We used restriction fragment analysis of chloroplast, nuclear, and mitochondrial DNA to study phylogeny in the genus Pseudotsuga. Total genomic DNA from one outgroup (Larix occidentalis Nutt.) and five Pseudotsuga species from Japan, mainland China, Taiwan, and North America were digested with 20 restriction enzymes, blotted, and probed up to 17 times with cloned DNA fragments. A total of 38 shared fragment characters were subjected to Wagner parsimony analysis coupled with bootstrapping to evaluate statistical significance of the phylogenetic trees. The complex patterns that we observed for actin gene fragments were evaluated via a Fitch–Margoliash distance-matrix analysis. Both parsimony and distance-matrix analyses indicated that relationships among species in the genus coincide with their current geographic distribution; genetic similarity declines with migration distance around the Pacific Rim. The Asian and North American species form well-differentiated and statistically significant monophyletic groups. Pseudotsuga japonica is the Asian species closest to the North American species. Affinities to the outgroup Larix occidentalis suggest that Pseudotsuga originated in North America and then migrated into Asia. Key words: parsimony, phylogeny, biogeography, conifer, Pinaceae.
PHYLOGENETICS OF THELISIANTHIUS SKINNERI(GENTIANACEAE) SPECIES COMPLEX IN PANAMA UTILIZING DNA RESTRICTION FRAGMENT ANALYSIS