The Ribosome as a Missing Link in Prebiotic Evolution III: Over-Representation of tRNA- and rRNA-Like Sequences and Plieofunctionality of Ribosome-Related Molecules Argues for the Evolution of Primitive Genomes from Ribosomal RNA Modules

Round 1

Reviewer 1 Report

This is an interesting manuscript,

I would like to suggest only the following revision. Authors have to tell us in a clear way why they are sure that RNA-like sequences are very ancient traits and not acquired traits.

After this revision, the manuscript could be accepted.

Author Response

"Authors have to tell us in a clear way why they are sure that RNA-like sequences are very ancient traits and not acquired traits." There are two possible interpretations of this request. One is to address the literal one of explaining why we think that "RNA-like sequences" are ancient and not acquired, which involves citing more of the well-known literature regarding an RNA-world origin of life. The other is that the reviewer is asking us to address how we know that ribosomal RNA, more specifically, is an ancient molecule predating cells rather than a derived set of molecules that evolved with or after cellular life. We have now addressed both possibilities in our Discussion section and provided additional citations both to the key RNA-world literature and to the many taxonomic studies that demonstrate that ribosomes evolved significantly prior to the first universal ancestors of modern cellular life.

Reviewer 2 Report

In this manuscript Root-Bernstein et. al., provide evidences to support their previously claimed "Ribosome-first" theory. To substantiate their claim they provide adequate literature and new data. Using both sources they show that, evolved genomes contain rRNA like sequences at significantly higher frequencies. These genes code for both non-ribosomal proteins and ribosomal proteins with extra-ribosomal functions. 

    Overall its a well written manuscript and it provides ample information for the "Ribosome-first" theory. 

Author Response

We thank the reviewer for her or his positive comments.