Gene content and organization of PR gene–containing genome segments from AND4 and BAA-1116.

<p>PR (<i>prd</i>) and chromophore synthesis genes required for functional photoprotein are shown in red, transposase genes in blue. Yellow shading highlights a genomic region predicted by the program IslandPick to have originated from lateral gene transfer <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000358#pbio.1000358-Langille1" target="_blank">[38]</a>. In accordance with the divergent ancestry of the <i>prd</i> gene and retinal biosynthesis genes compared to flanking genes (<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.1000358#pbio.1000358.s003" target="_blank">Table S1</a>), the presence of a truncated transposase indicates that the genome region in AND4 containing <i>prd</i> has been modified by historical lateral gene transfer events.</p>