Gene maps of Oltmannsiellopsis and other chlorophyte cpDNAs. Genes (filled boxes) outside each map are transcribed clockwise. The transcription direction of the rRNA genes is indicated by arrows. Genes shown in yellow, blue and red map to the IR, LSC and SSC regions in Mesostigma cpDNA, respectively. On the Oltmannsiellopsis map, genes characteristic of the LSC region that reside in the single copy region corresponding to SSC in both Oltmannsiellopsis and Pseudendoclonium cpDNAs are denoted by asterisks. Genes absent from Mesostigma cpDNA are shown in grey. tRNA genes are indicated by the one-letter amino acid code followed by the anticodon in parentheses (Me, elongator methionine; Mf, initiator methionine). A total of five introns (open boxes) were identified, some of which feature ORFs (narrow boxes).