WIPO ST.26 Breakdown - Part III

As mentioned previously, the "Representation of Sequences" section goes into detail about the requirements and format of the sequence listing portion of the XML document therefore this section will be broken down into multiple posts.

As with WIPO ST.25, the first paragraph indicates that each sequence must be assigned a unique identifier. One noted difference is that unlike in ST.25 where a sequence could be identified as "residues 1-20 of SEQ ID NO: 1" (for example), this is no longer acceptable. All sequences require a unique number, regardless of if it is identical to a region of a longer sequence. As with ST.25, "000" placeholders are still acceptable if there is no sequence corresponding to an identifier.

Moving into nucleotide sequences, all sequences must be included in 5' to 3' direction or in the direction that mimics 5'-3' for modified molecules. Where a double stranded sequence is disclosed, either a single sequence or both sequences may be included assuming they are fully complementary, however, both must be included in 5'-3' orientation. If not fully complementary, both sequences must be included.

as with WIPO ST.25, the first nucleotide presented in a sequence is always position 1 except for sequences that are circular in which case the applicant may choose which nucleotide it wants designated as 1.

All nucleotides in a sequence must be represented using the following symbols (a, c, g, t, m, r, w, s, y, k, v, h, d, b, n) and be lowercase characters. You'll note that "u" is not an acceptable character for nucleotide sequences, therefore, unlike ST.25, all uracil residues in RNA molecules must be included as "t".  This is particularly important to remember if a Sequence Listing is being converted from ST.25 format to ST.26 as ST.25 sequences will have "u" characters within the RNA sequences.

The items above represent just a small portion of the requirements for nucleotide sequences. The section continues to describe modified nucleotides which will be discussed in the next post.

Again, if you have any questions, please reach out.