In contrast to the great effort dedicated to figuring out the demographic consequences of dispersal, the effects of seed dispersal on the genetic structure of populations have received far less attention. Plant genes are dispersed either through haploid pollen or diploid seeds, and inheritance may be maternal (chloroplast DNA in angiosperms), paternal (chloroplast DNA in conifers), or biparental (nuclear DNA). Recent studies have revealed that zoo-chorous plant species have characteristically high levels of within-population genetic variation compared to other seed dispersal syndromes, and that such variation is associated with extensive gene flow via seed dispersal in addition to outbreeding via pollen flow. Moreover, when zoochorous populations are structured in space (e.g., fragmented populations, metapopulations), frugivores have shown to strongly influence the among-population gene flow via seeds. The tools provided by microsatellites have also provided unequivocal genetic fingerprints of source mother plants in the population, revealing a marked heterogeneity in the genetic composition of the seed rain in different microhabitats, and also making it possible to know the fraction of seeds that come from other populations. Therefore, despite their low occurrence in nature, LDD events can now be tracked at different scales (i.e., landscape, regional, or continental) by these genetic markers.
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