in vitro selection data
See Supplementary Algorithms/Sequence Binning for more information.  Post-selection barcodes (first four bases of read) [no barcode = 1000 nM sgRNA v1.0 AACA = 100 nM sgRNA v2.1 TTCA = 1000 nM sgRNA v2.1].  Pre-selection constant sequence = ACCTACCTGCCGAG.  Post-selection constant sequence = CTCGGCAGGT.  Selection barcodes [CLTA1 = TGTGTTTGTGTT, CLTA2 = AGAAGAAGAAGA, CLTA3 = TTCTCTTTCTCT, CLTA4 = ACACAAACACAA for post-selection; reverse complements of these selection barcodes for pre-selection]