Molecular phylogeography of a pan-tropic sea-drift seed dispersalplants. Hibiscus tiliaceus

摘要

Hibiscus tiliaceus (Malvaceae) is one of the sea-drift seed dispersal plants distributed in the littoral areas of tropics of the Old World. Hibiscus prenambucensis, morphologically and ecologically similar to H. tiliaceus, is distributed only in tropics of the New World. As the two species may have arisen from the most recent common ancestor, they will provide an excellent example to study phylogeography of pan-tropic sea-drift seed dispersal plants. In order to clarify the phylogenetic relationships of the two species, we performed molecular phylogeographic analysis using several coding regions (ndhF, matK) and non-coding regions (atpB-rbcL, accD-psaI, 5'trnK-matK, matK3'-3'trnK-psbA, rpl16 intron) of chloroplast DNA (total ca. 8,000 bp). The resultant tree consisted of two major clades, each of which includes both H. tiliaceus and H. pernambucensis. As H. pernambucensis is nested in the clade that is mainly consisted of H. tiliaceus in each of the two major clades, it is suggested that H. pernambucensis could be differentiated from H. tiliaceus. One of the major haplotypes of H. tiliaceus is also found in H. pernambucensis, which may suggest parallel evolution of H. pernambucensis or gene exchange between the two species.