How should gaps in nucleotide sequences be represented in WIPO ST.25 format?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

According to MPEP 2423, gaps in nucleotide sequences should be represented using a specific symbol in WIPO ST.25 format:

“Gaps of indeterminate length in the sequence must be represented by a series of the lower case letter “n”, the number of “n” residues used in this manner must be set forth in numeric identifier .”

To properly represent gaps in nucleotide sequences:

• Use a series of lowercase “n” characters to indicate the gap
• Specify the number of “n” residues used in numeric identifier
• If the exact number of nucleotides in the gap is unknown, use a reasonable number of “n” characters to represent the gap

This standardized approach ensures clarity and consistency in sequence listings, allowing for accurate interpretation of gaps in nucleotide sequences.