In-depth analyses of piggyBac and Tol2 target sequence preferences in HEK 293. A. The sequence logos of piggyBac and Tol2 target sites. B. Two representative sequences flanking the sites repeatedly targeted by piggyBac. The TTAA tetranucleotide are underlined. C. A sequence alignment of four sequences on chromosome 16 that share 100% sequence identity with the first 100 bp of the piggyBac target B89-4. The residue that is different from the other three sequences at a given position is indicated in red. Dots represent all the primary sequences that are identical in all four sequences. The numbers on the top indicate the relative position of residues. D. The sequence logo of 184 sequences that share at less 97% sequence identity with the piggyBac target, B87-4. Note: The chromosomal sequence 5' and 3' to the target site are in lower cases and upper cases, respectively. piggyBac transposon is inserted at the position between -1 and +1.