Mixing normal donor and monosomy 7 patient cells. Mononuclear cells from an MDS patient with monosomy 7 and from a normal donor were analyzed with IC Flow-FISH independently (without mixing) and after mixing in differing proportions. From flow cytometry data, histograms of chromosome 7 probe fluorescence values were prepared for unmixed patient (A) and unmixed donor (B) monocyte populations. (C-D) Samples having mixtures of patient and donor mononuclear cells, with 5% patient cells expected in panel C and 10% patient cells expected in panel D. Monocytes (cells corresponding to gated regions in scatter plots) were selected, and histograms of monocyte probe fluorescence were prepared as in panels A and B. Proportions of each population were found by applying a 2-component Gaussian mixture model, and the fitted normal curves shown on histograms were generated from the mixture model results. The monosomy 7 populations (lower-binding populations; red normal curve in histograms) were found to represent 21.0% (C) and 38.2% (D) of monocytes.