Nucleotide Symbols
| Symbol | Meaning | Complement | Significance |
|---|---|---|---|
| A | A | T or U | Adenine |
| C | C | G | Cytosine |
| G | G | C | Guanine |
| T or U | T | A | Thymine or Uracil |
| M | A or C | K | aMino |
| R | A or G | Y | puRine |
| W | A or T | W | Weak (2 H-bonds) |
| S | C or G | S | Strong (3 H-bonds) |
| Y | C or T | R | pYrimidine |
| K | G or T | M | Keto |
| V | A or C or G | B | not T or not U |
| H | A or C or T | D | not G |
| D | A or G or T | H | not C |
| B | C or G or T | V | not A |
| N or X | A or C or G or T | X or N | aNy nucleotide |