How should regions of contiguous ‘X’ residues be described in an amino acid sequence?

The MPEP 2412.05(d) provides guidance on describing regions of contiguous ‘X’ residues in amino acid sequences:

• Use the syntax “x..y” as the location descriptor
• Apply this for regions with a known number of contiguous ‘X’ residues
• Use this approach when the same description applies to all ‘X’ residues in the region

The MPEP states, “WIPO Standard ST.26, paragraph 34, provides that a region containing a known number of contiguous “X” residues for which the same description applies may be jointly described using the syntax “x..y” as the location descriptor in the element INSDFeature_location” (see MPEP § 2413.01(g) subsection IV, for information regarding INSDFeature_location). This approach simplifies the representation of regions with multiple unknown amino acids in sequence listings.

To learn more:

• contiguous X residues
• sequence representation
• WIPO Standard ST.26
• location descriptor