9407606 McCourt In an intriguing and challenging application of both molecular and morphological data to a problem in phylogeny, Professor Richard McCourt at DePaul University will be studying the algal group known as stoneworts, the Charophyta. Representatives of all seven genera of living members of the group will be analyzed for a number of genes by nucleotide sequencing methods, to acquire data on mutational differences among the species. Morphological features of these same taxa along with data on the rich record of fossil forms of these algae, acquired in collaboration with French paleobotanical colleagues, will be integrated with the DNA results to reconstruct the phylogenetic relationships of the charophytes. The charophytes are relatively large and complex for algae; they have growing regions at the apex of branches and flagellated sperm cells that are more similar to those of certain land plants than to other green algae. As one of the algal groups closest phylogenetically to the land plants, the charophytes are likely to show evolutionary adaptations that will help understand the sequence of changes in the origin of land plants. As well, their fossil record provides an opportunity to calibrate rates of molecular change in genes.
