Flux an important, but neglected, component of functional genomics.

Genomics approaches aimed at understanding metabolism currently tend to involve mainly expression profiling, although proteomics and steady-state metabolite profiling are increasingly being carried out as alternative strategies. These approaches provide rich information on the inventory of the cell. It is, however, of growing importance that such approaches are augmented by sophisticated integrative analyses and a higher-level understanding of cellular dynamics to provide insights into mechanisms that underlie biological processes. We argue the need for, and discuss theoretical and practical aspects of, the determination of metabolic flux as a component of functional genomics.