Brycon hilarii is a migratory fish widely distributed throughout the Paraguay River Basin. It is appreciated in sport fishing and for its superior meat quality. It is also the main species for tourist attraction in the Bonito region (State of Mato Grosso do Sul, Brazil). Considering the lack of information on the genetic structure of the fish of this species, the aim of the present study was to detect the genetic variability of Brycon hilarii through RAPD markers. A total of eighty specimens collected in different seasons at four sites of the Miranda River sub-basin (Paraguay River Basin, Brazil) were used for analysis. The results of genetic similarity, Shannon diversity, and AMOVA revealed differences between the sampling sites. Through AMOVA, differences between populations were more evident among the animals collected during the non-reproductive season, corresponding to a time of less movement of these fish. A population structuring model in which B. hilarii appears organized into genetically differentiated reproductive units that coexist and co-migrate through the studied system was suggested, contrasting the currently accepted idea that freshwater migratory fish form large panmictic populations in a determined hydrographic system. Despite the lack of a complete picture regarding the distribution of B. hilarii in the studied region, this initial idea on its population genetic structure could be an important contribution to providing aid for management and conservation programs of these fish.Keywords: Bryconinae, Characidae, conservation genetics, population genetics. Evidência genética de estruturação populacional do peixe neotropical de água doce Brycon hilarii ResumoBrycon hilarii é uma espécie de peixe migrador, distribuída por toda a Bacia do Paraguai, bastante apreciada tanto pela qualidade da carne quanto para a pesca esportiva, além de ser a principal espécie de interesse turístico da região de Bonito (MS, Brasil). Considerando a ausência de informações sobre a estrutura genética dos peixes desta espécie, o presente trabalho visou detectar a variabilidade genética de Brycon hilarii através de marcadores RAPD. Foi estudado um total de 80 exemplares amostrados em diferentes períodos do ano, em 4 localidades da sub-bacia do Rio Miranda (Bacia do Rio Paraguai, Brasil). Os resultados de similaridade genética, de diversidade de Shanon e AMOVA evidenciaram diferenças entre as localidades amostradas. Através da AMOVA, a diferenciação populacional foi mais evidente entre os peixes coletados no período não-reprodutivo, que representa a época de menor deslocamento desses peixes. Desta forma, ao contrário da idéia até então aceita de que os peixes migradores de água doce formam grandes populações panmíticas em um dado sistema hidrográfico, sugere-se a ocorrência de um modelo de sub-estruturação populacional onde os indivíduos de B. hilarii se organizam em unidades reprodutivas geneticamente diferenciadas e mantêm sua integridade co-existindo e co-migrando através do sistema estudado. Apesar da falta de u...
We describe seven microsatellite loci, including tetra-, tri-and dinucleotides, isolated from Brycon hilarii , which is a migratory fish inhabiting the Paraguay River basin (Brazil) and is highly valued for its meat quality. Three to eight alleles per locus were detected and the expected heterozygosity ranged from 0.31 to 0.81. Positive results were obtained with crossamplification in five other species of Brycon . These microsatellites provide a potential tool for wild population and aquaculture studies of B. hilarii and other species of the genus.
Human activities have a considerable impact on hydrographic systems and fish fauna. The present review on conservation genetics of neotropical freshwater fish reveals that DNA analyses have been promoting increased knowledge on the genetic structure of fish species and their response to environmental changes. This knowledge is fundamental to the management of wild fish populations and the establishment of Evolutionary Significant Units capable of conserving genetic integrity. While population structuring can occur even in long-distance migratory fish, isolated populations can show reduced genetic variation and be at greater risk of extinction. Phylogeography and phylogeny have been powerful tools in understanding the evolution of fish populations, species and communities in distinct neotropic environments. Captive fish can be used to introduce new individuals and genes into the wild and their benefits and disadvantages can be monitored through genetic analysis. Understanding how fish biodiversity in neotropical freshwaters is generated and maintained is highly important, as these habitats are transformed by human development and fish communities are increasingly exploited as food sources to sustain a growing human population.Keywords: molecular genetics, fish population, biology conservation. Contribuição da Genética da Conservação para o conhecimento da biodiversidade dos peixes de água doce neotropicais ResumoAtividades humanas têm um grande impacto sobre os sistemas hidrográficos e a fauna de peixes. A presente revisão em genética da conservação dos peixes de água doce neotropicais revela que as análises de DNA têm promovido um crescimento no conhecimento da estrutura genética das espécies e suas respostas às alterações ambientais. Este conhecimento é fundamental para o manejo das populações de peixes nativos e para o estabelecimento de Unidades Evolutivas Significantes capazes de conservar a integridade genética dessas populações. Enquanto o fenômeno de estruturação de populações pode ocorrer mesmo em peixes migradores de longas distâncias, populações isoladas podem mostrar reduzida variação genética e apresentar grande risco de extinção. Em adição, a filogeografia e a filogenia têm dado importantes contribuições para o entendimento da evolução das populações, espécies e comunidades de peixes em distintos ambientes neotropicais. Populações de cativeiro podem ser utilizadas como fonte de introdução de novos indivíduos e genes no ambiente natural e seus benefícios e desvantagens podem ser monitorados por meio de análises genéticas. É altamente importante, portanto, entender como é gerada e mantida a biodiversidade de peixes de água doce neotropicais, uma vez que os habitats são transformados pelo desenvolvimento humano e as comunidades de peixes têm sido intensamente exploradas como alimento de sustentação desse crescimento das populações humanas.Palavras-chave: genética molecular, populações de peixes, conservação biológica.
ABSTRACT. Previous genetic studies conducted with migratory fish populations from downstream of the Três Marias dam in the São Francisco River Basin (Brazil) have documented the occurrence of population structuring, as reported for Brycon orthotaenia and Prochilodus argenteus, two commercially important species in this basin. We revisited the genetic structure of these species using microsatellites. B. orthotaenia was sampled during the spawning season and was analyzed using five heterologous microsatellites. P. argenteus was collected in the non-reproductive season and genetic analysis was conducted using ten speciesspecific microsatellites. For both species, genetic diversity between collection sites was similar. Considering B. orthotaenia, F ST and R ST estimates and the Bayesian analysis demonstrated significant differences between sites. Two well-defined populations were identified in the study area, indicating population structuring for this species. No significant differences were found for P. argenteus. These data provide information for knowledge regarding genetic structure of migratory fish species, which may contribute toward the conservation besides the understanding the biology and ecology of these important fishery resources. Keywords: migratory fish, freshwater fish, genetic structure, Characidae, Prochilodontidae, microsatallite, Brazil.Estructura genética poblacional de dos especies de peces migratorios de agua dulce (Brycon orthotaenia y Prochilodus argenteus) en la cuenca del Río San Francisco (Brasil) y su importancia para la conservación RESUMEN. Estudios genéticos anteriores realizados con poblaciones de peces migratorios de aguas abajo de la represa de las Tres Marías en la cuenca del río San Francisco (Brasil) han documentado casos de estructuración genética, como se ha descrito para Brycon orthotaenia y Prochilodus argenteus, dos especies de importancia comercial. Se revisó la estructura genética de estas especies utilizando microsatélites. Se obtuvieron muestras de B. orthotaenia durante la temporada de desove y se analizaron mediante cinco microsatélites heterólogos. Muestras de P. argenteus fueron recogidas en la temporada no reproductiva y el análisis genético se realizó utilizando diez microsatélites específicos para P. argenteus. Para ambas especies, la diversidad genética entre los sitios de recolección fue similar. Considerando a B. orthotaenia, las estimaciones F ST y R ST y el análisis Bayesiano demostraron diferencias significativas entre los sitios. Se identificaron dos poblaciones bien definidas en el área de estudio, indicando una estructuración de la población de esta especie. No se encontraron diferencias significativas para P. argenteus. Estos datos proporcionan información para el conocimiento sobre la estructura genética de las especies de peces migratorios, que puede contribuir a la conservación, además de la comprensión de la biología y ecología de estos importantes recursos pesqueros. Palabras clave: peces migratorios, peces de agua dulce, estructura genética, Chara...
DNA molecular analyses were used in a forensic investigation involving illegal wildlife poaching in central Brazil. The Brazilian environmental agency (IBAMA) sent us two samples of confiscated meat from illegal poaching for species and individual identification. Comparative analysis of cytochrome b sequences (1,070 bp) provided incontestable evidence that the meat samples were from the lowland tapir, Tapirus terrestris. The analysis of nine microsatellites indicated that the two seized meat samples shared the same genotypes, implying that meat from only one individual was present. The lowland tapir is the last representative of megamammals in South America and is a vulnerable species, locally extinct in several regions. The present paper reports a successful genetic investigation of an illegal hunting crime, in which DNA-based molecular analyses of seized ground meat samples were the only tool able to identify the species and individual, proving to be highly useful for wildlife crime investigations.
BackgroundIllegal hunting is one of the major threats to vertebrate populations in tropical regions. This unsustainable practice has serious consequences not only for the target populations, but also for the dynamics and structure of tropical ecosystems. Generally, in cases of suspected illegal hunting, the only evidence available is pieces of meat, skin or bone. In these cases, species identification can only be reliably determined using molecular technologies. Here, we reported an investigative study of three cases of suspected wildlife poaching in which molecular biology techniques were employed to identify the hunted species from remains of meat.FindingsBy applying cytochrome b (cyt-b) and cytochrome oxidase subunit I (COI) molecular markers, the suspected illegal poaching was confirmed by the identification of three wild species, capybara (Hydrochoerus hydrochaeris), Chaco Chachalaca (Ortalis canicollis) and Pampas deer (Ozotoceros bezoarticus). In Brazil, hunting is a criminal offense, and based on this evidence, the defendants were found guilty and punished with fines; they may still be sentenced to prison for a period of 6 to 12 months.ConclusionsThe genetic analysis used in this investigative study was suitable to diagnose the species killed and solve these criminal investigations. Molecular forensic techniques can therefore provide an important tool that enables local law enforcement agencies to apprehend illegal poachers.
White-lipped peccaries, Tayassu pecari, are neotropical ungulates whose populations have been declining in numerous locations within their geographical distribution. Here we describe 16 microsatellite loci isolated from T. pecari and their cross-amplification in collared peccaries, Pecari tajacu. In 30 individuals of T. pecari, a total of 32 alleles were found in ten polymorphic loci, ranging from 2 to 8 alleles per locus with a mean of 3.2. The expected and observed heterozygosity ranged from 0.143 to 0.802 and from 0 to 0.704, respectively. Two loci deviated from Hardy-Weinberg equilibrium. In P. tajacu, nine loci were polymorphic with a mean of 3.2 alleles per locus. These molecular markers will be useful to study the genetic status of peccary populations and, consequently, to help their conservation.
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