Nuclear and plastid DNA data confirm that Sedum tosaense (Crassulaceae) has a disjunct distribution between Pacific mainland Japan and Jeju Island, Korea

Abstract

Our molecular phylogeographic analyses based on the nrDNA ITS and cpDNA trnLF of Sedum tosaense populations in the Shikoku District, Japan and Jeju Island, Korea suggested a disjunct distribution. Plants of S. tosaense from the two regions comprised a well-supported clade consisted of plants from Kochi (Shikoku District) and those from Jeju Island; we estimated a divergence time of 0.61 Ma between the Kochi and Jeju populations based on the ITS and partial trnLF. We conclude that: 1) S. tosaense has a disjunct distribution between Kochi and Jeju Island, and 2) plants of this species might have dispersed between Kochi and Jeju Island over water, but not via a land bridge, which flooded before subclade divergence.