Our investigation aims to understand the genetic structure and evolutionary history of Petagnaea gussonei, an ancient and endangered species belonging to the Saniculoideae subfamily (Apiaceae). It is paleoendemic to Sicily, with a small number of populations in the Nebrodi Mountains. Atotal of seven chloroplast microsatellite repeat loci and 12 AFLP primer combinations were used to screen 115 individualscorresponding to 17 populations. The ratio of seed to pollen flow was also calculated using the modified Ennos equation. A relatively high level of genetic diversity was detected with AFLPs (e.g., 0.045\H\0.278), and a moderate variation was also found using cpSSRs (0\Hk\0.667). Two different haplotypes (B and W) wereidentified, with five populations being monomorphic for haplotype B. There was no genetic differentiation on the basisof haplotypic frequency (GST) and similarity (RST), and no phylogeographic structure was detected among the populations. AFLP values also confirmed that the populations arenot very genetically differentiated. The principal component analysis based on pairwise genetic differences showed threegroupings without a geographical correlation. The AMOVA analysis indicates that theamount of variation is higher withinpopulations (82 %) than among populations (18 %). Results of the pollen flow/seed flow ratio indicated positive values foreach population, indicating that gene flow by seed is not more efficient than by pollen. Instead, the total pollen/seed flow for all population presents a negative value, suggesting that pollen dispersal does not appear to be more effective over thelong range for gene flow than seed dispersal. This differentiation level supports the hypothesis that the fragmentation and isolation of the residual populations is in progress. Thisphenomenon is due not only to post-ice age climate changes, but also to direct and indirect anthropic actions.
|Number of pages||15|
|Journal||Plant Systematics and Evolution|
|Publication status||Published - 2013|
All Science Journal Classification (ASJC) codes
- Ecology, Evolution, Behavior and Systematics
- Plant Science