Rickettsiales are widely regarded as the ancestor of eukaryotic mitochondria through endosymbiosis. Cyanobacteria are widely regarded as the ancestor of eukaryotic chloroplasts through endosymbiosis.
These two organelles bear striking similarities in terms of structure and mechanics. There seems to be plenty of information regarding speculation on the endosymbiosis that led from these free-living organims to the organelles. However I can't seem to find much on speculated relationships between these organisms in terms of common structures.
My Quesions : Are the electron transport systems and chemiosmosis simply ubiquitous phenomena in prokaryotes, or are these similarities evidence of highly conserved common ancestry? Or is there another answer? Is there any information regarding the phylogenetics of Rickettsiales and Cyanobacteria. Do these two organisms belong to a single small clade or were these biochemistries (ETCs, ATP Synthases, etc) ubiquitous at some point and have simply been preserved in these two organisms today?