Fig. 6.

Optogenetic control of constitutive gene expression. (A) Regularly repeated short light pulses (shown at the bottom) lead to a slow steady increase in the differentiated population fraction while the differentiated fraction increases fairly quickly in response to continuous light. (B) Over intermediate time periods, repeated selective differentiation and reversion to the mean balance each other, which leads to approximately constant EL222:mVenus medians in all cases. (C) After transient dynamics in response to the start of the light sequence, EL222:mVenus distributions in undifferentiated cells reach a quasi-stationary form that remains invariant for extended time periods (see also SI Appendix, Fig. S13). Color coding of distributions labels corresponds to the light sequences and data in A and B.