Fig. 2.

—Protein-coding genes shared by different plastid genomes. The Venn diagram in (a) summarizes the number of protein-coding genes shared between the ptDNAs of Cyanophora, Glaucocystis, Gloeochaete, and Cyanoptyche (*the ptDNA of Cyanoptyche gloeocystis SAG 4.97 is partially sequenced). ORFs of unknown function exclusive to a single genus were not considered in the comparison. (b) The shared plastid protein-coding genes between the three Archaeplastida lineages. Note that the rbcL and rbcS genes from red algae are of different origin (proteobacterial) to the glaucophyte and viridiplants (both of cyanobacterial provenance). Table (c) lists the names of the plastid genes shared between the Archaeplastida lineages and those exclusive to each group.