COMPARATIVE RESTRICTION SITE MAPPING OF CHLOROPLAST DNA IMPLIES NEW PHYLOGENETIC-RELATIONSHIPS WITHIN RUBIACEAE

Phylogenetic analyses of 33 species of Rubiaceae were performed using chloroplast DNA restriction site mutations. Complete cleavage maps of eight enzymes were constructed for Psychotria bacteriophila and used as a reference in comparisons among other species. The species examined represent 33 genera from 18 tribes and four subfamilies of the Rubiaceae. A total of 268 restriction site mutations was detected, 161 of which were phylogenetically informative. Wagner and Dollo parsimony trees were compared to the classifications of Verdcourt, Bremekamp, and Robbrecht. The Wagner analysis resulted in six equally parsimonious trees with 348 steps and 54% homoplasy. Dollo analysis resulted in a single most parsimonious tree. Most clades were identical in the two analyses. The subfamily Cinchonoideae is paraphyletic. The subfamilies Antirheoideae, Ixoroideae, and Rubioideae are monophyletic, although their circumscriptions differ from previous classifications. Several new phylogenetic relationships are indicated: the tribe Chiococceae (Ixoroideae) groups with Exostema and Coutarea (Cinchonoideae); the subfamily Ixoroideae including tribe Vanguerieae is closely related to Pogonopus, Pinckneya, Calycophyllum, and Mussaenda (Cinchonoideae); and tribe Hamelieae forms a monophyletic group outside the subfamily Rubioideae.