Análise filogenética de Brachyplatytoma platynemum (Siluriformes: Pimelodidae)
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Data
2012-02-23
Autores
Orrego, Luz Eneida Ochoa [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Brachyplatystoma platynemum é uma espécie de bagre amplamente distribuída no eixo Amazonas/Solimões e muitos de seus tributários e, apesar de ser considerado de baixo valor comercial, o declive do estoque de outras espécies de grandes bagres de interesse comercial tem levado ao incremento na captura desta espécie. Por outro lado, o estado atual da estrutura e variabilidade genética das populações desta espécie são desconhecidos. Neste sentido foi realizada uma análise filogeográfica através do sequenciamento de dois genes do DNA mitocondrial (região controle e o gene citocromo b) e de marcadores nucleares microssatélites, com o objetivo de determinar se a espécie esta composta de um único estoque geneticamente homogêneo ou se existe algum tipo de segregação genética associada com o espaço e o tempo, que possa ser relacionada com o comportamento de homing. Foi analisado um total de 216 indivíduos para a região controle, 140 para o gene citocromo b e 169 para seis locus microssatélites, em sete localidades. Os resultados indicam altos níveis de diversidade haplotípica e evidenciam estrutura genética dos indivíduos desta espécie em duas populações: rio Madeira e demais pontos de coleta, no entanto, a estrutura observada não constitui suficiente evidencia para ser associada ao comportamento de homing. Estimativas do tempo de divergência baseadas no mtDNA indicam que as populações divergiram entre 1,0 a 1,5 Ma, tempo durante o qual a influencia das mudanças climáticas podem ter contribuído para a estrutura atual das populações de B. platynemum. Embora o padrão filogeográfico concorde com as predições da hipótese dos refúgios do Pleistoceno, a influência de eventos paleogeográficos e hidrológicos não pode ser descartada. Nossos resultados mostram a interação das mudanças...
Brachyplatystoma platynemum is a catfish species widely distributed in the Amazonas / Solimões basin, despite being considered of little commercial interest, the decline of fish stock of other species has contributed to the increase in the catch of this species. However, the current state of the structure and genetic variability of populations of this species are unknown. In this sense a phylogeographic analysis was performed through sequencing of two mitochondrial molecular markers (control region and cytochrome b gene) and nuclear microsatellites. In order to determine whether the species is composed of a single genetic unit, or if there is any genetic segregation associated with space and time, which may be related to homing behavior. It was analyzed a total of 216 individuals in the control region, 140 for the gene cytochrome b and 169 individuals for six microsatellite loci in seven locations in the Amazon/Solimões basin. The results show high levels of haplotype diversity and evidence genetic structure in two populations (Amazon river channel and the Madeira River). However, the observed structure is not indicated of homing behavior. Divergence time estimates based on mtDNA indicated that the populations diverged between 1.5 to 1.0 Ma, during this time the influence of climate change may have contributed to the current structure of populations of B. platynemum. Although the phylogeographic patterns is consistent with the hypothesis of Pleistocene refuges, the influence of paleogeographic and hydrological events as a result of geological process in the Plio-Pleistocene, are important in the diversification of populations. Our results show the interaction of climate change as a result of hydrological and geological processes in the Plio-Pleistocene in the diversification of fish populations in the Amazon region. Finally... (Complete abstract click electronic access below)
Brachyplatystoma platynemum is a catfish species widely distributed in the Amazonas / Solimões basin, despite being considered of little commercial interest, the decline of fish stock of other species has contributed to the increase in the catch of this species. However, the current state of the structure and genetic variability of populations of this species are unknown. In this sense a phylogeographic analysis was performed through sequencing of two mitochondrial molecular markers (control region and cytochrome b gene) and nuclear microsatellites. In order to determine whether the species is composed of a single genetic unit, or if there is any genetic segregation associated with space and time, which may be related to homing behavior. It was analyzed a total of 216 individuals in the control region, 140 for the gene cytochrome b and 169 individuals for six microsatellite loci in seven locations in the Amazon/Solimões basin. The results show high levels of haplotype diversity and evidence genetic structure in two populations (Amazon river channel and the Madeira River). However, the observed structure is not indicated of homing behavior. Divergence time estimates based on mtDNA indicated that the populations diverged between 1.5 to 1.0 Ma, during this time the influence of climate change may have contributed to the current structure of populations of B. platynemum. Although the phylogeographic patterns is consistent with the hypothesis of Pleistocene refuges, the influence of paleogeographic and hydrological events as a result of geological process in the Plio-Pleistocene, are important in the diversification of populations. Our results show the interaction of climate change as a result of hydrological and geological processes in the Plio-Pleistocene in the diversification of fish populations in the Amazon region. Finally... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Bagre (Peixe) - Distribuição geográfica, Filogeografia, Mitocondria, Phylogeography
Como citar
ORREGO, Luz Eneida Ochoa. Análise filogenética de Brachyplatytoma platynemum (Siluriformes: Pimelodidae). 2012. 75 f. Dissertação (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Biociências de Botucatu, 2012.