Estudo eletroforético da dinâmica de variação genética em três taxa ribeirinhos ao longo do rio Solimões, América do Sul

Abstract

INTRODUÇÃOAs espécies ribeirinhas formam um sistema experimental ótimo para o estudo do fluxo genético e da dinâmica da variação genética.

Genetic variation of Calycophyllum spruceanum in the Peruvian Amazon Basin, revealed by amplified fragment length polymorphism (AFLP) analysis

“…Molecular markers have been employed to assess the possible role of hydrochory in mediating gene flow in a number of plant species whose habitats are subject to periodic inundation (Arens et al 1998; Kudoh & Whigham 1997; Wolff et al 1997). In a study of isozyme diversity within three legumes sampled along a 1700 km stretch of the Amazon River, Hill et al (1978) were able to correlate observed levels of genetic variation with the adaptive strategies of the taxa. However, no clear pattern regarding the influence of river structure and hydrochory on genetic variation within taxa was evident, possibly because the five isozyme systems employed provided insufficient polymorphism to resolve relationships.…”

“…In addition, it was anticipated that data would allow hypotheses concerning the role of hydrochory in gene flow to be tested at a macrogeographic level. Finally, few systematic molecular genetic studies on indigenous trees exist in the Amazon (Hill et al 1978; Kanashiro et al 1997) and analysis of C. spruceanum may therefore provide data of general relevance for the use and conservation of other trees with similar ecology and reproductive biology in the region.…”

Evidence for spatial structure and directional gene flow in a population of an aquatic plant, Potamogeton coloratus

“…For example, in an isozyme study of the pattern of genetic differentiation among populations of the clonal perennial herb Mimulus caespitosus Greene growing in and by the side of watercourses in the Washington Cascades, Ritland (1989) found no sign of unidirectional gene flow within streams. In contrast, a study by Hill et al (1978) of the genetic make-up of populations of three amphibious, shrubby legumes growing on the banks of rivers in Brazil produced some qualitative indication that water flow might influence genetic structure. Barrett et al (1993) pointed out that there is little theoretical work on which to base predictions and posed the question of whether dispersal is random with respect to distance in running water.…”

Ecologia da reprodução de duas especies de Mucuna (Leguminosae, Faboideae, Phaseoleae)

“…*P<0,05; **P<0,01; ns -não significativo.Ambas as espécies apresentaram parâmetros de variabilidade genética similares: número médio de alelos observados (Ap) de 1,80 em M. urens e 1,76 em M. japira, número efetivo de alelos por loco (Ae) de 1,53 em M. japira e 1,49 em M. urens, que não foram significativamente diferentes. Cabe ressaltar que estes valores são similares aos encontrados para outras espécies de Leguminosae (Faboideae), mas um pouco menor quando comparado com algumas espécies de Bauhinia, Mimosa e Pithecellobium(HILL et al 1978, O'MALLEY & BAWA 1987, SANTOS 1994. Também podemos ressaltar que estes valores dos índices de diversidade gênica são maiores para estas duas espécies de Mucuna do que para outras lianas(FOSTER & SORK 1997).…”