Physical and gene map of the green alga Nephroselmis chloroplast genome, showing the typical structural arrangement found in land plants. Genes located on the inside of the map are transcribed counterclockwise, and genes on the outside are transcribed clockwise. The inner circle shows where the Small Single-Copy region (SSC), Large Single Copy region (LSC) and Inverted Repeats (IR), are located. The thick lines on the actual map are the IRs. Figure from Turmel et al. (1999). © 1999 National Academy of Sciences, U.S.A. The "B" copy (IR-B) of the inverted repeat is the copy that is missing in legume taxa in the IRLC.
Structure of plant chloroplast genomeMartin F. Wojciechowski
Turmel, M., C. Otis, and C. Lemieux. 1999. The complete chloroplast DNA sequence of the green alga Nephroselmis olivacea: Insights into the architecture of ancestral chloroplast genomes. Proceedings of the National Academy of Sciences USA 96: 10248-10253.