9306462 Manhart Among the green algae, both unicellular and multicellular forms, there proves to be a greater diversity of genomic structures and arrangements than among all the flowering plants. Some of these genomic markers indicate lineages that are the likely close relatives to land plants, sharing features of gene arrangement in their chloroplasts and other fine-scale genetic structures. Dr. Manhart at Texas A&M University is studying several aspects of chloroplast genome structure and function in green algae in order to characterize features that mark particular phylogenetic lineages. Particular attention is focused on organization of the rps12 gene, the presence of introns in chloroplast transfer RNA genes, and the presence of introns in the photosynthetic gene rbcL. In addition, DNA sequencing will be done for the 16S ribosomal gene in order to make comparisons of mutational differences between green algae, in order to reconstruct their genealogical connections. %%% This research involves the use of chloroplast DNA (cpDNA) gene sequences and fine details of cpDNA organization to test hypothesized phylogenetic relationships in green plants and to increase our understanding of the molecular evolution of cpDNAs. Aspects of chloroplast structure and function should prove useful in delimiting those green algae that are the likely closest relatives to land plants.
