Picconia azorica (Tutin) Knobl. (Oleaceae) is an endangered species, endemic to the Azores.
Samples from 31 populations in 8 islands were genotyped using 8 newly developed nuclear
microsatellite markers. From the amplified loci, 81% were polymorphic across all
populations and the species showed a relatively high total genetic diversity (HT¼ 0.7).
Several populations were close to Hardy–Weinberg equilibrium while others presented
positive FIS values (0.02–0.2). The largest proportion of genetic variation (98%) occurred
within populations and the level of differentiation between populations, was generally
low, although 27% of the population pairwise comparisons showed relatively high differentiation
values (0.25 RST 0.65). Relatively high levels of gene flow were also found
among most populations. Using the Bayesian clustering method implemented in STRUCTURE
we found a particular genetic pattern in Corvo samples, and also similarities between
Santa Maria, São Miguel and Flores populations. Considerable levels of genetic admixture
within P. azorica populations might have resulted from: (i) fruit dispersal by native birds;
and/or (ii) human mediated dispersal between islands. Our results revealed the existence
of some genetically depauperate populations needing specific conservation measures, and
indicate that arbitrary translocation of individuals between islands should be avoided.