9408057 Chapman Molecular data from nuclear and organellar DNA, in conjunction with numerical algorithms for phylogenetic analysis, have revolutionized the study of plant evolution. Dr. Russell Chapman of Louisiana State University has been a leader in the application of these molecular and taxometric methodologies to the analysis of green algae and of so-called lower land plants such as mosses and club-mosses. Focussing primarily on nuclear ribosomal gene sequences, he has shown that the bryophytes (mosses, liverworts, and hornworts), while likely to be the earliest diverging lineages of land plants, are themselves not a single evolutionary unit but a series of terrestrial "experiments." Additional DNA data are being collected to test the phylogenetic affinities of various bryophyte groups, and in particular to assess the utility of the current classification of mosses into 17 distinct suborders. As samples become available, molecular analyses will also be applied to related groups of primitive vascular plants, the lycophytes (club mosses and relatives). In association with morphological and ultrastructural studies underway in other laboratories, the molecular phylogenetic analyses of nuclear ribosomal DNA conducted by Dr. Chapman are providing insight to the direction and tempo of change in plants as they adapted to life on land.
