Molecular phylogeny of Dipterocarp Species Using Nucleotide Sequences of Two Non-coding Regions in Chloroplast DNA.

A total of 53 dipterocarp species belonging to ten genera were studied to examine phylogenetic relationships using the sequences of two non-coding regions in chloroplast DNA. Phylogenetic analysis showed the Selangan Batu, Yellow Meranti and White Meranti of the genus Shorea were monophyletic, while the Red Meranti was divided into three natural clades. The relationships in the Red Meranti could not be ascertained because of an insufficient number of nucleotide substitutions. The White Meranti was clustered with sect. Pelltacme and situated in an outer position of the genus Hopea, Neobalallocarpus and Parashorea although the bootstrap probability was not high. Two of the three deciduous Shorea species collected in Thailand, one belonging to White Meranti and the other to sect. Pelltacme based on morphological and anatomical evidence, were found to constitute a monophyletic group clustering with the other White Meranties. The third species in the Selangan Batu was clustered with the other Selangan Batus. This suggests that the deciduous character in the genus Shorea has evolved independently in different lineages. The divergence within sections of the genus Shorea was largest in sect. Mutica and smallest in sect. Richetioides. The genera Shorea and Hopea were more divergent than the other genera. These results suggest that they are the groups of phylogenetically more diversified species.