Stochastic switching of one cell in a clonal population in the same environment triggered by transcription errors. The growth of a single bacteria forming a microcolony was followed in a microfluidics flow chamber by time-lapse microscopy. The bright field frames are on the left, the GFP fluorescence frames are on the right and begin after the microcolony has become well established. The cell outlined in yellow is the cell that will change phenotype from lac OFF to ON, and the descendants of that cell will also manifest the ON phenotype. This video was created as part of the research for: Gordon AJ, Satory D, Halliday JA, Herman C. Heritable change caused by transient transcription errors. PLoS Genet. 2013 Jun;9(6):e1003595. doi: 10.1371/journal.pgen.1003595.