Abstract: A method of screening is provided including providing a combination of a plurality of proliferating cell types wherein each proliferating cell type has a unique associated barcode within its genome that is different from other proliferating cell types of the plurality and wherein each proliferating cell type includes an exogenous gene that when expressed produces an associated phenotype to the proliferating cell type which alters proliferation of the cell type, introducing a perturbation to one or more of the plurality of proliferating cell types, inducing expression of one or more of the exogenous genes, determining the relative number of unique associated barcodes after a period of proliferation, and comparing the relative number of unique associated barcodes to a control relative number of unique associated barcodes to indicate the effect of the perturbation on the one or more of the plurality of proliferating cell types.