Abstract: We describe methods and compositions for setting and maintaining the state of gene expression in a cell. The genetic circuit clocked latch has two states with each state corresponding to a different pattern of gene expression. The genetic circuit clocked latch allows one to set the state of the latch only when the clock signal is active. When the clock signal is inactive, the state of the latch is maintained as the state when the clock signal was last active. The clocked latch consists of gating circuitry and a bistable switch. The circuit is implemented as nucleic acid constructs. By analogy with a similar circuit found in digital electronics, such a circuit is expected to have an increased immunity to input fluctuations and is expected to facilitate the design of large circuits composed of multiple latches.