New Changes Coming to Sequence Listings in Patent Applications

Modernization of sequence listing requirements will come into force on July 1, 2022. These changes are part of the Rules Amending the Patent Rules, which introduce excess claims fees and continued examination provisions, that will come into force on October 3, 2022. More information regarding our strategy around Canada’s new prosecution procedures and fees can be found here.

A sequence listing includes descriptive information about each sequence known as annotations for each nucleotide and/or amino acid sequence disclosed in a patent application, allowing the examiner to search databases for prior disclosures. The new sequence listing Rules will require all international and national patent applications having a filing date on or after July 1, 2022, to comply with WIPO’s new sequence listing standard ST.26. The previous standard ST.25 dated from 2007 and no longer reflected sequence types that are common today. WIPO’s new sequence listing standard ST.26 allows more sequence data to be exchanged in electronic form and introduced into computerized databases of IP offices and International Nucleotide Sequence Database Collaboration databases, such as GenBank and EMBL-EBI. Accordingly, under the new Rules, sequence listings will be easier to prepare and file, thus potentially reducing costs for the applicant. These Rules will also make it easier to access and compare sequence listings between patent and scientific publications, thus potentially improving searches. Transitional provisions allow PCT and regular applications that have a filing date before July 1, 2022 to use sequence listings that comply with the current ST.25 standard. Accordingly, only new filings will be affected, where sequence listings will need to be updated to the ST.26 standard. More information on the differences between ST.25 and ST.26 can be found here. Most importantly, the new sequence listings must be submitted in XML (eXtensible Markup Language) format, instead of the previous ASCII .txt. Other notable changes include specifying D-amino acids, linear portions of branched sequences, and nucleotide analogs (e.g., PNAs and GNAs), excluding very short nucleotide or amino acid sequences, and representing amino acid sequences by single-letter codes. WIPO’s software for generating sequence listings in accordance with the new rules can be found here. It will be possible to correct, immediately after the filing, a sequence listing which is not yet in ST.26 standard, as long as no new matter is introduced, but our Team can help you to file the proper sequence listing at filing.

ROBIC has a deep bench of experienced patent prosecutors who can provide insight on potential strategies to maximize value for Canadian patent applications. Contact us at for assistance in navigating the changes brought by the new Patent Rules to your portfolio.