Flowchart of the study method. (A) Paired diagnosis and relapse bulk samples were sorted by FACS, yielding a pure leukemic cell population apart from the normal fraction. (B) Single cells were sorted and whole genome amplification (WGA) was taken by a multiple displacement loop (MDA) procedure. (C1) The product of single-cell WGA entered the automatic lineage tree reconstruction module. (C2) Microsatellites (MSs; n = 120) were amplified by the laboratory robot for each single cell. (C3) Fluorescently labeled PCR products were analyzed by capillary electrophoresis. (C4) Automated analysis of capillary signals was translated to the number of MS repeat units and to reconstruct a lineage tree by phylogenetic methods (panel C was adapted from Frumkin et al¹² ).