Table 1. Example probabilities for resolved nucleotides and IUPAC ambiguity codes under an error model.

Code	Meaning	Probabilities (A, C, G, T)
A	A	1 − ε, ε/3, ε/3, ε/3
M	A or C	1 − 2ε/3, 1 − 2ε/3, 2ε/3, 2ε/3
V	A or C or G	1 − ε/3, 1 − ε/3, 1 − ε/3, ε
N	Any base	1, 1, 1, 1

IUPAC, International Union of Pure and Applied Chemistry.