“…Every possible roadblock requires an additional ad hoc hypothesis to explain it, which together with dubious auxiliary assumptions (onion ribosomal growth, unbudgeted helix growth, and many other “ external indicators of relative age” ), weaken their theory of ribosomal history. Recently, we examined putative IFs in small and large rRNA subunits (Caetano-Anollés, 2015; Caetano-Anollés and Caetano-Anollés, 2015a,b). We showed concerning “reversals,” incorrect branch-to trunk assignments, none of which Petrov et al (2014, 2015) explain.…”