Table 1 Comparison of L1 Retrotransposition hallmarks across TE types encoded by the L1 ORF2p. PPs consist of both germline (22) and somatic (1) PPs. Hallmarks of Retrotransposition include: insertion length (median length), the percentage of insertions with a detected polyA-tail, polyA-tail median length (bp), target site duplication or deletion (defined as 5–25 bp overlap or distance between insert flanking sequences on the reference), EN cut site (TTTT/A, TTTT/G, TTTC/A) and twin priming events

From: Structural features of somatic and germline retrotransposition events in humans