The editor for sequence data recognizes predefined symbols for nucleotide and protein sequences according the IUPAC definitions.
| Symbol | Name |
| A | Adenine |
| C | Cytosine |
| G | Guanine |
| T | Thymine |
| U | Uracile |
| W | Weak (A or T) |
| S | Strong (G or C) |
| M | aMino (A or C) |
| K | Keto (G or T) |
| R | puRine (G or A) |
| Y | pYrimidine (C or T) |
| B | not A (B comes after A) |
| D | not C (D comes after C) |
| H | not G (H comes after G) |
| V | not T (V comes after T and U) |
| N | No idea (not a gap) |
| - | gap symbol |
| X | wrong entry |
The symbols with yellow background are ambiguity symbols. The difference between "N" and a gap symbol ("-") is that a gap symbol represents an unspecified number of unknown symbols but "N" stands for exatly one nucleic acid. Wrong symbols are marked with a brown background.