MOLECULAR EVOLUTION AND PHYLOGENETIC UTILITY OF THE CHLOROPLAST RPL16INTRON IN CHUSQUEA AND THE BAMBUSOIDEAE (POACEAE)

Phylogenetic relationships within Chusquea, a diverse genus of neotrop ical woody bamboos, and among selected members of the Bambusoideae wer e explored using rpl16 intron sequence data from the chloroplast genom e. Mechanisms of mutation, including slipped-strand mispairing, second ary structure, minute inversions, and base substitutions, were examine d within the rpl16 intron, and their effects on sequence alignment and phylogenetic analysis were investigated. Thirty-five bamboo sequences were generated and two separate matrices were analyzed using maximum parsimony. In the first, 23 sequences from Chusquea, 1 of Neurolepis, and 3 outgroups were included. Neurolepis was supported as sister to C husquea, Chusquea was strongly supported as a monophyletic lineage, an d three species of Chusquea subg. Rettbergia were resolved as the most basal clade within the genus. In the second analysis, 15 sequences, 1 4 from across the subfamily and 1 outgroup, were included. A Bambusoid eae clade was recovered with the Olyreae/Parianeae (herbaceous bamboos ) and the Bambuseae (woody bamboos) each supported as monophyletic. Tw o clades corresponding to temperate and tropical woody bamboos were de rived within the Bambuseae and the tropical taxa were further split in to New World and Old World clades. The rpl16 intron in bamboos was fou nd to be susceptible to frequent length mutations of multiple origins, nonindependent character evolution, and regions of high mutability, a ll of which created difficulties in alignment and phylogenetic analysi s; nonetheless the rpl16 intron is phylogenetically informative at the inter- and intrageneric levels in bamboos. (C) 1997 Academic Press.