Comparative genomics is a general approach for understanding how genomes differ, which can be considered from many angles. For instance, this approach can delineate how gene content varies across organisms, which can lead to novel hypotheses regarding what those organisms do. It also enables investigations into the sequence-level divergence of orthologous DNA, which can provide insight into how evolutionary forces differentially shape genome content and structure across lineages.
Such comparisons are often restricted to protein-coding genes, as these are sensible units for assessing putative function and for identifying homologous matches in divergent genomes. Although information is lost by focusing only on the protein-coding portion of genomes, this simplifies analyses and has led to crucial findings in recent years. Perhaps most dramatically, analyses based on hundreds of orthologous proteins across microbial eukaryotes are fundamentally changing our understanding of the eukaryotic tree of life (Burki et al. 2020).
These and other topics are highlighted in a new pre-print from Dr. Daniel Richter and colleagues, which describes EukProt (Richter et al. 2022): a database containing protein sets from 993 eukaryotic species. The authors provide a BLAST portal for matching custom sequences against this database (https://evocellbio.com/eukprot/) and the entire database is available for download (https://doi.org/10.6084/m9.figshare.12417881.v3). They also provide a subset of their overall dataset, ‘The Comparative Set’, which contains only high-quality proteomes and is meant to maximize phylogenetic diversity.
There are two major advantages of EukProt:
1. It will enable researchers to quickly compare proteomes and perform phylogenomic analyses, without needing the skills or the time commitment to aggregate and process these data. The authors make it clear that acquiring the raw protein sets was non-trivial, as they were distributed across a wide variety of online repositories (some of which are no longer accessible!).
2. Analyses based on this database will be more reproducible and easily compared across studies than those based on custom-made databases for individual studies. This is because the EukProt authors followed FAIR principles (Wilkinson et al. 2016) when building their database, which is a set of guidelines for enhancing data reusability. So, for instance, each proteome has a unique identifier in EukProt, and all species are annotated in a unified taxonomic framework, which will aid in standardizing comparisons across studies.
The authors make it clear that there is still work to be done. For example, there is an uneven representation of proteomes across different eukaryotic lineages, which can only be addressed by further characterization of poorly studied lineages. In addition, the authors note that it would ultimately be best for the EukProt database to be integrated into an existing large-scale repository, like NCBI, which would help ensure that important eukaryotic diversity was not ignored. Nonetheless, EukProt represents an excellent example of how reproducible bioinformatics resources should be designed and should prove to be an extremely useful resource for the field.
Burki F, Roger AJ, Brown MW, Simpson AGB (2020) The New Tree of Eukaryotes. Trends in Ecology & Evolution, 35, 43–55. https://doi.org/10.1016/j.tree.2019.08.008
Richter DJ, Berney C, Strassert JFH, Poh Y-P, Herman EK, Muñoz-Gómez SA, Wideman JG, Burki F, Vargas C de (2022) EukProt: A database of genome-scale predicted proteins across the diversity of eukaryotes. bioRxiv, 2020.06.30.180687, ver. 5 peer-reviewed and recommended by Peer Community in Genomics. https://doi.org/10.1101/2020.06.30.180687
Wilkinson MD, Dumontier M, Aalbersberg IjJ, Appleton G, Axton M, Baak A, Blomberg N, Boiten J-W, da Silva Santos LB, Bourne PE, Bouwman J, Brookes AJ, Clark T, Crosas M, Dillo I, Dumon O, Edmunds S, Evelo CT, Finkers R, Gonzalez-Beltran A, Gray AJG, Groth P, Goble C, Grethe JS, Heringa J, ’t Hoen PAC, Hooft R, Kuhn T, Kok R, Kok J, Lusher SJ, Martone ME, Mons A, Packer AL, Persson B, Rocca-Serra P, Roos M, van Schaik R, Sansone S-A, Schultes E, Sengstag T, Slater T, Strawn G, Swertz MA, Thompson M, van der Lei J, van Mulligen E, Velterop J, Waagmeester A, Wittenburg P, Wolstencroft K, Zhao J, Mons B (2016) The FAIR Guiding Principles for scientific data management and stewardship. Scientific Data, 3, 160018. https://doi.org/10.1038/sdata.2016.18
DOI or URL of the preprint: https://doi.org/10.1101/2020.06.30.180687
Version of the preprint: 3
To Dr. Richter and colleagues,
I think your changes have addressed most of the reviewer’s comments (except for one minor comment – see below) and I think the manuscript is in excellent condition, and requires only a small tweak prior to recommendation.
One important thing to note is that I received a “timed out” error when trying to load http://evocellbio.com/eukprot/ - I’m guessing this was just a transient problem, but should be checked.
The minor comment that I think the authors perhaps missed was this partial statement from reviewer 1:
“…mention the fact that they cannot technically evaluate the tools and parameters selection for the de novo transcriptome assembly paragraphs (lines 300-306) and the automated genome annotation (lines 329-338)”
Those line numbers no longer match, but the sections correspond to the paragraphs starting with “‘assemble mRNA’: de novotranscriptome assembly “ and “‘predict genes’: we used EukMetaSanity”, respectively. I think either a little more explanation of why these parameters were chosen (e.g., why stating why using the same parameters as Alexander et al. 2021 makes sense, in the case of the predict genes). If the options are somewhat arbitrary, which might be the case with the assembly and filtering options, then the authors could mention that these options were not evaluated but are similar to what are commonly used, which I believe would address the reviewer’s point.
Last, I recommend two very minor changes:
In your title, I recommend that you change “a database” after the “Eukprot:” to be “A database”. I believe that most style guides suggest the latter format, but the former is widespread in the scientific literature so I leave that choice to you.
I do however strongly think that the link to the webserver should be added to the abstract, which I think many readers comes to expect when reading about bioinformatics resource.
Once these last changes are addressed I would be pleased to recommend your article.
All the best,
DOI or URL of the preprint: https://doi.org/10.1101/2020.06.30.180687
Version of the preprint: 1
Two reviewers have completed their assessments and have determined that the manuscript is sound and describes a useful resource for the field. They have requested only minor revisions.
I share their enthusiasm for this resource and look forward to seeing the next draft of this manuscript.
I concur with reviewer #2 that more detailed discussion regarding how their resource differs from PhyloDB is needed. I also did not find Table 1 very informative, and I would think a supplementary table listing the actual URLs used would be more relevant to interested readers. But since the reviewers did not take issue with the table, I will not require it to be changed, and leave the decision to the authors’ preference.
Given the small changes requested, the authors should aim to format their manuscript for according to PCI Genomics guidelines (see: https://genomics.peercommunityin.org/help/guide_for_authors#h_3273113785671619705234847)
Formatting issues that I noticed are
- Table and Figure should be embedded within the text.
- An email for the corresponding author should be indicated
- Rather than a database availability statement, this should be moved to the end of the abstract (for the link to the database webserver), and also mentioned in the “Data, script and code availability” section at the end of the manuscript.
- I believe moving all of the descriptions of the database to a “Results and Discussion” heading would be most appropriate for this article type (and the current headings, such as “The EukProt Database” changed to sub-headings). Based on the formatting guidelines, PCI Genomics strongly recommends separate Results and Discussion headers, but I think a combined section would be acceptable in this case, as the manuscript is very clear as it is.
- The methods section should be moved before the Results section
- Please re-format the acknowledgements section to match the recommended format. Also, is the lower-case “i” in Núria Ros i Rocher a typo? I think this is supposed to be a hyphen.
- Please add a Data, script, and code availability section at the end. Note that the authors’ custom code must also be made available in this section.
- Make in-text citations square brackets when they are within parenthetic phrases (e.g., “Eisen, 2003” at L48.