Results of GO enrichment analysis of genes identified as under positive selection are shown in Supplementary Table 4b,d,f). Additionally, we performed GO enrichment analysis on genes estimated to be gained or lost on the terminal branches of each clade32 (Supplementary Table 5a–d). As expected most of the enriched GO terms mapped to functions associated with horizontally transferred elements such as CRISPRs (Clustered Regularly Interspaced Short Palindromic Repeats).