Figure 2. Type I CRISPR regions.

A) CRISPR-IA region from Syn OS-A (top) and Syn OS-B′ (bottom). The cas gene cluster is indicated by a grey bracket. B) CRISPR-IB region. Gene identifiers are shown above or below each gene, excluding the GenBank locus tag prefix ‘CYA_’ (for Syn OS-A) or ‘CYB_’ (for Syn OS-B′). Genes are color-coded following the COG-based IMG convention (http://img.jgi.doe.gov), (described in Figure 4), except that genes annotated as “hypothetical protein” are in grey, genes with no putative ortholog in the other genome are in red, and genes annotated as transposases are in black. Orthologous genes are indicated by yellow blocks. Detailed information on each gene is available in Table S3.