The guide library v1 oligos were cloned into an sgRNA expression vector and barcodes were subsequently added by cloning random oligonucleotides. Note that the barcode assignments here are specific to this plasmid library and they are entirely arbitrary, as they result from random events that occurred during this cloning reaction. They don’t reflect a designed property of the guide oligos.
The barcode_v1_181005/grna-assign-barcode-grna-good.txt table
associates barcodes with guide RNAs. Certain barcodes are associated
with Empty guide RNA expression constructs that are not expected to
produce functional sgRNAs. These arise at low frequency due to the
guide cloning reaction and we typically treat them as internal
negative controls.