Chloroplast DNA-based phylogeny of Asian Pinus species (Pinaceae)

The genus Pinus includes over 90 species with approximately 24 species native to Asia. We have analyzed the chloroplast (cp) DNA variation of 18 Pinus species, including 15 Asian, two Eurasian, and one European species using seven restriction enzymes and ten non-overlapping probes and inferred their phylogenetic relationships. Results of phenetic and cladistic approaches to phylogeny reconstruction were largely in agreement, suggesting two major lineages within the genus and confirmed the ancient character of haploxylon and diploxylon subgenera. Species from section Parrya appear to have diverged earliest from the hypothesized phylogenetic centre for the haploxylon pines, with P. bungeana and P. gerardiana forming two basal, monotypic lineages. The range of estimated pairwise nucleotide substitutions per site ( {Mathematical expression}) was higher among haploxylon pines than among diploxylon species. CpDNA divergence was found to be low within the section Sylvestres, relative to the divergence among haploxylon species, suggesting that the radiation of this group of taxa from its common ancestor occurred after the diversification of other groups. The low cpDNA divergence in this subsection corroborated earlier evidence for its phylogenetic cohesiveness and existence as a monophyletic group.