These protein sequences are shown here in the context of related (orthologous) sequences, such as RfpD. These network representations were built from sequence alignments. They show that FaRLiP sequences (red) are more similar to each other than to other related sequences. For PsbF, FaRLiP sequences appear to form two neighboring clusters, not one; however, this can likely be explained as noise from the small size of this protein (approx. 45 aa). Overall, these data support optional FaRLiP genes representing distinct evolutionary lineages. Sequence similarity networks built with SplitsTree. Sequences available viaSTAR Methods. See alsoTables S8,S9, andS10.