Fig 1. Comparative genomics of wmk and its homologs in wMel and male-killing strains.

Prophage WO gene regions containing wmk, wmk-like homologs, and CI genes cifA and cifB are listed by Wolbachia strain in bold and then prophage. At least one wmk homolog is associated with each Wolbachia-induced male killing strain. Genes pointing in the same direction are on the same DNA strand. The distance between wmk and cifA is approximately 5 kb. Shading highlights homologs in each strain. (*) wmk homologs are annotated as transcriptional regulators in the Wolbachia reference genomes and encode helix-turn-helix XRE domains (S4 Table). (**) While wBif reportedly induces weak CI after temperature treatment [8], the assembled genome does not contain cifB.