RESUMEN
The success of recovery programs on degraded areas is dependent on the genetic material to be used, which should present heterozygosity and genetic diversity in native and recovered populations. This study was carried out to evaluate the model efficiency to enable the recovery of a degraded area of the Lower São Francisco, Sergipe, Brazil. The target species for this study was Schinus terebinthifolius Raddi. Three populations were analyzed, the recovered area, seed-tree source population, and native tree population border established to the recovered area. The random amplified polymorphic DNA (RAPD) markers were used for diversity analysis. Genetic structure was estimated to evaluate the level of genetic variability existent in each population. There was no correlation between the spatial distribution and the genetic distances for all trees of the recovered area. The heterozygosity present in the recovered population was higher than the native tree population. The seed-tree source population presents genetic bottlenecks. Three clusters were suggested (ΔK = 3) with non-genetic structure. High intra-population genetic variability and inter-population differentiation are present. However, gene flow may also introduce potentially adaptive alleles in the populations of the recovered area, and the native population is necessary to ensure the sustainability and maintenance of the populations by allelic exchange.
Asunto(s)
Anacardiaceae/genética , Especies en Peligro de Extinción , Adaptación Fisiológica , Alelos , Anacardiaceae/crecimiento & desarrollo , Flujo Génico , Genotipo , Heterocigoto , Polimorfismo Genético , Semillas/genéticaRESUMEN
The goal of this study was to characterize the structure of two natural populations of the coral tree using RAPD and ISSR markers. The study evaluated all individuals in two different areas in the northeastern region of Brazil: the first was in the riparian area, 10 km x 100 m along the edge of the lower São Francisco River, and the second was in the municipality of Pinhão, in a semiarid region between the municipalities of Neópolis and Santana do São Francisco. We used all the coral trees present in those two areas (37 individuals). The results of the RAPD and ISSR markers were highly congruent, supporting the reliability of the techniques used. Similarity was estimated using the Jaccard arithmetic complement index. A dendrogram was constructed using the unweighted pair group method with arithmetic mean cluster algorithm, and the robustness of the data was bootstrapped with 5000 replicates. A principal coordinate analysis was performed on the basis of Jaccard coefficients. The total genetic variation observed was 21%, corresponding to the variation between the populations, and 79% of the variation was observed within the populations.
Asunto(s)
Erythrina/genética , Extinción Biológica , Genética de Población , Sitios Genéticos , Variación Genética , Filogenia , Análisis de Componente PrincipalRESUMEN
O sistema experimental utilizado na realizaçäo do teste de lavagem de nitrogênio com respiraçäo única (TN2-RU) compöe-se de vários dispositivos destinados à obtençäo de mediçöes confiáveis de fluxos e volumes respirados. Neste trabalho é apresentado um sistema experimental alternativo baseado em computador que dispensa equipamentos adicionais por possibilitar a correçäo dos erros pelo programa de processamento do teste, utilizando equaçöes que descrevem algums dos erros e determinaçöes experimentais prévias de outros. As mediçöes de fluxo aéreo e fraçöes de N2 säo feitas, respectivamente, com pneumotacógrafo e analisador rápido de gases. Na análise dos erros com origem no pneumotacógrafo considera-se a diferença entre as geometrias do sistema de conduçäo de ar a montante e a jusante do local de mediçäo e as variaçöes na viscosidade do ar respirado durante o teste, propondo-se um algoritmo para correçäo destas variaçöes que utiliza apenas as fraçöes de N2 medidas. Para o analisador de N2, determina-se experimentalmente causas de atrasos entre equipamentos: espaço morto do sistema e tempo de resposta do aparelho. A avaliaçäo do algoritmo para correçäo das variaçöes da viscosidade feita por modelo matemático de trocas gasosas mostra erros inferiores a 0,4% para pulmöes unicompartimentais. Conclui-se pela validade do sistema baseado em computador para realizaçäo do TN2-RU, em indivíduos com pulmöes homogêneos