CaTCH is a functional lineage tracing tool using genetic barcodes to label and follow million of cell clones in a selection experiment. Furthermore, CaTCH allows to isolate specific cell clones from heterogeneous populations by their barcode. Thus, founding clones of a phenotype of interest can be retrospectively isolated alive using FACS (fluorescence-activated cell sorting), allowing to perform functional experiments. Example applications of this method are investigating the evolutionary selection of resistance to therapies or other evolutionary pressures.