Fig. 4

Template and coding strand targeting of spacers. A Schematic representation of a spacer targeting the template strand and a spacer targeting the coding strand inside an ORF. Spacers targeting the coding strand are also able to base pair with and target transcribed RNA. B Fraction of Escherichia spacers targeting template (blue) and coding (orange) strand by subtype. C Fraction of Moraxella spacers targeting template and coding strand by subtype. D Fraction of spacers targeting template and coding strand for type I and type IV subtypes. E Fraction of spacers targeting template and coding strand for type II and type III subtypes. F Fraction of spacers targeting template and coding strand for type I. Spacers are grouped based on which other types of Cas effector genes are present in the genome. G The same as F but for type II spacers. The significance of strand bias is calculated with a binomial test, and a p-value < 0.01 is indicated with an asterisk. Additional file 2 contains the strand targeted of each spacer and allows to extract the strand bias for each taxon