An ambiguity symbol is one of 11 symbols (the letters 'B', 'D', 'H', 'K', 'M', 'N', 'R', 'S', 'V', 'W', 'Y') that are used in IUPAC notation to represent uncertainty at a particular nucleotide position in a DNA string, in addition to the standard DNA alphabet {A, C, G, T}. Ambiguity symbols were created to encode single-nucleotide variations.
For example, the symbol 'D' could represent either 'A', 'G', or 'T'. See the table below for a complete description of ambiguity symbols.
