the genetic relatedness between P. corruscans and P. reticulatum and represent potential tools for future programs of conservation and surveillance of genetic introgression events and the genetic integrity of these populations.
Asunto(s)
Bagres/genética , ADN Mitocondrial/genética , Animales , Genética de Población , Reacción en Cadena de la Polimerasa , Polimorfismo Genético/genética , RíosRESUMEN
Pseudoplatystoma corruscans (Spix and Agassiz, 1829) and Pseudoplatystoma reticulatum (Eingenmann and Eigenmann, 1889) are large migratory catfishes of high biological importance and great commercial value in South America. Because fertile crossbreeds can be artificially produced in hatcheries, a high genetic proximity between these two Pimelodidae species is conceivable. Possible escape of crossbred specimens from pisciculture stations is a serious environmental concern. Despite their importance, knowledge of P. corruscans and P. reticulatum biology, ecology, population diversity and genetics is limited. In the present work, the genetic divergence between P. corruscans and P. reticulatum populations from the Paraná River Basin was analyzed on the basis of polymorphisms in ISSR fragments and in the hypervariable sequence of the mitochondrial DNA (mtDNA) control region. Estimates of intraspecific haplotype (h > 0.5) and nucleotide diversities (π < 0.01) indicate that P. corruscans and P. reticulatum have survived a historical population decline, followed by a demographic expansion. The interspecific polymorphisms within the mtDNA control region and ISSR fragments were suitable as diagnostic molecular markers and could be used to discriminate the two species. A unique Pseudoplatystoma specimen, captured in the Upper Paraná River Floodplain, was identified by these DNA diagnostic markers as a hybrid P. reticulatum x P. corruscans, which possibly escaped from pisciculture. The integrity of the natural population of P. corruscans in the Upper Paraná River is at risk of genetic introgression or homogenization due to the presence of hybrids and the transposition of P. reticulatum upstream through the Canal da Piracema at Itaipu Dam. Data presented herein improve the understanding of the genetic relatedness between P. corruscans and P. reticulatum and represent potential tools for future programs of conservation and surveillance of genetic ...
Pseudoplatystoma corruscans Spix e Agassiz, 1829 e Pseudoplatystoma reticulatum Eigenmann e Eigenmann, 1889 são peixes migratórios de grande porte, com alta importância biológica e elevado valor comercial na América do Sul. Híbridos férteis são obtidos em cativeiro e, portanto, é esperada alta proximidade genética entre essas duas espécies de Pimelodidae. Escapes de espécimes híbridos a partir de estações de piscicultura representam um sério problema ambiental. Apesar da sua importância, conhecimentos sobre a biologia, ecologia, diversidade de populações e genética de P. corruscans e P. reticulatum são escassos. No presente trabalho, foi avaliada a divergência genética entre P. corruscans e P. reticulatum da Bacia do Rio Paraná, com base em fragmentos ISSR e na seqüência D-loop do DNA mitocondrial (mtDNA). As estimativas das diversidades intra-específicas haplotípica (h > 0,5) e nucleotídica (π < 0,01) evidenciaram que P. corruscans e P. reticulatum sobreviveram a um declínio populacional histórico, seguido de expansão demográfica. Os polimorfismos interespecíficos no mtDNA e nos fragmentos ISSR foram eficientes para diagnósticos e discriminaram as duas espécies. Um espécime de Pseudoplatystoma capturado na planície de inundação do Alto Rio Paraná foi identificado com esses marcadores moleculares como híbrido P. reticulatum x P. corruscans, que possivelmente escapou de psicicultura. A integridade da população de P. corruscans no Alto Rio Paraná está ameaçada, por introgressão ou homogeneização genética, pela presença de híbridos e pela transposição para montante de P. reticulatum através do Canal da Piracema em Itaipu. Os dados apresentados constituem um avanço na compreensão do parentesco entre P. corruscans e P. reticulatum e representam ferramentas em potencial para programas de conservação biológica, incluindo o monitoramento de introgressão e de integridade genética das populações.
Asunto(s)
Animales , Bagres/genética , ADN Mitocondrial/genética , Genética de Población , Reacción en Cadena de la Polimerasa , Polimorfismo Genético/genética , RíosRESUMEN
Brycon pesu is a small-sized fish distributed throughout the Amazon and Orinoco Basins and other coastal basins of northeastern South America. Brycon cf. pesu specimens from the Araguaia-Tocantins Basin are currently separated into two morphotypes, Brycon sp1 and Brycon sp2, owing to different coloration of their anal fin. Brycon sp2 has a reddish margin stripe on the anal fin which morphologically distinguishes it from Brycon sp1. In the present research, nuclear and mitochondrial markers were used to test the hypothesis that the Brycon sp1 and Brycon sp2 morphotypes are distinct species. Specimens from the two morphotypes were collected from the Lajeado Hydroelectric Plant and the Palmas River in the Araguaia-Tocantins Basin. Thirty-five loci obtained by the amplification of five inter-simple sequence repeat primers were analyzed but no species-specific bands were detected. Electrophoretic profiles obtained from 5S rDNA non-transcribed spacer amplification failed to show any differentiation in morphotypes. These results were corroborated by nucleotide sequence analysis of the mtDNA control region, in which 24 polymorphic nucleotide sites, representing a polymorphism rate of only 5%, were detected. The low rates of polymorphism detected by inter-simple sequence repeat, non-transcribed spacer and mtDNA D-loop markers strongly reject the hypothesis that the two morphotypes Brycon sp1 and Brycon sp2 represent distinct species within Brycon cf. pesu. Further studies are needed to obtain conclusive data on the notion that the coloration of the anal fin is an intraspecific polymorphism, possibly related to environmental factors.
Asunto(s)
ADN Intergénico/genética , ADN Mitocondrial/genética , Peces/genética , Variación Genética , ARN Ribosómico 5S/genética , Animales , Secuencia de Bases , Brasil , ADN/genética , ADN/aislamiento & purificación , Peces/clasificación , Marcadores Genéticos , Genoma , Geografía , Repeticiones de Microsatélite , Conformación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Análisis de Secuencia de ADN , Especificidad de la EspecieRESUMEN
Brycon pesu is a small-sized fish distributed throughout the Amazon and Orinoco Basins and other coastal basins of northeastern South America. Brycon cf. pesu specimens from the Araguaia-Tocantins Basin are currently separated into two morphotypes, Brycon sp1 and Brycon sp2, owing to different coloration of their anal fin. Brycon sp2 has a reddish margin stripe on the anal fin which morphologically distinguishes it from Brycon sp1. In the present research, nuclear and mitochondrial markers were used to test the hypothesis that the Brycon sp1 and Brycon sp2 morphotypes are distinct species. Specimens from the two morphotypes were collected from the Lajeado Hydroelectric Plant and the Palmas River in the Araguaia-Tocantins Basin. Thirty-five loci obtained by the amplification of five inter-simple sequence repeat primers were analyzed but no species-specific bands were detected. Electrophoretic profiles obtained from 5S rDNA non-transcribed spacer amplification failed to show any differentiation in morphotypes. These results were corroborated by nucleotide sequence analysis of the mtDNA control region, in which 24 polymorphic nucleotide sites, representing a polymorphism rate of only 5%, were detected. The low rates of polymorphism detected by inter-simple sequence repeat, non-transcribed spacer and mtDNA D-loop markers strongly reject the hypothesis that the two morphotypes Brycon sp1 and Brycon sp2 represent distinct species within Brycon cf. pesu. Further studies are needed to obtain conclusive data on the notion that the coloration of the anal fin is an intraspecific polymorphism, possibly related to environmental factors.
Asunto(s)
Animales , ADN Intergénico/genética , ADN Mitocondrial/genética , Variación Genética , Peces/genética , /genética , Secuencia de Bases , Brasil , ADN , Marcadores Genéticos , Genoma , Geografía , Repeticiones de Microsatélite , Conformación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Peces/clasificación , Análisis de Secuencia de ADN , Especificidad de la EspecieRESUMEN
We have shown that the open reading frame orf221 is an active mitochondrial gene which encodes a novel mitochondrial polypeptide. The orf221 sequence is common to higher plants but absent in animal and fungal mitochondria. A mitochondrial polypeptide with an apparent molecular weight of 21,000 was detected with a polyclonal antibody raised against an ORF221 fusion protein. In organello translation followed by immunoprecipitation with the anti-ORF221 antibody demonstrated that this polypeptide is encoded by the orf221 gene in plant mitochondria. The ORF221 was found to be a mitochondrial membrane protein in normal (N), cms-T, and cms-C cytoplasms of several inbred lines of maize (Zea mays L.) and in other plant species.