What is considered a “nucleotide” in a Sequence Listing XML?

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 2412.03(d), a “nucleotide” in a Sequence Listing XML includes:

• Any nucleotide
• Nucleotide analogs
• Modified nucleotides

The MPEP, citing WIPO Standard ST.26, specifies that a nucleotide must contain:

1. A backbone moiety (e.g., 2′ deoxyribose 5′ monophosphate or an analogue)
2. Either a nucleobase (including modified or synthetic purines or pyrimidines) or an “AP site” (abasic site)

Nucleotide analogs that mimic the arrangement of nucleobases in natural nucleic acids and can base pair with complementary nucleic acids are also included in this definition.