Cell differentiation and potency

The developmental potential, or potency, of a cell describes the range of different cell types it CAN become. The zygote and its very early descendents are totipotent - these cells have the potential to develop into a complete organism. Totipotency is common in plants, but is uncommon in animals after the 2-4 cell stage. As development proceeds, the developmental potential of individual cells decreases until their fate is determined.