Due to their isolation, oceanic islands provide shelter for original ecosystems with clear geographical limits. In such context, French Polynesia offers an insular system with highly isolated islands, en even more while considering lagoonal species.
The black-lipped pearl oyster Pinctada margaritifera comes as one of the best example of species occurring almost exclusively in lagoons. Populations of this species are essentially distributed in lagoons and can therefore be separated by several hundreds of kilometres. In addition of being isolated lagoonal species have also undergone several sea levels fluctuations responsible for reduction or complete loss of genetic diversity as in some other species (i.e. fish).
In this context of population natural evolution one must also include the role and the impact of human activity. Indeed many juveniles of P. margaritifera have been and are still translocated from a lagoon to another to supply oyster farms.
Because translocation causes genetic homogenization of wild populations from distinct atolls, it seems necessary to evaluate the actual genetic diversity of wild populations of P. margaritifera, thanks to genetics markers like microsatellites and introns (involved in the nacreous layer synthesis) in order to replace this level of diversity and the spatial variability of this diversity in a larger evolutionary model of populations and species.
