Meta-populations are populations which are subdivided into many ephemeral, weakly interacting subcomponents. The genetic properties of metapopulations are determined, in large part, by genetic processes accompanying the extinction and recolonization of the local subcomponents. These processes have been the subject of recent theoretical analysis but are not well studied in nature. This study will investigate the population genetic properties of a meta-population of Silene alba, an herbaceous plant that has been the subject of the detailed, long-term demographic analysis required as background data for the study of meta-populations. The basic question to be asked in this project is whether the repeated extinction and recolonization of local demes acts to increase or to diminish genetic differentiation, relative to a similarly subdivided population but without extinction and recolonization. The work will include studies of the genetic properties of the meta-population, additional demographic studies geared towards understanding mechanisms of gene flow, and extension of the theoretical models. Experimental studies of pollen and seed flow, and recruitment from the seed bank, will evaluate sources of gene flow, both into established populations and as part of the process by which new populations are established. Extension of theory will be guided, in part, by the results of the empirical work. //
