Molecular Phylogeny And Biogeography Of Pseudotsuga

Pinaceae, a dominant and conspicuous forest component in the Northern Hemisphere, is the largest and most important family of the Coniferales. Most genera of the pine family show intercontinental disjunctions, such as Pseudotsuga in eastern Asia and western North America, and therefore give us opportunities for testing biogeographical theories like vicariance and dispersal. On the other hand, the chloroplast and mitochondrial genomes of Pinaceae are paternally and maternally inherited, respectively, providing ideal markers for reconstructing phylogenies, in particular those with reticulate evolution. In this study, we sampled all eight species of Pseudotsuga and constructed molecular phylogenies of the genus based on sequence analyses of three cpDNA and two mtDNA fragments, using two species of Larix ( L. laricina and L. griffithii ) as outgroups. Then, the biogeographical history of Pseudotsuga was discussed. The main results are summarized as follows:(1) The most parsimonious trees obtained from separate and joint analyses of the three cpDNA regions ( trnfM-trnS,rpl20, trnP ) are highly congruent in topology, suggesting that the eastern Asian Pseudotsuga is a monophyletic group, in which P. japonica from Japan...