He reviews some of his previous work and presents an alternative to the dominant ‘Ancient RNA world’ hypothesis.
In terms of the genome organization of LUCA (Line 105), there are numerous arguments in favor of an RNA ancestral genome and the late unfolding of DNA as genetic repository (perhaps through viruses). I cannot understand how 2'-hydroxy groups could destabilize the molecule and lead to “intramolecular self-destruction” (Line 107). RNA has the wonderful property of folding in search of energetic and kinetic minima. These processes make use of a frustrated landscape, which is powerful in terms of its biological potential (stability, function, information). It is much more versatile than the rigid DNA alternative, which is enriched in the ‘information’ capacity. None of them have “self destruction” properties, which would have been weeded out by selection and self-organization very early in “chemical” evolution. In turn, everything about LUCA should be considered quite modern and far away from an initial FeS world. I refer to the work of Daniel Lundin and colleagues in Sweden about the rather late rise of some structures of the ribonuceotide reductase enzymes needed to built the DNA polymers. The Maurel theorem stands if one thinks of single genome molecules. But what if there were many short RNA genomes, as anticipated by Woese, each perhaps linked to different and ancient tRNA-like cofactors? As the author mentions, LUCA is contemporary to a rather complex biochemistry, with numerous structures harboring a multitude of active and allosteric sites in proteins, most of which drive central enzymatic functions.