Key-Notes: basic concepts in Developmental Biology
Key-Notes
5. Mosaic and Regulative development
As we have seen from the previous paragraph cytoplasmic determinants and inductive signals can both be used to control cell fate during development. If development was exclusively controlled by cytoplasmic determinants, the fate of every cell would depend uniquely on its lineage, while its position in the embryo would be irrelevant. This is the definition of mosaic development. On the other hand, if development was controlled exclusively by inductive signals, the fate of every cell would depend mostly on its position in the embryo. This is the definition of regulative development. The development of most organisms involves a combination of both mechanisms.
In mosaic development: Cell Fate = Cell Potency. The fate of the cell is governed entirely by its intrinsic characteristics, i.e. cytoplasmic determinants it inherits at cell division. During development each cell is said to undergo autonomous specification. If the cell is removed from the embryo it should, in principle, develop according to its intrinsic instructions and differentiate into the appropriate part of the embryo even if the rest of the embryo is not there.
In regulative development :Cell Potency is greater than Cell Fate. The fate of the cell is governed by its interactions with other cells. Each cell is said to undergo conditional specification. If the cell is removed from the embryo it should not fulfill its normal fate because it lacks the necessary interactions.
You can read more informations on mosaic and regulative development on the book chapter "The developmental mechanics of cell specification"