THE CHLOROPLAST GENE RPS4 AS A TOOL FOR THE STUDY OF POACEAE PHYLOGENY

Phylogenetic analyses of 28 Poaceae species based on the chloroplast rps 4 gene are presented using parsimony and distance methods. Two monocots from other families were used as outgroups. The chloroplast gene rps4 was amplified, cloned, and sequenced for each species. The inferred phylogenetic trees were compared to recent classifications and are shown to fit their general features. There is a dichotomy in our tree between the pooid group and the other grasses. This is in contradiction with other molecular phylogenies, where the bamboos appear first within the family. This result led us to discuss some hypotheses about the relationships of the bambusoids with the other groups of grasses, and also about the relative position of rice and bamboo, which are found close to each other in our trees.