We have characterised the chloroplast genomes of green plants (an ulvophyte, a prasinophyte, charophyte lineages, and embryophyte lineages), and we found that known embryophyte unique operons and introns originated not from early embryophytes but from a charophyte ancestor (The chloroplast genomic maps of Coleochaete and Spirogyra will be presented). In a phylogeny produced from the evolution of operons, genes, and introns, basal charophytes do not contain introns found in the more derived charophytes, and the most derived charophytes and all embryophytes are defined by the presence of clpP and 3 rps12 operons containing trans-splicing rps12. We discuss here the likely charophyte sister to embryophytes and the Antithetic hypothesis of embryophyte origin.

Key words: charophytes, Coleochaete, intron, operon, Phylogenomics, rps12