Fig. 3.

—Recurrent loss of 4.5S RNA (the RNA component of the plastidial SRP specified by the ffs gene) in ochrophytes. The figure shows a segment of a multiple sequence alignment of cpSRP54 (the protein component of the plastidial SRP) including two motifs critical for binding of the 4.5S RNA molecule. The presence of a discernible ffs gene in the pt genome of the respective species is indicated on the left by a red square. Note the perfect correlation between the conservation of the 4.5S RNA-binding motif in cpSRP54 (shown in red beneath the alignment) and the presence of the ffs gene.