XVI International Botanical Congess

Genetic variation of both organelle and nuclear DNA in endemic and rare taxa (Quercus formosanus, Amorphophallus spp, Cycas taitungensis, and Cunninghamia konishii) of Taiwan was assessed. Remarkably high polymorphism of cpDNA was detected within species, and showed little differentiation among populations. Both lineage sorting and long-distance dispersal during postglacial recolonization could lead to such patterns of variability. In contrast, RAPD data suggest more recent, limited gene flow, which has resulted in significant population differentiation. In contrast to the high genetic variation in the above species influenced by glaciation events, organelle DNA within and between Begonia species is extremely low. These results suggest that patterns of variation in endemic taxa are influenced by a variety of evolutionary processes whose importance varies during the history of species.