What symbols should be used to represent nucleotides in a sequence?

According to MPEP 2412.05(b), the symbols for representing nucleotides in a sequence are as follows:

• Use only lower-case letters
• Refer to Table 1: List of Nucleotides Symbols in MPEP 2412.03(a)
• The symbol “t” represents thymine in DNA and uracil in RNA
• Use the most restrictive ambiguity symbol when appropriate
• The symbol “n” represents any nucleotide or an unknown nucleotide

The MPEP states, “All nucleotides, including nucleotide analogs, modified nucleotides, and “unknown” nucleotides, within a nucleotide sequence must be represented using the symbols set forth in paragraphs 13–16, 19, and 21 of WIPO Standard ST.26.” This ensures consistency and clarity in sequence representations.

To learn more:

• nucleotide symbols
• sequence representation
• WIPO Standard ST.26
• ambiguity symbols