The virtual human: towards a global systems biology of multiscale, distributed biochemical network models.

There is an emerging recognition of the importance of modelling large-scale biochemical systems, with the 'digital human' an obviously desirable goal. This will then permit researchers to analyse the behaviour of such systems in silico so as to be able to perform 'what-if?' experiments prior to determining whether they are actually worthwhile or not, and for understanding whether a particular model does in fact describe or predict experimental observations. Existing and developing standards such as SBML are beginning to permit the principled storage and exchange of biochemical network models, while environments for effecting distributed workflows (such as Taverna) will allow us to link together these models and their behaviour. This allows the local experts to work on those parts of cellular or organellar biochemistry on which they have most expertise, while making their results available to the community as a whole. This kind of architecture permits the distributed yet integrated goal of an evolving 'digital human' model to be realized.