<p>L1Hs libraries were prepared as previously described, except that the 454 primers A and B were used instead of Illumina adapters and that high throughput sequencing was performed by using the primer A instead of the primer B, thus allowing the detection of the polyA (pA) sequence followed by the sequence of the new locus of insertion. The sequences were then processed for mapping on the genome to detect reference as well as non-reference L1Hs insertions. L1Hs reference insertion sequences would match the reference genome from their 3′UTR sequence to the end of their flanking sequence in one location only while non-reference insertion sequences will have their 3′UTR sequence and flanking sequence match the genome on two distinct locations.</p
