Mean Length of the 3′ “A-Tail” of Different Alu and L1 Elements
| Repeated element group | Total analyzed | Length A-tail[i] |
| Alu J and S | 100 | 21 ± 8 |
| Alu Yb8 | 79 | 28 ± 9 |
| Alu Ya5 | 235 | 26 ± 9 |
| Alu Ya5a2 | 23 | 30 ± 11 |
| Alu “disease”[ii] | 16 | 58 ± 19 |
| L1 Ta | 50 | 41 ± 20 |
| L1 “disease”[ii] [iii] | 14 | 77 ± 33 |
[i] Mean ± standard deviation.
[ii] Elements found to cause disease by insertion.
[iii] Includes some elements that were generated as new inserts from the L1 tissue culture assay and two L1 elements causing disease in mice.