Gene maps of Staurastrum and Zygnema cpDNAs. Genes (filled boxes) shown on the outside of each map are transcribed in a clockwise direction, whereas those on the inside of each map are transcribed counterclockwise. Genes absent from Marchantia cpDNA are represented in beige. Gene clusters shared with Marchantia cpDNA [GenBank:NC_001319] are shown as alternating series of green and red boxes. Genes present in Marchantia cpDNA but located outside conserved clusters are shown in grey. Gene clusters shared by the two zygnematalean cpDNAs are represented by labelled bars outside each map. Genes containing introns (open boxes) are denoted by asterisks. Dispersed repeat regions in Zygnema cpDNA that contain short tandem repeats are denoted by symbols. The repeat units in these regions are as follows: filled squares, TAGAA; open squares, TTCTA; filled circles, GTAT; open circles, ATAC; filled triangles, CTTA. Note that filled and open symbols with the same geometric shape represent the repeat regions of which the sequences are in inverted orientation relative to one another. The intron sequences bordering the rps12 exons (rps12a and rps12b) are spliced in trans at the RNA level. tRNA genes are indicated by the one-letter amino acid code (Me, elongator methionine; Mf, initiator methionine) followed by the anticodon in parentheses. The ORFs unique to Staurastrum or Zygnema cpDNA are not indicated (see [GenBank:AY958085] and [GenBank:AY958086] for more details).