Chromosomal distribution and segmental duplication events for PP2C genes in Arabidopsis (A) and rice (B). The chromosome number is indicated at the top of each chromosome representation. Green boxes indicate duplicated chromosomal segments retained from the most recent polyploidy event. Only duplicated regions containing PP2C genes are shown. Grey lines connect paralogous sister gene pairs in duplicated blocks. Potentially duplicated gene pairs as described in the text are marked with numbers in orange squares. Gene clusters that contain the members with high levels of sequence similarity, and likely have evolved via tandem duplications are marked with number in red rectangles.