Fig. 1

Typical organization of adaptation modules that include cas4 genes. Most common organizations of adaptation modules containing cas4 gene are shown. Genes are shown by block arrows according to the transcription direction and are not to scale. Homologous genes are color-coded and identified by a systematic name and a legacy name (indicated by an asterisk). Cas4 family genes are indicated by thick outline. CRISPR-Cas system subtypes found in association with each module are indicated. Notably, the adaptation modules of the I-B and I-D loci include cas6 genes