An example from Biology: Staying Active This Week in Science 29 October 1999
Early in fruit fly development, a cascade of transcription factors functions to direct transient homeotic gene expression for development of structures such as the leg or antenna. The established regulation, be it activation or repression, is then maintained by trithorax or polycomb group proteins, respectively. This regulatory state can be maintained through cell division. Caville and Paro (p. 955) now report that the mechanism of inheritance for the activated stage is through the acetylated histone H4, an active chromatin state, and not simply through the removal of a repressor molecule.
I look forward to the time when RSADT/AUT multi-modeling capability is fully available (and has been practiced and accepted by biological professionals as a teaching/reviewing exposition medium) to allow such a story to be modeled: first a sketch of cell division, itself, then the activation or repression regulation context, and finally, the old <removal of a repressor> versus <new active chromatin state> making visible the hidden subtlties — all shown to just the right level of detail by a concise supported-call network of shallow SA models. An accompanying Structured Analysis Text would weave through the story in more contextual detail, with instructive observations that make use of side branches of the SA arrow structuring, etc. [NEVER DESCRIBE, is the mantra, for description would merely duplicate or confuse what already is more clearly shown in the graphic, graphical modeling!]