Fig. 1

Flow cytometry of RGB-marked iPS cell lines at early passage and 37–38 passages after transduction. Left to right: green plotted against blue channel, green against red and blue against red. MOI 25 used for RGB marking. a C25-young cells at passage 8. Homogeneous distribution of dots within dot plots without any distinguishable clones indicates a polyclonal state. b C25-old cells at passage 6. A polyclonal state can be observed. c BJ cells at passage 6. A polyclonal state can be observed. d C25-young cells 37 passages after RGB marking. Oblique lines in top-right quadrant indicate presence of only a few clones. e C25-old cells 37 passages after RGB marking. Two clones have overtaken almost the entire culture, representing 95% total cells. f BJ cells 38 passages after RGB marking. Yellow clone represents 90% of cells, while rest mostly represented by four clones. Arrowhead points out one streak representing a single-coloured minor clone. BFP blue fluorescent protein, p passage, Q quadrant