Spontaneous loss of tpzGFP-marked survival plasmid in Clone 12 cells. Cells were maintained in 96-well plates over the entire time period of the experiment (rectangles) or grown by continuous passaging in 90-mm petri dishes (triangles). Passaged cells were trypsinized and seeded into microplates on the day of reading. Plates were read using a microplate fluorescence reader. Data points show the mean relative fluorescence ratio between tpzGFP and sphGFP, expressed as a percentage of the same ratio measured from cells maintained under hygromycin B selection. All data represent the mean of fluorescence reading from at least three wells.
