Inheritance and state switching of genetic toggle switch in different culture growth phases

Using the gene engineering methods, one can construct simple artificial gene networks with two stable functioning regimes (bistable genetic systems). Such genetic systems make it possible for cells with identical genotype to inherit two alternative phenotypes. The toggle switch is just one of the types of bistable genetic systems. In this work, we investigate the inheritance and switching of toggle switch functioning regimes in the cells at different culture growth phases. It is shown that during transition into the stationary growth phase the inheritance of stable states is disturbed and variations in the toggle-switching rate are more possible in different cells. Also, simultaneous expression of two genes of the system has been experimentally modelled. According to our results, the culture growth phase in this period determines later on the ratio between cell phenotypes in a population.