WP 2 - Description of work
1.The spatial genetic structure will be explored with nuclear microsatellites already developed and tested for the species selected. The structure of genetic diversity at local and regional scales will be analyzed using methods of landscape genetics, especially Bayesian inference of population differentiation (GENELAND, 18) and Mantel tests, to look for correlation between genetic structure and geographic distance, altitudinal and humidity gradients.
2. Taxon delimitation between Euterpe precatoria var. precatoria and var. longevaginata will be analyzed with a “blind procedure” as described by Duminil et al. (20)also applying Bayesian inference of genetic structure (STRUCTURE Analysis, 65) on the basis of nuclear microsatellites and chloroplastic polymorphisms of non-coding sequences.
3. The impact of the human pressure on habitat (fragmentation) and intensity of species use (logging and extractivism pressure) on genetic diversity, inbreeding, gene flow in natural palm populations will be analyzed using nuclear and chloroplastic microsatellites data.
All species selected for genetic studies (Astrocaryum chambira, Astrocaryum malybo, Astrocaryum standleyanum, Bactris gasipaes var. chichagui, Oenocarpus bataua, Euterpe precatoria) are exploited and managed in some way in their natural habitats, as providers of useful products (edible fruits and seeds, palm hearts, fibers, wood). Nuclear microsatellites are extremely powerful in population genetics studies and are now fully operational in palms (32, 120). In addition, microsatellites libraries are available or will be completed during the first year of the project for all the palms selected: Astrocaryum (Freville et al. submitted, Pintaud et al. in prep.), Bactris gasipaes (141, 107, 67), Oenocarpus (47, 144), Euterpe (32). Three Chloroplastic sequences non-coding regions, trnQ-rps16, trnD-trnT and PsbC-trnfM have been fully studied in the selected species (120, 142, 152, Freville et al. submitted) and many more are now available (75, 76). The sequences studied revealed polymorphisms highly informative about structure of populations at a regional scale, including short and medium-sized inversions, direct repeats, micro- and minisatellites.
