RESUMO
Due to the ecological importance of Lophiosilurus alexandri, the present work evaluated its genetic representativeness by comparing wild stocks to broodstocks that were kept at three restocking hatcheries along the São Francisco River. A total of 97 samples were genotyped for newly developed microsatellite markers. Low levels of genetic diversity (average alleles number of 4.2 alleles) were detected in all cases, being more severe in captive groups. Significant pairwise FST and DEST values, Structure, and DAPC analyses showed that wild animals were structured in two groups, and a third group was formed by captive animals, evidencing the need to adopt genetic criteria to retain genetic diversity in the hatcheries. For this reason, three full-sib families were constructed to select the best relatedness estimator for L. alexandri and establish a cut-off value aimed to avoid full-sibling matings in the hatcheries. Two estimators, Wang (RW) and Lynch & Li (RLL), were accurate in reflecting the relatedness level for full-sibs in this species. According to them, less than 50% of the potential breeding matings in the three hatcheries are advisable. The innate low diversity of L. alexandri highlights the importance of minimizing inbreeding and retaining genetic diversity towards the species recovery.(AU)
Devido à importância ecológica de Lophiosilurus alexandri, o presente trabalho avaliou sua representatividade genética, comparando estoques selvagens com plantéis de reprodutores de três larviculturas ao longo do Rio São Francisco. Noventa e sete amostras foram genotipadas com marcadores microssatélites recém-desenvolvidos. Baixos níveis de diversidade genética (número médio de alelos de 4,2) foram detectados em todos os casos, sendo mais severo no cativeiro. Os valores de FST e DEST par a par, as análises do Structure e DAPC mostraram a estruturação dos animais selvagens em dois grupos, e um terceiro formado pelas larviculturas, evidenciando a necessidade de adoção de critérios genéticos para retenção da diversidade genética no cativeiro. Por essa razão, três famílias de irmãos completos foram construídas para selecionar o melhor estimador de parentesco para a espécie e estabelecer os valores mínimos de corte para evitar cruzamentos indesejados. Dois estimadores, Wang (RW) e Lynch & Li (RLL), foram eficientes em refletir as relações de parentesco para irmãos completos nessa espécie. Segundo eles, menos de 50% dos potenciais cruzamentos são recomendáveis nas três larviculturas. A baixa diversidade genética inerente ao L. alexandri destaca a importância de minimizar a consanguinidade e evitar perda de diversidade genética, visando a recuperação da espécie.(AU)
Assuntos
Animais , Variação Genética , Peixes-Gato/genética , Aquicultura , CruzamentoRESUMO
This article documents the addition of 153 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Brassica oleracea, Brycon amazonicus, Dimorphandra wilsonii, Eupallasella percnurus, Helleborus foetidus, Ipomoea purpurea, Phrynops geoffroanus, Prochilodus argenteus, Pyura sp., Sylvia atricapilla, Teratosphaeria suttonii, Trialeurodes vaporariorum and Trypanosoma brucei. These loci were cross-tested on the following species: Dimorphandra coccicinea, Dimorphandra cuprea, Dimorphandra gardneriana, Dimorphandra jorgei, Dimorphandra macrostachya, Dimorphandra mollis, Dimorphandra parviflora and Dimorphandra pennigera.
Assuntos
Ascomicetos/genética , Bases de Dados Genéticas , Dípteros/genética , Plantas/genética , Trypanosoma brucei brucei/genética , Animais , Ecologia , Repetições de Microssatélites , Dados de Sequência MolecularRESUMO
The genetic variability of Entamoeba dispar strains was investigated in 39 positive isolates on a survey of 1783 individuals from two different cities of Northeast Brazil (Recife and Macaparana) using two polymorphic species-specific loci (loci 1-2 and 5-6). A combinatory clustering analysis revealed no geographical correlation and remarkable genetic polymorphism among all the isolates examined. Nevertheless, a comparison of the frequency of eight individual PCR products, shared by both Recife and Macaparana populations, for the two loci, showed that only one product of locus 5-6 was significantly different between the two cities. These results suggested that the Macaparana population is infected by similar strains and that locus 5-6 shows potential in assaying questions related to the molecular epidemiology of this region.
Assuntos
Disenteria Amebiana/parasitologia , Entamoeba/genética , Enteropatias Parasitárias/parasitologia , Adolescente , Animais , Brasil/epidemiologia , Criança , Pré-Escolar , Análise por Conglomerados , DNA de Protozoário/química , DNA de Protozoário/genética , Disenteria Amebiana/epidemiologia , Entamoeba/isolamento & purificação , Fezes/parasitologia , Variação Genética , Humanos , Enteropatias Parasitárias/epidemiologia , Reação em Cadeia da Polimerase , Áreas de Pobreza , População Rural , População UrbanaRESUMO
Previous studies using methods varying from traditional serologic tests to molecular biology techniques have shown that in northeastern Brazil, Entamoeba dispar was more prevalent than E. histolytica. In this study, the prevalence was established by using E. histolytica stool antigen detection kits and a polymerase chain reaction (PCR) with genomic DNA extracted from cultured trophozoites in all four-nuclei, amoeba-positive samples from a population living in Macaparana in northeastern Brazil. Among 1,437 stool samples analyzed, only 59 (4.1%) were positive for four nuclei amoeba. However, all of these samples were negative in an immunoenzymatic assay for the presence of E. histolytica-specific galactose adhesin. Of 59 cultivated samples, only 31 showed trophozoites. Extraction of DNA from these 31 samples, followed by the PCR, showed that 23 samples (74.19%) were positive for E. dispar and no amplification was observed for pathogenic E. histolytica. The remaining eight samples were negative for both species. These findings are consistent with those previously reported.
