High level of variation at Abies alba chloroplast microsatellite loci in Europe.

Based on two polymorphic chloroplast microsatellites that had been previously identified and sequence characterized in the genus Abies, genetic variation was studied in a total of 714 individuals from 17 European silver fir (Abies alba Mill.) populations distributed all over the natural range. We found eight and 18 different length variants at each locus, respectively, which combined into 90 different haplotypes. Genetic distances between most populations were high and significant. There is also evidence for spatial organization of the distribution of haplotypes, as shown by permutation tests, which demonstrate that genetic distances increase with spatial distances. A large heterogeneity in levels of diversity across populations was observed. Furthermore, there is good congruence in the levels of allelic richness of the two loci across populations. The present organization of levels of allelic richness across the range of the species is likely to have been shaped by the distribution of refugia during the last glaciation and the subsequent recolonization processes.