How are modified bases represented in nucleotide sequence listings?

According to MPEP 2422, modified bases in nucleotide sequence listings can be represented as follows:

1. The modified base can be represented as the corresponding unmodified base in the sequence itself.
2. The modification must be further described in numeric identifier of the Feature section of the “Sequence Listing”.
3. Specific symbols for modified bases may be used in the description or Feature section, but not in the sequence itself.

The MPEP states: “Modified bases may be represented as the corresponding unmodified bases in the sequence itself, if the modification is further described in numeric identifier of the Feature section of the “Sequence Listing”.“

For modifications not listed in Appendix B of WIPO ST.25, the full chemical name should be used to describe the modification in the Feature section.

To learn more:

• modified bases
• nucleotide sequences
• sequence listing
• WIPO ST.25
• patent applications