Overview of identified MIP subfamilies in green plants. A schematic tree showing the evolutionary relationship between green plant lineages is combined with a table summarizing the distribution of plant MIP subfamilies. MIPA-E constitutes novel subfamilies identified in this study. The PIP and the GIP subfamilies appear to have evolved before the split of the chlorophyte and the streptophyte lineages. For all plants except S. lycopersicum and P. incise the number of MIPs is derived from annotations of whole genomes [9, 55, 56]. a) The occurrence of MIPs in S. lycopersicum is based on an extensive analysis of ESTs .