CRISPR/Cas9 screening using unique molecular identifiers

Loss of function screening by CRISPR/Cas9 gene knockout with pooled, lentiviral guide libraries is a widely applicable method for systematic identification of genes contributing to diverse cellular phenotypes. Here, we incorporate random sequence labels (RSLs) into the guides, which are used to independently track individual virus-transduced cell lineages or small pools of such lineages during the screen. RSL-guides function as internal replicates or as unique molecular identifiers and increase statistical power for robust and reproducible hit calling.