RNA editing and modifications of RNAs might have favoured the evolution of the triplet genetic code from an ennuplet code

- For the origin of the genetic code we consider credible the transition from ennuplet codes to the triplet code.
- We maintain that an extensive modification of RNAs has been crucial for this transition.
- RNA editing and post-transcriptional modifications of RNAs are retained vestiges of these modifications and of this transition.
- Trans-translation and ribosomal frameshifting are also considered by this hypothesis.

Here we suggest that the origin of the genetic code, that is to say, the birth of first mRNAs has been triggered by means of a widespread modification of all RNAs (proto-mRNAs and proto-tRNAs), as today observed in the RNA editing and in post-transcriptional modifications of RNAs, which are considered as fossils of this evolutionary stage of the genetic code origin. We consider also that other mechanisms, such as the trans-translation and ribosome frameshifting, could have favoured the transition from an ennuplet code to a triplet code. Therefore, according to our hypothesis all these mechanisms would be reflexive of this period of the evolutionary history of the genetic code.