Phylogenetic relationships of RedCAPs. Thirteen available full-length sequences from red algae and algae with secondary plastids of red algal origin, with an aligned 146 amino acid positions, thereof 99 phylogenetically informative, were analysed. A Maximum likelihood tree was inferred under the CpRev + G model. Bootstrap values for Neighbor-joining (10,000 replicates) and Maximum likelihood analysis (100 replicates) as well as posterior probabilities (one million generation, 25% burn-in) are given. Accession numbers of analysed sequences are listed in Table S1, see Additional file 1, for sequence alignment see Additional file 6.