XVI International Botanical Congess

Genetic variation of organelle DNA between two remaining populations of Cycas taitungensis, was assessed. In contrast to the low genetic polymorphism revealed by allozyme, remarkably high variation of both cp- and mtDNA, with nucleotide diversity of 0.013 and 0.017 respectively, was detected in the relic species. However, no genetic differentiation between populations was found to exist. According to the fossil pollen record, the populations of this cycad were once widespread on the island and its evolution was influenced by glaciation events. The patterns of high variability suggested a history with long distance migration from extinct populations into the refugee. Intramolecular recombination and lineage sorting were other possible mechanisms responsible for the high genetic polymorphism.