Adding informative metadata to bioinformatics services

Carole Goble and the other authors of “Data curation + process curation = data integration + science” have written a paper on the importance of curating not just the services used in bioinformatics, but also how they are used. Just as more and more biologists are becoming convinced of the importance of storing and annotating their data in a common format, so should bioinformaticians take a little of their own medicine and ensure that the services they produce and use are annotated properly. I personally feel that it is just as important to ensure that in silico work is properly curated as it is in the more traditional, wet-lab biological fields.

They mention a common feature of web services and workflows: namely, that they are generally badly documented. Just as the majority of programmers leave it until the last possible minute to comment their code (if they comment at all!), so also are many web services annotated very sparsely, and not necessarily in a way that is useful to either humans or computers. I remember that my first experience with C code was trying to take over a bunch of code written by a C genius, who had but one flaw: a complete lack of commenting. Yes, I learnt a lot about writing efficient C code from his files, but it took me many hours more than it would have done if there had been comments in there!

They touch briefly on how semantic web services (SWS) could help, e.g. using formats such as OWL-S and SAWSDL. I recently read an article in the Journal of Biomedical Informatics (Garcia-Sanchez et al. 2008, citation at the end of the paper) that had a good introduction to both semantic web services and, to a lesser extent, multi-agent systems that could autonomously interact with such services. While the Goble et al. paper did not go into as much detail as the Garcia-Sanchez paper did on this point, it was nice to learn a little more about what was going on in the bioinformatics word with respect to SWS.

Their summary of the pitfalls to be aware of due to the lack of curated processes was good, as was their review of currently-existing catalogues and workflow and WS aggregators. The term “Web 2.0” was used, in my opinion correctly, but I was once again left with the feeling that I haven’t seen a good definition of what Web 2.0 is. I must hear it talked about every day, and haven’t come across any better definition than Tim O’Reilly’s. Does anyone reading this want to share their “favorite” definition? This isn’t a failing of this paper – more of my own lack of understanding. It’s a bit like trying to define “gene” (this is my favorite) or “systems biology” succinctly and in a way that pleases most people – it’s a very difficult undertaking! Another thing I would have liked to have seen in this paper, but which probably wasn’t suitable for the granularity level at which this paper was written, is a description and short analysis of the traffic and usage stats for myExperiment. Not a big deal – I’m just curious.

As with anything in standards development, even though there are proposed minimal information guidelines for web services out there (see MIAOWS), the main problem will always be lack of uptake and getting a critical mass (also important in community curation efforts, by the way). In my opinion, a more important consideration for this point is that getting a MIA* guideline to be followed does not guarantee any standard format. All it guarantees is a minimal amount of information to be provided.

They announce the BioCatalogue in the discussion section of this paper, which seems to be a welcome addition to the attempts to get people to annotate and curate their services in a standard way, and store them in a single location. It isn’t up and running yet, but is described in the paper as a web interface to more easily allow people to annotate their WSDL files, whereas previous efforts have mainly focused on the registry aspects. Further information can be associated with these files once they are uploaded to the website. However, I do have some questions about this service. What format is the further information (ontology terms, mappings) stored in? Are the ontology terms somehow put back into the WSDL file? How will information about the running of a WS or workflow be stored, if at all? Does it use a SWS format? I would like to see performances of Bioinformatics workflows stored publicly, just as performances of biological workflows (eg running a microarray experiment) can be. But I suppose many of these questions would be answered once BioCatalogue is in a state suitable for publishing on its own.

In keeping with this idea of storing the applications of in silico protocols and software in a standard format, I’d like to mention one syntax standard that might be of use in storing both descriptions of services and their implementation in specific in silico experiments: FuGE. While it does not currently have the structures required to implement everything mentioned in this paper (such as operational capability and usage/popularity scores) in a completely explicit way, many of the other metadata items that this paper suggests can already be stored within the FuGE object model (e.g. provenance, curation provenance, and functional capability). Further, FuGE is built as a model that can easily be extended. There is no reason why we cannot, for example, build a variety of Web services protocols and software within the FuGE structure. One downside of this method would be that information would be stored in the FuGE objects (e.g. a FuGE database or XML file) and not in the WSDL or Taverna workflow file. Further, there is no way to “execute” FuGE XML files, as there is with taverna files or WSs. However, if your in silico experiment is stored in FuGE, you immediately have your computational data stored in a format that can also store all of the wet-lab information, protocols, and applications of the protocols. The integration of your analyses with your wet-lab metadata would be immediate.

In conclusion, this paper presents a summary of a vital area of bioinformatics research: how, in order to aid data integration, it is imperative that we annotate not just wet-lab data and how they were generated, but also our in silico data and how they were generated. Imagine storing your web services in BioCatalogue and then sharing your entire experimental workflows, data and metadata with other bioinformaticians quickly and easily (perhaps using FuGE to integrate in silico analyses with wet-lab metadata, producing a full experimental metadata file that stores all the work of an experiment from test tube to final analysis).

Goble C, Stevens R, Hull D, Wolstencroft K, Lopez R. (2008). Data curation + process curation=data integration + science. Briefings in bioinformatics DOI: 19060304

F GARCIASANCHEZ, J FERNANDEZBREIS, R VALENCIAGARCIA, J GOMEZ, R MARTINEZBEJAR (2008). Combining Semantic Web technologies with Multi-Agent Systems for integrated access to biological resources Journal of Biomedical Informatics, 41 (5), 848-859 DOI: 10.1016/j.jbi.2008.05.007


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