Journal of Molecular Evolution © Springer-Verlag New York Inc. 1992 Molecular Phylogenies of Plastid Origins and Algal Evolution

Summary. An overview of recent molecular anal-yses regarding origins of plastids in algal lineages is presented. Since different phylogenetic analyses can yield contradictory views of algal plastid ori-gins, we have examined the effect of two distance measurement methods and two distance matrix tree-building methods upon topologies for the ribu-lose-l,5-bisphosphate carboxylase/oxygenase l rge subunit nucleotide sequence data set. These results are contrasted to those from bootstrap arsimony analysis of nucleotide sequence data subsets. It is shown that the phylogenetic nformation contained within nucleotide sequences for the chloroplast-encoded gene for the large subunit of ribulose-l,5-bisphosphate carboxylase/oxygenase, integral to photosynthesis, ndicates an independent origin for this plastid gene in different plant taxa. This finding is contrasted to contrary results derived from 16S rRNA sequences. Possible explanations for dis-crepancies observed for these two different mole-cules are put forth. Other molecular sequence data which address questions of early plant evolution and the eubacterial origins of algal organelles are discussed