Proportional comparison of the gene structures of 2CP in Arabidopsis thaliana (At), Selaginella moellendorffii (Sm), Physcomitrella patens (Pp) and Chlamydomonas reinhardtii (Cr). ESTcovered 2CP genes are shown in green, putatively non-expressed in blue. The vertical lines connect corresponding splice sites. The numbers represent positions of corresponding amino acids in the alignment shown in Fig. 5A and the relative splice sites within the corresponding codon.