by Chet Raymo
It all started out as a single fertilized cell. 2. 4. 8. 16. 32. Eventually, tens of trillions of cells. How do the cells multiplying in my left hand know what the cells in my right hand are doing? How is such perfect symmetry maintained across what is in effect molecular light-years?
Genes, of course. Those little satchels of info carried along by every cell, copied with amazing robustness at each division. Chet's handprint. But to say that says very little. Back in June the journal Science had a special section on morphogenesis in the developing organism. The most common word was "mystery."