Characteristics of NotI and AscI Restriction Sites
| NotI | AscI | |
| Total number of restriction sites in the human genome[i] | 9628 | 4935 |
| Number of restriction sites in CpG islands | 8239 (86%) | 4071 (83%) |
| Number of restriction sites in repetitive elements, not CpG islands | 520 (5%) | 332 (7%) |
| Frequency of restriction sites near 5′ end of a known gene | 3357 (34.9%) | 1612 (32.7%) |
| Frequency of restriction sites near 3′ end of a known gene | 1328 (13.8%) | 725 (15%) |
| Frequency of restriction sites inside a gene | 1392 (14.5%) | 738 (15%) |
| Frequency of restriction sites falling near ESTs | 2.221 (23.1%) | 1001 (20.3%) |
| Frequency of CpG islands with both NotI and AscI sites | 1100 (3.7%) | |
[i] August 6, 2001 draft assembly of UCSC.