Deciphering the ST.26 Sequence Format
For biotechnology patent applications that contain nucleotide and/or amino acid sequences, it is a requirement to submit a sequence listing that discloses the biological sequence data of the subject invention, which can then be entered into a publicly searchable database. The sequence listing may include a list of naturally occurring or synthetic nucleotides (RNA or DNA) and/or it may also contain amino acid protein sequences.
Having a standard against which nucleotide sequences are to be presented allows Applicants to prepare a single sequence listing in a patent application, which is then acceptable for use in both international and national or regional patent procedures.
Introducing the World Intellectual Property Organization (WIPO) ST.26 Standard
The ST.26 sequencing standard was implemented on 1 July 2022 to address some problems associated with use of the ST.25 format. This included some issues with respect to loss of data when the ST.25 sequence entered into public databases. There were also differences in the way the rules concerning ST.25 formatting were interpreted and enforced between IP Offices in different jurisdictions. As well as this, the ST.25 format is less structured, which makes it challenging for automated validation of the sequences presented in this format. Most importantly, the scientific standards of today are not accurately reflected by using the ST.25 format, since there has been an increase in the use of nucleotide analogs , D-amino acids, branched sequences amongst other variations, the information of which are not reflected in the ST.25 sequences presently available on public databases.
Since developing the ST.26 standard, processing of sequences presented in this format has been streamlined, which has greatly improved the ability of Patent Offices worldwide to automatically validate the data. The quality and clarity of the sequences are also improved, as further information is now provided on, for example, the different types of sequences disclosed (nucleotide analogs, D-amino acids and branched sequences). Several bioinformatic features have also been standardised, including where the feature keys, feature locations, qualifiers and qualifier values, as well as any sequence variants, are positioned.
WIPO ST.26 Standard Version 1.7
Most recently, effective from 1 July 2024, the newest WIPO ST.26 Standard now utilizes version 1.7, which has already been adopted by a number of Patent Offices, including the US Patent and Trade Mark Office (USPTO) and the European Patent Office (EPO). In this latest version, there has been some improvements to the consistency in use of technical terminology, for example, “3’-monophosphate” is now “5’-monophosphate”, which brings this closer in line with the standard nucleotide naming conventions. Further guidance is also given on how to present DNA sequences when the directionality of the sequence changes within the length of the strand, thus improving the way the sequence may be described. The latest version 1.7 is to be applied to applications filed on or after 1 July 2024, with version 1.6 still being applicable if for example, an international application was filed prior to this effective date, in which case version 1.6 or 1.7 applies.
In this short article series, we take a closer look into the changes introduced by the ST.26 standard since its implementation, when compared with the ST.25 standard. Specifically, our discussions will be split into several sub-categories: (i) changes to the general information section relevant for identifying the subject patent applications at hand, (ii) changes to the presentation of the sequence data itself and (iii) sequence annotations. Part (i) is discussed below.
(i) Differences in the General Information Section
The general information section contains bibliographic information about the patent application to which the sequence relates to.
With ST.26 sequences, only one Applicant and optionally, one inventor may be included, differing from the ST.25 format, which previously allowed all Applicants and inventor names to be included.
Similarly, ST.26 sequences only permit the inclusion of the earliest priority application, unlike with ST.25 sequence formats that allow the inclusion of all priority application information.
With respect to the title of the invention, ST.26 sequence files allow the application title to be included under one or more languages, an option that was previously not available under the ST.25 sequence standard.
ST.26 sequence files also allow the Applicant and/or inventor names to be presented using any valid Unicode character, provided that a transliteration or translation of this is provided. This again was not an option made available to the ST.25 sequence format.
Up Next
In our follow-up article, we will present a discussion on the differences between the presentation of sequence data under the ST.26 standard format. In the meantime, if you have any questions or would like some further advice on preparing sequence listings, please do not hesitate to contact our team at MBIP.
Featured image by WangXiNa on Freepik
