Cellecta provides kits for labeling all cells in a particular population with a specific, single barcode. The barcode constructs are selectable by puromycin and–depending on which kit you choose–an optional red fluorescent protein (RFP) marker so cells containing barcodes will fluoresce red. Each barcode construct is designed so that the barcode can be differentiated by sequencing as well as by PCR and qPCR using barcode-specific primers. In addition to having a unique sequence, each contains common, universal primer-binding sites to enable amplification of the differently sized products so populations labeled with a specific barcode can be identified on an agarose gel or analyzer. Further, each barcode has a unique qPCR probe sequence that enables differential amplification and quantitation using qPCR. Each kit contains 1 x 10^7 TU of each of 4 individual pre-packaged lentiviral barcode constructs, enough to label millions of cells. The barcode constructs in this kit are selectable by puromycin and do not have a red fluorescent protein (RFP) marker. Kits are also available with barcode constructs that have an additional RFP marker. The progeny from each cell population can be sampled after differently labeled populations are co-cultured or otherwise grown together.