FIG 4.

Arrangement of rhodopsin and carotenoid synthesis genes in different bacteria. (A) Carotenoid synthesis genes (crt) and the gene for synthesizing the chromophore retinal (blh) are in red. Rhodopsin variants are shown in green. In blue are genes whose products are known to respond to light. tRNA in black might be involved in lateral gene transfer. Labels above genes denote gene products. (B) Gene arrangement in the Flavobacteriia single amplified genome (SAG) MS024-2A; the PR is next to the conserved cluster of highly expressed genes that includes ribosomal protein, RNA polymerase subunit alpha, and transcription factors genes, in addition to Sec secretion pathway and TCA cycle genes.