Figure 3.

Comparative organization of dsr (a) and hydrogenase gene (b) clusters. EBS, scaly-foot gastropod endosymbiont; Allo, A. vinosum; Bath, Bathymodiolus sp. endosymbiont; Rift, R. pachyptila endosymbiont; Tint, Thiomonas intermedia K12. Genes are represented by arrows of length proportional to the gene length. Structural genes are represented by hatched arrows (small subunits) or black arrows (large subunits). White arrows without gene names are hypothetical protein genes. Gray bars indicate orthologous genes. Sequence information was retrieved from GenBank.