I have now finished reviewing the manuscript entitled “Comparative analysis of the superoxide dismutase (SOD) gene family in Cetartiodactyla”. I was positively impressed by the quality and quantity of information the authors were able to dissect towards, essentially, a meta-analysis on publicly available genome data. The writing is captivating, and the figures are both appealing and easy to understand. My main criticism to this is work is that, despite all the effort in making it clear for specialized peers to understand it, it reads” only” as a characterization of the gene family SOD and thus within an extremely specific focus on molecular evolution. While I understand and respect that perhaps this has been the sole purpose and motivation behind this work, its current form, is (in my opinion) undervaluing its scope and undermine the potential interest that others, aside experts in molecular evolution, could have in this work. Thus, I feel that the evolutionary context should be expanded to capture the attention of JEB´s broad readership.
Find below some potential suggestions to widen the scope of this excellent work, as well as some minor comments. Bear in mind I am not an expert in cetacean biology, and thus my suggestions might appear more general than they perhaps should.

1 – I wonder if the amino acid variation effect predictions could be understood as some sort of null model against which population screens of these genes could be run against?
2 – Are there any population screens on any of the SODs´ genetic diversity, on either cetaceans or other species, that could offer a guide to what one could expect regarding intra-specific diversity?
3 - Could a study of this kind contribute to the discovery of de novo genes or novel gene functions, for instances, by identifying lineage- or species-specific duplications? Such contextualization could broaden the scope of interest that the work deserves.

Some minor comments:
Lines 74-76: Please justify the rationale for these cut-offs.
Lines 98-102: What are the potential downsides of utilizing a human-based prediction tool of deleterious mutations and extrapolating to other species? How reliable are these predictions?
Line 195: remove “that”
Lines 216-217: In what context could the stability mentioned here be adaptive?
Lines 249-251: what would be the consequences of such instability? Could you develop on this topic?
Lines 320-321: In what evolutionary context could a synteny be conserved within a lineage?
Lines 322-323: Please clarify this sentence
Lines 327-329: Please explain what you mean with “adaptive significance in the adaptation to diving”

I have now reviewed the new version of the article "Comparative analysis of the superoxide dismutase (SOD) gene family in Cetartiodactyla" and I find it improved to the point of accepting for publication. I once again would like to congratulate the authors for this work.