Random amplified polymorphic DNA (RAPD) variation among populations of theinsular endemic plant Campanula microdonta (Campanulaceae)

RAPD variation was examined in nine populations of Campanula microdonta Koi dz., endemic to the Izu Islands, Japan. Ninety-eight bands were obtained fo r all populations, 94% of which were polymorphic at least within a populati on. Shannon's H values were calculated: these have frequently been used in RAPD studies to estimate genetic diversity. The values within populations d id not correlate with the allozyme gene diversity estimated by a previous s tudy or with distance from the Japanese mainland. The possible reasons for this discrepancy are different selection regimes between the two markers, h igher RAPD mutation rates, and each marker's different coverage of genomes. Cluster analysis of genetic similarities suggested that colonization of ea ch island probably occurred once, except for Miyake Island, where immigrati on has occurred at least twice. (C) 2001 Annals of Botany Company.