Theory 16/Hysteresis & Memory/Gene regulation
Gene Switches Hold Their State
The claim
Bistable genetic switches require a larger inducer concentration to flip than to hold, so the switching threshold depends on the direction of approach.
01Mechanism
Positive feedback creates two stable states; the barrier between them means the flip point differs for on-to-off and off-to-on transitions.
02Prediction
Flip thresholds should differ by direction.
03Refutation
Symmetric thresholds would remove the hysteresis.