XVI International Botanical Congess

Marine angiosperms reproduce both sexually and clonally, giving rise to complex and highly productive ecosystems. Understanding genetic structure and gene flow in seagrass species becomes important in the definition of management strategies in coastal areas. Few studies exist on seagrass population genetics, but recent advances in molecular technologies have increased the capability of resolving microevolutionary variation at the DNA level with a number of powerful genetic markers.The polymorphism of microsatellite regions of DNA isolated from a Posidonia oceanica genetic library has been utilized to assess population genetic parameters and genetic diversity within and among populations of this Mediterranean endemic species. Moreover, the polymorphism of several microsatellite loci have been analyzed in adult plants and seedlings, in order to determine the role of sexual reproduction in increasing genetic variability within natural seagrass meadows.It could be established that: limited gene flow exist among populations, clonal growth is important in the maintenance of P. oceanica populations, some of which resulted to be composed by clonal patches of different size, sexual reproduction does not determine a significant increasing in genetic diversity suggesting the existence of self fertilization and inbreeding.