What is a nucleotide label?
Any nucleotide can have a number next to it with a line pointing from the number to the nucleotide (alternatively, just the line pointing to the nucleotide). This number isn’t necessarily the ordinal number of the nucleotide in its strand as sometimes it is useful to use a numbering system that is derived from a different strand. Typically every 10th nucleotide number in a secondary structure graph is labeled. Sometimes every 50th nucleotide is numbered while every 10th has a line next to it.
