Which nucleotides are considered “specifically defined” according to WIPO Standard ST.26?

According to MPEP 2412.03(a), WIPO Standard ST.26 defines “specifically defined” nucleotides as any nucleotide other than those represented by the symbol “n”. The MPEP provides a table of nucleotide symbols, where:

• Symbols a, c, g, and t/u represent specifically defined nucleotides
• Symbols like m, r, w, s, y, k, v, h, d, and b represent combinations of specifically defined nucleotides
• The symbol n represents “unknown” or “other” and is not considered specifically defined

This definition is crucial for patent applications filed on or after July 1, 2022, containing nucleotide sequence disclosures.

To learn more:

• nucleotide sequences
• WIPO Standard ST.26
• patent applications
• specifically defined nucleotides