6.2.2 Sequences comprising residues that are not specifically defined (n or X) 

If an enumerated sequence comprises regions of specifically defined residues separated by one or more gaps of n or X, i.e. residues that are not specifically defined, the representation of this sequence in the sequence listing depends on whether the exact number of n or X residues is known (see WIPO Standard ST.26, paragraph 36) or unknown (see WIPO Standard ST.26, paragraph 37).

For example, considering that the following sequence is enumerated in the application:

a10nxt12

if the number of "n" residues is known, e.g. x=2, the sequence should be represented as a single SEQ ID (if it also meets the minimal length requirement as defined in paragraph 7 or ST.26 and in F‑II, 6.2.1) as follows:

aaaaaaaaaanntttttttttttt

If the number of "n" residues is unknown, each region of specifically defined residues that meets the minimal length requirement in paragraph 7 of WIPO Standard ST.26 must be included in the sequence listing as a separate SEQ ID.

For example, for the sequence: a10nxt12

the sequence listing must have two entries

SEQ ID No. 1: aaaaaaaaaa

SEQ ID No. 2: tttttttttttt

The sequences should be annotated to indicate that they are part of the same molecule and separated by an undefined number of "n" residues (see example 37-2 of Annex VI of WIPO Standard ST.26).

If a range is disclosed, e.g. x= 5-10 nucleotides, the sequence should be represented as a single SEQ ID comprising 5 n or 10 n (see example 36-3 of Annex VI of WIPO Standard ST.26).

In the above example, the sequence must either comprise 5 n or 10 n. In both cases, the SEQ ID must be annotated with a "note" qualifier. In cases where the sequence comprises 5 n, the note should indicate that up to 5 n can be added. In cases where the sequence comprises 10 n, the note should indicate that up to 5 n can be deleted. The appropriate feature key must be associated with the "note" qualifier describing the variant. See paragraph 96 of WIPO Standard ST.26 and F‑II, 6.2.3 for information on selecting the correct feature key.

Alternatively, if a range is disclosed, e.g. x= 5-10 nucleotides, all possible variants may be represented independently, i.e. as separate SEQ IDs.