With the onset of full-scale DNA sequencing projects, biologists began to
look at organisms in an entirely new way. In contrast to last century’s paradigm,
genes are not the be-all and end-all of investigations into the workings of life.
Sequencing is just the first step in understanding organisms at a molecular
level; most of the questions remain unanswered. To really get at the function of
genes, biological systems must be analyzed at multiple levels of control—
external parameters (environment, developmental stage, molecular signals, etc.)
and internal parameters (transcription and mRNA degradation, posttranslational
modification, protein dynamics, and metabolite concentrations and fluxes).