Article

We examined the genetic variation at 12 isozyme loci at 14 populations of Matthiola (Brassicaceae) representing the distribution of the species Matthiola incana, M. fruticulosa and M. tricuspidata in the Sicilian insular system and adjacent mainland areas to gain insight into the levels of variation. While the low polymorphism indicators for M. incana subsp. incana are consistent with its presumptive origin through cultivation and the associated lack of gene flow, M. incana subsp. pulchella and M. incana subsp. rupestris have only slightly higher indices of polymorphism and they are probably neo-endemics. By contrast, the Sicilian populations M. tricuspidata and M. fruticulosa subsp. fruticulosa have maintained a moderate-to-high polymorphism through an abundant genetic interchange. These two latter species are also closer genetically than each of them to M. incana.