Gene map of the Nephroselmis astigmatica choroplast genome. Filled boxes represent genes, with colors denoting categories as indicated in Figure 1. Genes on the outside of the map are transcribed counterclockwise; those on the inside are transcribed clockwise. The outermost inner ring indicates the positions of the IR and SC regions. Thick lines in the innermost ring represent the conserved gene clusters between Nephroselmis astigmatica and Nephroselmis olivacea cpDNAs.