"...Scientists at the Whitehead Institute in Cambridge, Mass., have developed a technique for uncovering the interactions of transcription factors. These are the agents that switch genes on or off in the cell. By figuring out these interactions on a genomewide scale, they have reconstructed the top level of the controls that govern a human embryonic stem cell.This is a moderately high level discussion of the complexity of developmental biology. If you want an even more arcane discussion, go find the journal article on which this story is based. The journal Cell should be available in any university library.
The discovery is a starting point for addressing the next question, that of how an embryonic stem cell commits itself to a specific fate, like becoming a cell of the brain or liver or pancreas gland...."
Suffice it to say that the developmental sequence is incredibly complex, and that there are no easy answers. Such research is a necessary step for further resesarch in getting stem cells to take a particular path, say, in the repair of damaged organs or the alleviation of genetic diseases.