Fig 8 is very reminiscent of Fig 1 of Wu and Higgs (2009) J Mol Evol 69:541-554 and Fig 1 of Wu and Higgs (2011) Astrobiology 11:895-906.
If there were two genes, what were the functions of the two genes? The connection between the reactions catalyzed by the ribozymes and the concepts of CCSI and CMIO is not very clear at this point.